Calvin Hsia's WebLog : LINQ

Use a dictionary to help create a mnemonic

Calvin_Hsia — Fri, 06 Jun 2008 22:36:00 GMT

I was using a program that was yet another TLA and I wanted to create a mnemonic to help me remember what it was. One of the letters was “k”, so I wanted to find a word that starts with “k”

Simple: load a dictionary, search for words starting with “k” and browse through them: “Killer” sounded fine!

The Dictionary dll (that you can download from the link below) actually contains 2 separate dictionaries in 679k bytes! The big one (Dictnum=1) has 171,201 words. The smaller (DictNum=2) has 53,869. These dictionaries are spelling dictionaries from the last century.

The samples below also demonstrate a simple LINQ query on the data:

I wanted to use common words, so I used the smaller one.

Fox code:

x=CREATEOBJECT("dictionary.dict")

x.Dictnum=2 && small dictionary

?x.FindMatches("k*")

cnt=x.words.count

CREATE CURSOR words (word c(20))

FOR i = 0 TO cnt-1

?x.Words.Item(i)

INSERT INTO words (word) VALUES (x.words.item(i))

ENDFOR

SELECT * FROM words WHERE AT("ill",word)>0

For VB code, Start VS, File->New->Project->VB->WindowsApplication->Console Application

We don’t have to reference the DLL (unless you want intellisense or use queries directly on the word collection) because late binding works.

(Since the DLL is 32 bit, if you’re using a 64 bit OS, make sure you make Project->Properties->Compile->Advanced Compiler Settings->Target CPU x86)

Module Module1

Sub Main()

Dim x = CreateObject("dictionary.dict")

'Dim x = New Dictionary.CDict ' use early binding: add a ref to Dictionary 1.0 Type Library

x.DictNum = 2 ' small dictionary

x.FindMatches("k*")

Dim col As New List(Of String) ' for late bindinq queries, we'll add to a list

For Each word In x.words

Debug.WriteLine(word)

col.Add(word)

For Each word In From a In col Where a.Contains("ill")

Debug.WriteLine(word)

End Sub

End Module

For C#, add a reference to “Dictionary 1.0 Type Library” in the COM tab.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{

class Program

{

static void Main(string[] args)

{

var x = new Dictionary.CDictClass();

x.DictNum = 2;

x.FindMatches("k*");

foreach (var word in x.Words)

{

System.Diagnostics.Debug.WriteLine(word);

}

var q = from string a in x.Words where a.Contains("ill") select a;

foreach (var w in q)

{

System.Diagnostics.Debug.WriteLine(w);

}

Download the dictionary from here: A Discounter Introduces Reductions: Multiple Anagrams

You can create many word related games.

More word games:

Write your own hangman game

The Nametag Game

Create your own typing tutor!

Carburetor is a car part, but prosecutable is not

What mnemonic can you create from your phone number? See Phone Number Challenge update

Persist user form size and location settings per session

Calvin_Hsia — Thu, 03 Apr 2008 02:57:00 GMT

My prior post (Create your own Test Host using XAML to run your unit tests) shows how to create a form and present it to the user. The user can resize and reposition the form, even on a 2^nd monitor.

When the user exits the form, we can persist or remember the form size and location, so the next time the user form starts up, it will be positioned/sized as before.

The happens to be a XAML form, but it could be a WinForm for this to work. (The My.Settings feature has been in Visual Studio for many years…)

Because FoxPro has its own database engine, Fox can persist data in a Fox table. The positions and sizes of design time windows, such as the Command Window, Project Window, Database Windows, are persisted in the FoxPro Resource file. The FoxResource class (unzip the xsource.zip file in tools\xsource and look in the EnvMgr folder) can help users persist user forms there too.

To add this feature to your VB project:

Go to Project->Properties->Settings, and add 2 settings:

Location, type=System.Drawing.Point, default = 0,0
Size, type=System.Drawing.Size, default=1024,768

In the Load or New method:

If System.Windows.Forms.Screen.AllScreens.Count = 1 AndAlso _

My.Settings.Location.X > System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Width Then

Me.Left = 0 ' if the saved .X is out of range (multimonitor, remote desktop)

Else

Me.Left = My.Settings.Location.X

End If

Me.Top = My.Settings.Location.Y

Me.Width = My.Settings.Size.Width

Me.Height = My.Settings.Size.Height

AddHandler Me.Closed, AddressOf OnWindowClosed

Sub OnWindowClosed(ByVal sender As Object, ByVal e As EventArgs)

My.Settings.Location = New System.Drawing.Point(CInt(Me.Left), CInt(Me.Top))

My.Settings.Size = New System.Drawing.Size(CInt(Me.Width), CInt(Me.Height))

My.Settings.Save()

End Sub

The data is stored in an XML file like:

"C:\Documents and Settings\Calvinh\Local Settings\Application Data\Microsoft\<appname>\1.0.0.0\user.config”

which looks like:

<?xml version="1.0" encoding="utf-8"?>

<<appname>.My.MySettings>

</setting>

</setting>

</<appname>.My.MySettings>

</userSettings>

</configuration>

If you’re feeling brave, you can persist multiple strings using System.Collections.Specialized.StringCollection.

I store things like which items are selected and how many asserts are fired per test. Each string will have 3 comma separated items: TestClass,TestName, and AssertCnt

For Each itm In m_TestMethods

Dim theitem = itm

Dim res = From a In My.Settings.AssertsPerTest _

Let strs = CStr(a).Split(","c) _

Where strs(0) = theitem.TestClass And strs(1) = theitem.TestName _

Let Assertcnt = CInt(strs(2))

If res.Count > 0 Then

itm.AssertCnt = res.First.Assertcnt

End If

And just before My.Settings.Save is called, we’ll create the string collection to save.

Dim ColAssertsPerTest = New Specialized.StringCollection

For Each itm In From d In TestMethods Where d.AssertCnt > 0

ColAssertsPerTest.Add(itm.TestClass + "," + itm.TestName + "," + itm.AssertCnt.ToString)

My.Settings.AssertsPerTest = ColAssertsPerTest

Notice the use of Linq in the For Each expressions.

I also use Linq to find the total # of asserts fired:

Dim nTotalAssertsExpected = Aggregate itm In m_SelectedTests Into Sum(itm.AssertCnt)

See also: another example of persisting settings: The VB version of the Blog Crawler

Use XLINQ to query the references in your project

Calvin_Hsia — Tue, 29 Jan 2008 20:11:00 GMT

Visual studio creates project files for you for the various languages, such as C++, C#, VB. These files are XML format, and can thus be queried.

Try this: open any non-temporary Visual Studio project (see Use temporary projects in Visual Studio), right click on it in solution explorer, choose unload, then right click again, then choose edit. This opens the Proj file (.vbproj,.csproj) in the XML editor

I wanted a way to get just the References in a list, so I started to write an XLINQ query of the XML.

