Jimmy Rasmussens Blog

Code Contracts

jimmytr — Sat, 25 Apr 2009 23:00:00 GMT

pre-conditions, post-conditions, object invariants in .NET - go here

Share sourcecode between Silverlight and WPF Applications

jimmytr — Wed, 11 Jun 2008 23:49:30 GMT

Sharing code between Silverlight and WPF Applications has been a returning wish from several of the customers in our Microsoft Innovation Center in Denmark. The base class libraries are very similar, but obviously something is missing in the 3-4 MB Silverlight download you just installed on that iMac in your girlfriends officespace... therefore if you use features in .NET that is not supported by the SL BCL sharing is not possible. As you are compiling your projects to a given runtime the binary sharing is not really an option either. That leaves us with source code sharing - which is close to 100% better than