I kept getting no results, until I saw that the XML has a namespace that I didn’t notice at first:

<?xml version="1.0" encoding="utf-8"?>

So I just needed to add an IMPORTS for the XML NameSpace

Imports <xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

Public Class Form1

Dim sample = _

<SpecificVersion>False</SpecificVersion>

<HintPath>..\..\..\..\binaries\x86chk\bin\i386\Microsoft.VisualStudio.CoreUtilityImplementation.dll</HintPath>

</Reference>

Function trimcomma(ByVal s As String)

'strip anything past comma <Reference Include="somedllname, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">

If s.IndexOf(",") > 0 Then

Return s.Substring(0, s.IndexOf(","))

End If

Return s

End Function

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

' the path of the current project

Dim xmlfile = My.Application.Info.DirectoryPath.Replace("\bin\Debug", "") + "\" + My.Application.Info.AssemblyName + ".vbproj"

Dim xmlSrc = XDocument.Load(xmlfile)

Me.Height = 800

Me.Width = 1000

Dim query = From a In xmlSrc...<Reference> _

Select r1 = trimcomma(a.@<Include>)

For Each ref In query

System.Diagnostics.Debug.WriteLine(ref)

Dim lbx As New ListBox

lbx.Width = Me.Width

lbx.Height = Me.Height

lbx.DataSource = query.ToArray

Me.Controls.Add(lbx)

lbx.Visible = True

End Sub

End Class

How to Create dynamic XAML to display arbitrary XML

Calvin_Hsia — Thu, 06 Dec 2007 23:37:00 GMT

Here's a sample of creating dynamic XAML to display arbitrary XML

You can use the XML DataProvider to supply XML data to XAML, a web service, or you can use a Query. Each way, you can generate XAML dynamically to display the XML. (echoes of XSLT)

I took the prior sample (Create your own media browser: Display your pictures, music, movies in a XAML tooltip) and changed the query to generate XML:

Dim Query = _

From file In IO.Directory.GetFiles(_rootFolder, _

"*.*", IO.SearchOption.AllDirectories) _

Select file, Ext = IO.Path.GetExtension(file).ToLower() _

Where Ext.Length > 0 AndAlso ".avi .jpg .mid .mpg .wma .wmv".Contains(Ext) _

Select <File>

</File>

The query result is an IEnumerable(Of System.Xml.Linq.XElement), which is passed to the Browse class, which dynamically finds the XML elements and binds the XAML

The Browse code detects if the query is an Anonymous Type or XML. Either way, it dynamically creates the columns for displaying the results of a query that creates XML.

Code using the XMLProvider to supply the XML results of a query are shown below too (Query3). Note that the XAML for the ListBox is hardcoded to the XML Elements, such as Filename and Size. It the query were to change, then the XAML will have to change too.

Use LINQ to Foxpro or any SQL data and display it in a WPF form using DataSetExtensions and DataRowExtensions

Calvin_Hsia — Sat, 01 Dec 2007 00:10:00 GMT

In the last post Create your own media browser: Display your pictures, music, movies in a XAML tooltip, we created a query of your local media and displayed it.

Today, we'll make a query to my Foxpro picture database of 28,000 pictures/movies. We'll make the query result structure to be similar to the prior post, so the same code will show the picture or movie in a tooltip. The query is for "wheel", which includes pictures of cartwheels, Ferris Wheels, wheelbarrows.

We can use the System.Data.DataRowExtensions to access the DataTable filled by the OledbDataAdapter without using DLINQ

Change the query statement from the last post to the snippet below

Dim Query

If True Then ' if you want the prior sample, just change this to false

Dim dt As New DataTable

_rootFolder = "e:\Pictures"

Dim da = New OleDbDataAdapter( _

"Select fullname as FileName,Notes from mypix where 'wheel'$lower(notes)", _

"Provider=VFPOLEDB.1;Data Source=" + _rootFolder + "\mypix.dbf")

da.Fill(dt)

Query = From picrow In dt.AsEnumerable _

Select FileName = picrow.Field(Of String)("FileName"), _

Description = picrow.Field(Of String)("Notes") _

Select FileName, _

Description, _

Type = IO.Path.GetExtension(FileName).Substring(1), _

Size = (New IO.FileInfo(_rootFolder + IO.Path.DirectorySeparatorChar + FileName)).Length

Else

Query = From file In IO.Directory.GetFiles(_rootFolder, _

"*.*", IO.SearchOption.AllDirectories) _

Select file, Ext = IO.Path.GetExtension(file).ToLower _

Where Ext.Length > 0 AndAlso ".avi .jpg .mid .mpg .wma .wmv".Contains(Ext) _

Select FileName = file.Substring(_rootFolder.Length + 1), _

Type = Ext.Substring(1), _

Size = (New IO.FileInfo(file)).Length

End If

</Snippet>

For the full working sample:

Start Visual Studio 2008

Choose File->New Project->Visual Basic->WPF Application

Double click the form designer to bring up the Window1.xaml.vb file. Replace the contents with the code below.

Change the oledb provider connection string to your data

Hit F5 to run the program

Imports System.Windows.Controls.Primitives ' for Popup

Imports System.Data

Imports System.Data.OleDb

Imports System.Data.DataTableExtensions

Partial Public Class Window1

Dim _rootFolder As String = System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800 : Me.Height = 800

Dim Query

If True Then ' if you want the prior sample, just change this to false

Dim dt As New DataTable

_rootFolder = "e:\Pictures"

Dim da = New OleDbDataAdapter( _

"Select fullname as FileName,Notes from mypix where 'wheel'$lower(notes)", _

"Provider=VFPOLEDB.1;Data Source=" + _rootFolder + "\mypix.dbf")

da.Fill(dt)

Query = From picrow In dt.AsEnumerable _

Select FileName = picrow.Field(Of String)("FileName"), _

Description = picrow.Field(Of String)("Notes") _

Select FileName, _

Description, _

Type = IO.Path.GetExtension(FileName).Substring(1), _

Size = (New IO.FileInfo(_rootFolder + IO.Path.DirectorySeparatorChar + FileName)).Length

Else

Query = From file In IO.Directory.GetFiles(_rootFolder, _

"*.*", IO.SearchOption.AllDirectories) _

Select file, Ext = IO.Path.GetExtension(file).ToLower _

Where Ext.Length > 0 AndAlso ".avi .jpg .mid .mpg .wma .wmv".Contains(Ext) _

Select FileName = file.Substring(_rootFolder.Length + 1), _

Type = Ext.Substring(1), _

Size = (New IO.FileInfo(file)).Length

End If

Me.Content = New BrowseWithMedia(Query, Me)

Me.Title = _rootFolder + " #Items = " + _

CType(Me.Content, BrowseWithMedia).Items.Count.ToString

End Sub

Private Sub Window1_Deactivated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Deactivated

Dim pop = CType(Me.Content, BrowseWithMedia)._lvPopUp ' no popup if user changes active window (Alt-Tab)

If Not pop Is Nothing AndAlso pop.IsOpen Then

pop.IsOpen = False

End If

End Sub

Private Class BrowseWithMedia : Inherits Browse

Dim _Parent As Window1 ' reference to container

Friend _lvPopUp As Popup ' popup window to show tip with movie

Dim WithEvents _lvTimer As New System.Windows.Threading.DispatcherTimer ' timer: after delay, show tip

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

MyBase.new(Query, Parent)

_Parent = Parent

End Sub

Sub HandleWheel(ByVal sp As StackPanel, ByVal e As System.Windows.Input.MouseWheelEventArgs) 'Handles Me.MouseWheel

Dim transform = CType(sp.RenderTransform, ScaleTransform)

Dim melem As MediaElement = sp.Children(1)

If e.Delta > 0 Then

melem.Height *= 1.1

melem.Width *= 1.1

'transform.ScaleX *= 1.1 ' to scale tip text too

'transform.ScaleY *= 1.1

Else

'transform.ScaleX /= 1.1

'transform.ScaleY /= 1.1

melem.Height /= 1.1

melem.Width /= 1.1

End If

End Sub

Dim _mdownPt As Point

Sub HandleClick(ByVal sp As StackPanel, ByVal e As MouseButtonEventArgs)

If sp.IsMouseCaptured Then

sp.ReleaseMouseCapture()

End If

If e.LeftButton = MouseButtonState.Pressed Then

_mdownPt = Mouse.GetPosition(sp) ' record mouse pos relative to sp

sp.CaptureMouse()

End If

End Sub

Sub HandleMouseMove(ByVal sp As StackPanel, ByVal e As MouseEventArgs)

If Mouse.LeftButton = MouseButtonState.Pressed Then

If sp.CaptureMouse Then

Dim curpt As Point = sp.PointToScreen(Mouse.GetPosition(sp))

_lvPopUp.HorizontalOffset = curpt.X - _mdownPt.X ' subtract mouse pos rel to sp

_lvPopUp.VerticalOffset = curpt.Y - _mdownPt.Y

_lvPopUp.Placement = PlacementMode.Absolute ' PlacementMode.Mouse

End If

End Sub

Sub HandlePopupTimerTick() Handles _lvTimer.Tick ' show the popup

_lvTimer.IsEnabled = False ' enabled in HandleRowSelected

Dim lbi As ListBoxItem = Me.ItemContainerGenerator.ContainerFromIndex(Me.SelectedIndex)

If Not lbi Is Nothing Then

Dim sp As New StackPanel

Dim cSrcFile = _Parent._rootFolder + IO.Path.DirectorySeparatorChar + lbi.Content.FileName.ToString

Dim XAMLPopup = _

<Popup

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Placement="Right"

IsOpen="False"

<StackPanel.RenderTransform>

</StackPanel.RenderTransform>

<%= cSrcFile + " " + CType(lbi.Content.size / 1024, Int32).ToString("n0") + "K" %>

</TextBlock>

<MediaElement

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Name="MyVid" Height="250">

<MediaElement.Triggers>

<EventTrigger.Actions>

Storyboard.TargetName="MyVid"

RepeatBehavior="Forever"/>

</Storyboard>

</BeginStoryboard>

</EventTrigger.Actions>

</EventTrigger>

</MediaElement.Triggers>

</MediaElement>

</StackPanel>

</Popup>

_lvPopUp = System.Windows.Markup.XamlReader.Load(XAMLPopup.CreateReader)

_lvPopUp.PlacementTarget = lbi

_lvPopUp.IsOpen = True

Dim stackpanel As StackPanel = _lvPopUp.Child ' only child is the stackpanel

AddHandler stackpanel.MouseWheel, AddressOf HandleWheel ' mouse wheel will zoom in/out

AddHandler stackpanel.MouseDown, AddressOf HandleClick ' mouse click/drag will move picture/movie

AddHandler stackpanel.MouseUp, AddressOf HandleClick

AddHandler stackpanel.MouseMove, AddressOf HandleMouseMove

End If

End Sub

Sub HandleRowSelected(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles Me.SelectionChanged

Dim lb = CType(sender, ListBox)

If Not lb Is Nothing AndAlso (lb.SelectedIndex >= 0) Then

Dim lbi As ListBoxItem = lb.ItemContainerGenerator.ContainerFromIndex(lb.SelectedIndex)

If Not _lvPopUp Is Nothing AndAlso _lvPopUp.IsOpen Then

_lvPopUp.IsOpen = False

End If

_lvTimer.Stop() ' stop prior timer, if any

_lvTimer.Interval = TimeSpan.FromMilliseconds(500)

_lvTimer.Start()

End If

End Sub

End Class

Class Browse

Inherits ListView

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

Dim gv As New GridView

Me.View = gv

Me.ItemsSource = Query

If Not Parent Is Nothing Then

If Parent.GetType.BaseType Is GetType(Window) Then

CType(Parent, Window).Title = "# items = " + Me.Items.Count.ToString

End If

Me.AddHandler(GridViewColumnHeader.ClickEvent, New RoutedEventHandler(AddressOf HandleHeaderClick))

For Each mem In From mbr In _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName) _

.GetGenericArguments()(0).GetMembers _

Where mbr.MemberType = Reflection.MemberTypes.Property

Dim coltype = CType(mem, Reflection.PropertyInfo).PropertyType.Name

Select Case coltype

Case "Int32", "String", "Int64"

Dim gvc As New GridViewColumn

gvc.Header = mem.Name

gv.Columns.Add(gvc)

If coltype <> "String" Then

gvc.Width = 80

Dim XAMLdt = _

<DataTemplate

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

<TextBlock Name="tb"

Text=<%= "{Binding Path=" + mem.Name + "}" %>

Foreground="Black"

FontWeight="Bold"

Background="SpringGreen">

</TextBlock>

</StackPanel>

</DataTemplate>

gvc.CellTemplate = System.Windows.Markup.XamlReader.Load(XAMLdt.CreateReader)

Else

gvc.DisplayMemberBinding = New Binding(mem.Name)

gvc.Width = 180

End If

End Select

Dim XAMLlbStyle = _

<Style

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

TargetType="ListBoxItem">

<Style.Triggers>

</Trigger>

</Trigger>

</Style.Triggers>

</Style>

Me.ItemContainerStyle = Windows.Markup.XamlReader.Load(XAMLlbStyle.CreateReader)

End Sub

Dim _Lastdir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

Dim _LastHeaderClicked As GridViewColumnHeader = Nothing

Sub HandleHeaderClick(ByVal sender As Object, ByVal e As RoutedEventArgs)

If e.OriginalSource.GetType Is GetType(GridViewColumnHeader) Then

Dim gvh = CType(e.OriginalSource, GridViewColumnHeader)

Dim dir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

If Not gvh Is Nothing AndAlso Not gvh.Column Is Nothing Then

Dim hdr = gvh.Column.Header

If gvh Is _LastHeaderClicked Then

If _Lastdir = ComponentModel.ListSortDirection.Ascending Then

dir = ComponentModel.ListSortDirection.Descending

End If

Sort(hdr, dir)

_LastHeaderClicked = gvh

_Lastdir = dir

End If

End Sub

Sub Sort(ByVal sortby As String, ByVal dir As System.ComponentModel.ListSortDirection)

Me.Items.SortDescriptions.Clear()

Dim sd = New System.ComponentModel.SortDescription(sortby, dir)

Me.Items.SortDescriptions.Add(sd)

Me.Items.Refresh()

End Sub

End Class

</Sample Code>

Create your own media browser: Display your pictures, music, movies in a XAML tooltip

Calvin_Hsia — Thu, 29 Nov 2007 21:46:00 GMT

In my prior post, I showed how to use XAML and XAMLReader to create inline XAML to display the results of a query.

Today, let's take it a step further: let's create a query of all the media (pictures, movies, music) in your "My Documents" folder and display the names and sizes in a ListView. As you navigate the list, a tooltip appears showing the media.

You can click on the tip and move it around the screen, or you can mousewheel to zoom in and out.

The code illustrates how to use inline XAML to create hierarchies of UI Elements and get references to those objects to add event handlers. It also shows how to create a databinding DataTemplate and Style with inline XAML.

To get your Foxpro database pictures into this code, see Various ways to display multiple photographs

Start Visual Studio 2008

Choose File->New Project->Visual Basic->WPF Application

You can use the WPF Forms designer, or you can write your code in a program.

Double click the form designer to bring up the Window1.xaml.vb file. Replace the contents with the code below.

Hit F5 to run the program

The query scans your "My Documents" folder for various file types. You can change those types in the query.

Imports System.Windows.Controls.Primitives ' for Popup

Partial Public Class Window1

Dim _rootFolder As String = System.Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800 : Me.Height = 800

Dim Query = From file In IO.Directory.GetFiles(_rootFolder, _

"*.*", IO.SearchOption.AllDirectories) _

Select file, Ext = IO.Path.GetExtension(file).ToLower _

Where Ext.Length > 0 AndAlso ".avi .jpg .mid .mpg .wma .wmv".Contains(Ext) _

Select FileName = file.Substring(_rootFolder.Length + 1), _

Type = Ext.Substring(1), _

Size = (New IO.FileInfo(file)).Length

Me.Content = New BrowseWithMedia(Query, Me)

Me.Title = _rootFolder + " #Items = " + _

CType(Me.Content, BrowseWithMedia).Items.Count.ToString

End Sub

Private Sub Window1_Deactivated(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Deactivated

Dim pop = CType(Me.Content, BrowseWithMedia)._lvPopUp ' no popup if user changes active window (Alt-Tab)

If Not pop Is Nothing AndAlso pop.IsOpen Then

pop.IsOpen = False

End If

End Sub

Private Class BrowseWithMedia : Inherits Browse

Dim _Parent As Window1 ' reference to container

Friend _lvPopUp As Popup ' popup window to show tip with movie

Dim WithEvents _lvTimer As New System.Windows.Threading.DispatcherTimer ' timer: after delay, show tip

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

MyBase.new(Query, Parent)

_Parent = Parent

End Sub

Sub HandleWheel(ByVal sp As StackPanel, ByVal e As System.Windows.Input.MouseWheelEventArgs) 'Handles Me.MouseWheel

Dim transform = CType(sp.RenderTransform, ScaleTransform)

Dim melem As MediaElement = sp.Children(1)

If e.Delta > 0 Then

melem.Height *= 1.1

melem.Width *= 1.1

'transform.ScaleX *= 1.1 ' to scale tip text too

'transform.ScaleY *= 1.1

Else

'transform.ScaleX /= 1.1

'transform.ScaleY /= 1.1

melem.Height /= 1.1

melem.Width /= 1.1

End If

End Sub

Dim _mdownPt As Point

Sub HandleClick(ByVal sp As StackPanel, ByVal e As MouseButtonEventArgs)

If sp.IsMouseCaptured Then

sp.ReleaseMouseCapture()

End If

If e.LeftButton = MouseButtonState.Pressed Then

_mdownPt = Mouse.GetPosition(sp) ' record mouse pos relative to sp

sp.CaptureMouse()

End If

End Sub

Sub HandleMouseMove(ByVal sp As StackPanel, ByVal e As MouseEventArgs)

If Mouse.LeftButton = MouseButtonState.Pressed Then

If sp.CaptureMouse Then

Dim curpt As Point = sp.PointToScreen(Mouse.GetPosition(sp))

_lvPopUp.HorizontalOffset = curpt.X - _mdownPt.X ' subtract mouse pos rel to sp

_lvPopUp.VerticalOffset = curpt.Y - _mdownPt.Y

_lvPopUp.Placement = PlacementMode.Absolute ' PlacementMode.Mouse

End If

End Sub

Sub HandlePopupTimerTick() Handles _lvTimer.Tick ' show the popup

_lvTimer.IsEnabled = False ' enabled in HandleRowSelected

Dim lbi As ListBoxItem = Me.ItemContainerGenerator.ContainerFromIndex(Me.SelectedIndex)

If Not lbi Is Nothing Then

Dim sp As New StackPanel

Dim cSrcFile = _Parent._rootFolder + IO.Path.DirectorySeparatorChar + lbi.Content.FileName.ToString

Dim XAMLPopup = _

<Popup

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Placement="Right"

IsOpen="False"

<StackPanel.RenderTransform>

</StackPanel.RenderTransform>

<%= cSrcFile + " " + CType(lbi.Content.size / 1024, Int32).ToString("n0") + "K" %>

</TextBlock>

<MediaElement

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Name="MyVid" Height="250">

<MediaElement.Triggers>

<EventTrigger.Actions>

Storyboard.TargetName="MyVid"

RepeatBehavior="Forever"/>

</Storyboard>

</BeginStoryboard>

</EventTrigger.Actions>

</EventTrigger>

</MediaElement.Triggers>

</MediaElement>

</StackPanel>

</Popup>

_lvPopUp = System.Windows.Markup.XamlReader.Load(XAMLPopup.CreateReader)

_lvPopUp.PlacementTarget = lbi

_lvPopUp.IsOpen = True

Dim stackpanel As StackPanel = _lvPopUp.Child ' only child is the stackpanel

AddHandler stackpanel.MouseWheel, AddressOf HandleWheel ' mouse wheel will zoom in/out

AddHandler stackpanel.MouseDown, AddressOf HandleClick ' mouse click/drag will move picture/movie

AddHandler stackpanel.MouseUp, AddressOf HandleClick

AddHandler stackpanel.MouseMove, AddressOf HandleMouseMove

End If

End Sub

Sub HandleRowSelected(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles Me.SelectionChanged

Dim lb = CType(sender, ListBox)

If Not lb Is Nothing AndAlso (lb.SelectedIndex >= 0) Then

Dim lbi As ListBoxItem = lb.ItemContainerGenerator.ContainerFromIndex(lb.SelectedIndex)

If Not _lvPopUp Is Nothing AndAlso _lvPopUp.IsOpen Then

_lvPopUp.IsOpen = False

End If

_lvTimer.Stop() ' stop prior timer, if any

_lvTimer.Interval = TimeSpan.FromMilliseconds(500)

_lvTimer.Start()

End If

End Sub

End Class

Class Browse

Inherits ListView

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

Dim gv As New GridView

Me.View = gv

Me.ItemsSource = Query

If Not Parent Is Nothing Then

If Parent.GetType.BaseType Is GetType(Window) Then

CType(Parent, Window).Title = "# items = " + Me.Items.Count.ToString

End If

Me.AddHandler(GridViewColumnHeader.ClickEvent, New RoutedEventHandler(AddressOf HandleHeaderClick))

For Each mem In From mbr In _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName) _

.GetGenericArguments()(0).GetMembers _

Where mbr.MemberType = Reflection.MemberTypes.Property

Dim coltype = CType(mem, Reflection.PropertyInfo).PropertyType.Name

Select Case coltype

Case "Int32", "String", "Int64"

Dim gvc As New GridViewColumn

gvc.Header = mem.Name

gv.Columns.Add(gvc)

If coltype <> "String" Then

gvc.Width = 80

Dim XAMLdt = _

<DataTemplate

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

<TextBlock Name="tb"

Text=<%= "{Binding Path=" + mem.Name + "}" %>

Foreground="Black"

FontWeight="Bold"

Background="SpringGreen">

</TextBlock>

</StackPanel>

</DataTemplate>

gvc.CellTemplate = System.Windows.Markup.XamlReader.Load(XAMLdt.CreateReader)

Else

gvc.DisplayMemberBinding = New Binding(mem.Name)

gvc.Width = 180

End If

End Select

Dim XAMLlbStyle = _

<Style

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

TargetType="ListBoxItem">

<Style.Triggers>

</Trigger>

</Trigger>

</Style.Triggers>

</Style>

Me.ItemContainerStyle = Windows.Markup.XamlReader.Load(XAMLlbStyle.CreateReader)

End Sub

Dim _Lastdir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

Dim _LastHeaderClicked As GridViewColumnHeader = Nothing

Sub HandleHeaderClick(ByVal sender As Object, ByVal e As RoutedEventArgs)

If e.OriginalSource.GetType Is GetType(GridViewColumnHeader) Then

Dim gvh = CType(e.OriginalSource, GridViewColumnHeader)

Dim dir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

If Not gvh Is Nothing AndAlso Not gvh.Column Is Nothing Then

Dim hdr = gvh.Column.Header

If gvh Is _LastHeaderClicked Then

If _Lastdir = ComponentModel.ListSortDirection.Ascending Then

dir = ComponentModel.ListSortDirection.Descending

End If

Sort(hdr, dir)

_LastHeaderClicked = gvh

_Lastdir = dir

End If

End Sub

Sub Sort(ByVal sortby As String, ByVal dir As System.ComponentModel.ListSortDirection)

Me.Items.SortDescriptions.Clear()

Dim sd = New System.ComponentModel.SortDescription(sortby, dir)

Me.Items.SortDescriptions.Add(sd)

Me.Items.Refresh()

End Sub

End Class

</Sample Code>

WPF Animation: Use dynamic XAML to animate movies using XAMLReader or animate in code using BeginStoryBoard

Calvin_Hsia — Wed, 28 Nov 2007 22:08:00 GMT

Using WPF, it’s great to use declarative XAML, but it’s also great to use dynamic code. With VB’s new XML Features, you can do either.

Below is a sample showing how to use XAMLReader to take XML generated in code and use it to create XAML to present as UI.

The XAMLPanel demonstrates some of the ease of defining UI via XAML, as well as hooking up events. You might want to use the XAML designer in Visual Studio 2008 to get the intellisense for the XAML.

The sample also demonstrates 2 types of WPF animation: how you can make movies repeat forever or animate a Dependency Property like a button’s Width. (Animating the movie (sounds redundant<g>) means to make it repeat after it finishes playing. )

The movie is animated with XAML, and the Button Width property is animated using DoubleAnimation

Use the code in my prior post (Use the DispatcherTimer, Popup and even a movie to enhance your data presentation) as a base, replace the 5 lines and the HandleClick from that sample that create “MyVid” with the snippet below:

If you try to add event handlers or use the x:Code for the dynamic XAML, an error occurs: “Must compile XAML file that specifies events. Line '0' Position '0'.” This makes sense.

<x:Code><![CDATA[

Sub HandleClick(Sender as object, e as RoutedEventArgs)

MsgBox("You Clicked me!")

End Sub

]]></x:Code>

Dim MyVid As MediaElement ' For more fun, let's add a movie to the popup tip

Dim cSrcFile = "d:\t.avi" '"c:\windows\media\chimes.wav"

If False Then ' set this to true for the original code

MyVid = New MediaElement

MyVid.MaxHeight = 100

MyVid.MaxWidth = 100

MyVid.Source = New Uri(cSrcFile) ' change to point to your movie file

Else

' define a child StackPanel in XAML

Dim XAMLPanel = _

<StackPanel

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Orientation="Vertical"

Background="Bisque"

<Button>Another button</Button>

<CheckBox>Check me</CheckBox>

<Button

BorderBrush="Green"

BorderThickness="2"

Background="LightBlue"

>ListBoxItemButton Click Me!</Button></ListBoxItem>

<TabItem Header="Col1"><Button>are we crazy?</Button></TabItem>

</TabControl>

</ListBoxItem>

</ListBox>

</StackPanel>

Dim sp2 As StackPanel = Windows.Markup.XamlReader.Load(XAMLPanel.CreateReader)

Dim btn2 As Button = sp2.Children(0)

btn2.AddHandler(Button.ClickEvent, New RoutedEventHandler(AddressOf HandleClick))

Dim lb As ListBox = sp2.Children(2)

Dim btn3 As Button = CType(lb.Items(0), ListBoxItem).Content

btn3.AddHandler(Button.ClickEvent, New RoutedEventHandler(AddressOf HandleClick))

sp.Children.Add(sp2)

'now add a movie that repeats. Must use Windows.Media.Animation.StoryBoard

'Use the inline XML feature of VB to create XAML

Dim XAMLMediaElem = _

<MediaElement

xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

Name="MyVid" Height="50.5">

<MediaElement.Triggers>

<EventTrigger.Actions>

Storyboard.TargetName="MyVid"

RepeatBehavior="Forever"/>

</Storyboard>

</BeginStoryboard>

</EventTrigger.Actions>

</EventTrigger>

</MediaElement.Triggers>

</MediaElement>

MyVid = Windows.Markup.XamlReader.Load(XAMLMediaElem.CreateReader)

' Equivalent of XAML in code:

'Dim tr As New EventTrigger

'MyVid.Triggers.Add(tr)

'tr.RoutedEvent = MediaElement.LoadedEvent

'Dim BeginSB As New Windows.Media.Animation.BeginStoryboard

'tr.Actions.Add(BeginSB)

'Dim Sboard As New Windows.Media.Animation.Storyboard

'BeginSB.Storyboard = Sboard

'Dim medTimeLine As New Windows.Media.MediaTimeline(New Uri(cSrcFile))

'medTimeLine.RepeatBehavior = Windows.Media.Animation.RepeatBehavior.Forever

'Sboard.Children.Add(medTimeLine)

btnTest.Name = "btnTest"

Dim tr = New EventTrigger

tr.RoutedEvent = Button.LoadedEvent

btnTest.Triggers.Add(tr)

Dim BeginSB = New Windows.Media.Animation.BeginStoryboard

tr.Actions.Add(BeginSB)

Dim Sboard = New Windows.Media.Animation.Storyboard

BeginSB.Storyboard = Sboard

Dim dbleAnim = New Windows.Media.Animation.DoubleAnimation

dbleAnim.From = 50

dbleAnim.To = 300

dbleAnim.Duration = New Duration(TimeSpan.FromMilliseconds(200))

dbleAnim.RepeatBehavior = Windows.Media.Animation.RepeatBehavior.Forever

dbleAnim.AutoReverse = True

''Windows.Media.Animation.Storyboard.SetTargetName(dbleAnim, btnTest.Name)

Windows.Media.Animation.Storyboard.SetTargetProperty(dbleAnim, New PropertyPath(Button.WidthProperty))

Sboard.Children.Add(dbleAnim)

End If

sp.Children.Add(MyVid)

End Sub

Sub HandleClick(ByVal sender As Object, ByVal e As RoutedEventArgs)

Dim b As Button = CType(e.OriginalSource, Button)

b.Content = "Thanks for clicking " + b.Content + DateTime.Now.ToString

'MsgBox("You Clicked me!")

End Sub

</Code Sample>

Use the DispatcherTimer, Popup and even a movie to enhance your data presentation

Calvin_Hsia — Thu, 22 Nov 2007 00:50:00 GMT

We can subclass the prior Windows Presentation Foundation (WPF) class called Browse that displays the results of a query. This subclass will add a WPF Popup to it.

The popup can easily be added to either a ListView or the ListBox sample I posted earlier (Use LINQ with WPF : Styles and DataTemplates in code)

The code sample below is exactly the same code as the prior Browse post except that it uses a subclass of the Browse class called BrowseWithPopup.

This class has a DispatcherTimer Class (System.Windows.Threading) that delays the opening of the descriptive popup. The timer starts when an item is selected. If it's been selected for, say 200 ms, then the popup displays. Thus, if the user is actively scrolling, no popup shows.

The System.Timers.Timer class runs in a different thread from the UI thread. WPF runs UI and rendering in different threads. See WPF Threading Model.

To add a movie to any UI element is quite simple. To make it repeat after playing once, you need to use the StoryBoard class to animate it. Try making it repeat forever!

Imports System.Windows.Controls.Primitives ' for Popup

Partial Public Class Window1

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800

Me.Height = 800

Dim Query = From proc In System.Diagnostics.Process.GetProcesses _

Select proc.Id, proc.ProcessName, ThreadCount = proc.Threads.Count, proc.MainWindowTitle

'Me.Content = New Browse(Query, Me) ' the Browse will fill the entire window

Me.Content = New BrowseWithPopup(Query, Me)

End Sub

End Class

Class Browse

Inherits ListView

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

Dim gv As New GridView

Me.View = gv

Me.ItemsSource = Query

If Not Parent Is Nothing Then

If Parent.GetType.BaseType Is GetType(Window) Then

CType(Parent, Window).Title = "# items = " + Me.Items.Count.ToString

End If

Me.AddHandler(GridViewColumnHeader.ClickEvent, New RoutedEventHandler(AddressOf HandleHeaderClick))

For Each mem In From mbr In _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName) _

.GetGenericArguments()(0).GetMembers _

Where mbr.MemberType = Reflection.MemberTypes.Property

Dim coltype = CType(mem, Reflection.PropertyInfo).PropertyType.Name

Select Case coltype

Case "Int32", "String"

Dim gvc As New GridViewColumn

gvc.Header = mem.Name

gv.Columns.Add(gvc)

If coltype = "Int32" Then

gvc.Width = 80

Dim dt As New DataTemplate

Dim factSP = New FrameworkElementFactory(GetType(StackPanel))

dt.VisualTree = factSP

factSP.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal)

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold)

' factTb.SetValue(TextBlock.BackgroundProperty, Brushes.SpringGreen)

factSP.AppendChild(factTb)

'factTb = New FrameworkElementFactory(GetType(Button))

'factTb.SetValue(Button.ContentProperty, "hit me")

'factSP.AppendChild(factTb)

gvc.CellTemplate = dt

Else

gvc.DisplayMemberBinding = New Binding(mem.Name)

gvc.Width = 180

End If

End Select

Dim MyListboxStyle As New Style(GetType(ListBoxItem))

Dim tr = New Trigger

tr.Property = ListBoxItem.IsSelectedProperty ' when Selected

tr.Value = True ' is true

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Bisque))

MyListboxStyle.Triggers.Add(tr)

tr = New Trigger

tr.Property = ListBoxItem.IsMouseOverProperty ' when mouseover

tr.Value = True ' is true

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Red))

tr.Setters.Add(New Setter(ListBoxItem.BackgroundProperty, Brushes.Aquamarine)) ' this trigger sets both fore and back properties

MyListboxStyle.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.RoyalBlue)) ' set style for all items

MyListboxStyle.Triggers.Add(tr)

Me.ItemContainerStyle = MyListboxStyle

End Sub

Dim _Lastdir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

Dim _LastHeaderClicked As GridViewColumnHeader = Nothing

Sub HandleHeaderClick(ByVal sender As Object, ByVal e As RoutedEventArgs)

If e.OriginalSource.GetType Is GetType(GridViewColumnHeader) Then

Dim gvh = CType(e.OriginalSource, GridViewColumnHeader)

Dim dir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

If Not gvh Is Nothing AndAlso Not gvh.Column Is Nothing Then

Dim hdr = gvh.Column.Header

If gvh Is _LastHeaderClicked Then

If _Lastdir = ComponentModel.ListSortDirection.Ascending Then

dir = ComponentModel.ListSortDirection.Descending

End If

Sort(hdr, dir)

_LastHeaderClicked = gvh

_Lastdir = dir

End If

End Sub

Sub Sort(ByVal sortby As String, ByVal dir As System.ComponentModel.ListSortDirection)

Me.Items.SortDescriptions.Clear()

Dim sd = New System.ComponentModel.SortDescription(sortby, dir)

Me.Items.SortDescriptions.Add(sd)

Me.Items.Refresh()

End Sub

End Class

Class BrowseWithPopup

Inherits Browse

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

MyBase.new(Query)

Dim sp As New StackPanel

_lvPopUp.Child = sp

_tbListViewItemDescription.Foreground = Brushes.Black

_tbListViewItemDescription.Background = Brushes.LightYellow

sp.Children.Add(_tbListViewItemDescription)

'Return ' the rest of this method is fluff

Dim btnTest As New Button ' just for fun, let's add a button to the popup tip.

btnTest.Content = "foo"

btnTest.AddHandler(Button.ClickEvent, New RoutedEventHandler(AddressOf HandleClick))

sp.Children.Add(btnTest)

Dim MyVid As New MediaElement ' For more fun, let's add a movie to the popup tip

MyVid.MaxHeight = 100

MyVid.MaxWidth = 100

MyVid.Source = New Uri("d:\tshort.avi") ' change to point to your movie file

sp.Children.Add(MyVid)

End Sub

Sub HandleClick()

MsgBox("You Clicked me!")

End Sub

Dim _lvPopUp As New Popup

Dim WithEvents _lvTimer As New System.Windows.Threading.DispatcherTimer

Dim _tbListViewItemDescription As New TextBlock

Sub HandlePopupTimerTick() Handles _lvTimer.Tick

Dim lbi As ListBoxItem = Me.ItemContainerGenerator.ContainerFromIndex(Me.SelectedIndex)

If Not lbi Is Nothing Then

_lvPopUp.PlacementTarget = lbi

_tbListViewItemDescription.Text = "This is the data: " + vbCrLf + lbi.Content.ToString

_lvPopUp.IsOpen = 1

End If

End Sub

Sub HandleRowSelected(ByVal sender As Object, ByVal e As RoutedEventArgs) Handles Me.SelectionChanged

Dim lb = CType(sender, ListBox)

If Not lb Is Nothing AndAlso (lb.SelectedIndex >= 0) Then

Dim lbi As ListBoxItem = lb.ItemContainerGenerator.ContainerFromIndex(lb.SelectedIndex)

Dim lbi2 = lb.SelectedItem

If _lvPopUp.IsOpen Then

_lvPopUp.IsOpen = False

End If

_lvTimer.Stop() ' stop prior timer, if any

_lvTimer.Interval = TimeSpan.FromMilliseconds(500)

_lvTimer.Start()

_lvPopUp.AllowsTransparency = True

_lvPopUp.PopupAnimation = PopupAnimation.Fade

_lvPopUp.Placement = PlacementMode.Right

End If

End Sub

End Class

</Code Sample>

Use DataTemplates and WPF in code to create a general purpose LINQ Query results display

Calvin_Hsia — Fri, 16 Nov 2007 00:23:00 GMT

In my last post, Use LINQ with WPF : Styles and DataTemplates in code, I showed how to use DataTemplates in code to show the results of a query in a ListBox.

Let's make a reusable class called Browse which creates WPF content as a ListView from a LINQ query and generates columns and headers. It also uses DataTemplates to databind

The headers will sort the columns when clicked. Also, you can resize and change the order of columns by clicking/dragging.

(For a Windows Forms version of Browse (not WPF) , see Cool Linq Query)

Start Visual Studio 2008 (or 2005 with Visual Studio 2005 extensions for .NET Framework 3.0. Linq is only in 2008)

Choose File->New Project->Visual Basic->WPF Application

You can use the WPF Forms designer, or you can write your code in a program.

Double click the form designer to bring up the Window1.xaml.vb file. Replace the contents with the code below.

Imports System.Windows.Controls.Primitives ' for Popup

Partial Public Class Window1

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800

Me.Height = 800

Dim Query = From proc In System.Diagnostics.Process.GetProcesses _

Select proc.Id, proc.ProcessName, ThreadCount = proc.Threads.Count, proc.MainWindowTitle

Me.Content = New Browse(Query, Me) ' the Browse will fill the entire window

'Me.Content = New BrowseWithPopup(Query, Me)

End Sub

End Class

Class Browse

Inherits ListView

Sub New(ByVal Query As Object, Optional ByVal Parent As Object = Nothing)

Dim gv As New GridView

Me.View = gv

Me.ItemsSource = Query

If Not Parent Is Nothing Then

If Parent.GetType.BaseType Is GetType(Window) Then

CType(Parent, Window).Title = "# items = " + Me.Items.Count.ToString

End If

Me.AddHandler(GridViewColumnHeader.ClickEvent, New RoutedEventHandler(AddressOf HandleHeaderClick))

For Each mem In From mbr In _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName) _

.GetGenericArguments()(0).GetMembers _

Where mbr.MemberType = Reflection.MemberTypes.Property

Dim coltype = CType(mem, Reflection.PropertyInfo).PropertyType.Name

Select Case coltype

Case "Int32", "String"

Dim gvc As New GridViewColumn

gvc.Header = mem.Name

gv.Columns.Add(gvc)

If coltype = "Int32" Then

gvc.Width = 80

Dim dt As New DataTemplate

Dim factSP = New FrameworkElementFactory(GetType(StackPanel))

dt.VisualTree = factSP

factSP.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal)

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold)

' factTb.SetValue(TextBlock.BackgroundProperty, Brushes.SpringGreen)

factSP.AppendChild(factTb)

'factTb = New FrameworkElementFactory(GetType(Button))

'factTb.SetValue(Button.ContentProperty, "hit me")

'factSP.AppendChild(factTb)

gvc.CellTemplate = dt

Else

gvc.DisplayMemberBinding = New Binding(mem.Name)

gvc.Width = 180

End If

End Select

Dim MyListboxStyle As New Style(GetType(ListBoxItem))

Dim tr = New Trigger

tr.Property = ListBoxItem.IsSelectedProperty ' when Selected

tr.Value = True ' is true

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Bisque))

MyListboxStyle.Triggers.Add(tr)

tr = New Trigger

tr.Property = ListBoxItem.IsMouseOverProperty ' when mouseover

tr.Value = True ' is true

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Red))

tr.Setters.Add(New Setter(ListBoxItem.BackgroundProperty, Brushes.Aquamarine)) ' this trigger sets both fore and back properties

MyListboxStyle.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.RoyalBlue)) ' set style for all items

MyListboxStyle.Triggers.Add(tr)

Me.ItemContainerStyle = MyListboxStyle

End Sub

Dim _Lastdir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

Dim _LastHeaderClicked As GridViewColumnHeader = Nothing

Sub HandleHeaderClick(ByVal sender As Object, ByVal e As RoutedEventArgs)

If e.OriginalSource.GetType Is GetType(GridViewColumnHeader) Then

Dim gvh = CType(e.OriginalSource, GridViewColumnHeader)

Dim dir As System.ComponentModel.ListSortDirection = ComponentModel.ListSortDirection.Ascending

If Not gvh Is Nothing AndAlso Not gvh.Column Is Nothing Then

Dim hdr = gvh.Column.Header

If gvh Is _LastHeaderClicked Then

If _Lastdir = ComponentModel.ListSortDirection.Ascending Then

dir = ComponentModel.ListSortDirection.Descending

End If

Sort(hdr, dir)

_LastHeaderClicked = gvh

_Lastdir = dir

End If

End Sub

Sub Sort(ByVal sortby As String, ByVal dir As System.ComponentModel.ListSortDirection)

Me.Items.SortDescriptions.Clear()

Dim sd = New System.ComponentModel.SortDescription(sortby, dir)

Me.Items.SortDescriptions.Add(sd)

Me.Items.Refresh()

End Sub

End Class

</Code Sample>

Use LINQ with WPF : Styles and DataTemplates in code

Calvin_Hsia — Mon, 12 Nov 2007 21:28:00 GMT

Using Windows Presentation Foundation (WPF) and LINQ is easy in code. We'll create a query and display it in a WPF ListBox

Using XAML is harder: the ObjectDataProvider class works with non-anonymous types.

Start Visual Studio 2008 (or 2005 with Visual Studio 2005 extensions for .NET Framework 3.0. Linq is only in 2008)

Choose File->New Project->Visual Basic->WPF Application

You can use the WPF Forms designer, or you can write your code in a program.

Double click the form designer to bring up the Window1.xaml.vb file. Replace the contents with the code below.

Class Window1

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800

Me.Height = 800

Dim Query = From proc In System.Diagnostics.Process.GetProcesses _

Select proc.Id, proc.ProcessName, ThreadCount = proc.Threads.Count, proc.MainWindowTitle

Dim MyListBox As New ListBox

MyListBox.ItemsSource = Query

' lb.ItemsSource = New String() {"one", "two"} ' or a simple array

Me.Content = MyListBox

End Sub

End Class

Hit F5, and now you have a ListBox on a form which displays multiple rows like so:

{ Id = 2312, ProcessName = notepad, ThreadCount =1, MainWindowTitle = t.txt – Notepad, }

Let's make the display a little more friendly by using a DataTemplate.

Add this code before the End Sub:

Dim dt As New DataTemplate

Dim factSP = New FrameworkElementFactory(GetType(StackPanel))

dt.VisualTree = factSP

factSP.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal)

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding("Id"))

factTb.SetValue(TextBlock.WidthProperty, 40.0)

factTb.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold)

factSP.AppendChild(factTb)

factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding("ProcessName"))

factTb.SetValue(TextBlock.FontStyleProperty, FontStyles.Italic)

factTb.SetValue(TextBlock.WidthProperty, 80.0)

factSP.AppendChild(factTb)

factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding("ThreadCount"))

factTb.SetValue(TextBlock.WidthProperty, 30.0)

factSP.AppendChild(factTb)

factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding("MainWindowTitle"))

factSP.AppendChild(factTb)

MyListBox.ItemTemplate = dt

This code uses a Data Template to map data names with UI elements.

Because there are multiple rows, the template declaratively specifies how the data is presented.

In this case, the multiple rows of the query mapped to multiple ListBoxItems in the ListBox. Each ListBoxItem displays as a factory generated Horizontal StackPanel. The StackPanel contains a factory generated TextBlock for each field. WPF allows all sorts of controls inside other controls, so we could have a movie or even another listbox inside the listbox item.

Some of the TextBlocks have their width or FontStyle set. However, this code is hardcoded for the field names and data types of the query. Let's make it more generic. We can use refection to get the data types and field names of the anonymous type created by the query:

Dim QueryAnonType = _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName).GetGenericArguments()(0)

For Each mem In QueryAnonType.GetMembers

If mem.MemberType = Reflection.MemberTypes.Property Then

Select Case CType(mem, Reflection.PropertyInfo).PropertyType.Name

Case "Int32"

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.WidthProperty, 40.0)

factTb.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold)

factSP.AppendChild(factTb)

Case "String"

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.WidthProperty, 130.0)

factTb.SetValue(TextBlock.FontStyleProperty, FontStyles.Italic)

factTb.SetValue(TextBlock.ForegroundProperty, Brushes.CornflowerBlue)

factSP.AppendChild(factTb)

End Select

End If

Putting it all together, adding some style triggers for fun, the entire code sample is below.

Next time, we'll add headers that sort the columns when clicked and some

Class Window1

Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded

Me.Width = 800

Me.Height = 800

Dim Query = From proc In System.Diagnostics.Process.GetProcesses _

Select proc.Id, proc.ProcessName, ThreadCount = proc.Threads.Count, proc.MainWindowTitle

Dim MyListBox As New ListBox

MyListBox.ItemsSource = Query

' lb.ItemsSource = New String() {"one", "two"} ' or a simple array

Me.Content = MyListBox

Dim dt As New DataTemplate

Dim factSP = New FrameworkElementFactory(GetType(StackPanel))

dt.VisualTree = factSP

factSP.SetValue(StackPanel.OrientationProperty, Orientation.Horizontal)

Dim QueryAnonType = _

Query.GetType().GetInterface(GetType(IEnumerable(Of )).FullName).GetGenericArguments()(0)

For Each mem In QueryAnonType.GetMembers

If mem.MemberType = Reflection.MemberTypes.Property Then

Select Case CType(mem, Reflection.PropertyInfo).PropertyType.Name

Case "Int32"

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.WidthProperty, 40.0)

factTb.SetValue(TextBlock.FontWeightProperty, FontWeights.Bold)

factSP.AppendChild(factTb)

Case "String"

Dim factTb = New FrameworkElementFactory(GetType(TextBlock))

factTb.SetBinding(TextBlock.TextProperty, New Binding(mem.Name))

factTb.SetValue(TextBlock.WidthProperty, 130.0)

factTb.SetValue(TextBlock.FontStyleProperty, FontStyles.Italic)

factTb.SetValue(TextBlock.ForegroundProperty, Brushes.CornflowerBlue)

factSP.AppendChild(factTb)

End Select

End If

MyListBox.ItemTemplate = dt

Dim MyListboxStyle As New Style(GetType(ListBoxItem))

Dim tr = New Trigger

tr.Property = ListBoxItem.IsSelectedProperty

tr.Value = True

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Bisque))

MyListboxStyle.Triggers.Add(tr)

tr = New Trigger

tr.Property = ListBoxItem.IsMouseOverProperty

tr.Value = True

tr.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Red))

tr = New Trigger

tr.Property = ListBoxItem.IsMouseOverProperty

tr.Value = True

tr.Setters.Add(New Setter(ListBoxItem.BackgroundProperty, Brushes.Aquamarine))

MyListboxStyle.Setters.Add(New Setter(ListBoxItem.ForegroundProperty, Brushes.Black))

MyListboxStyle.Triggers.Add(tr)

MyListBox.ItemContainerStyle = MyListboxStyle

End Sub

End Class

</Code Sample>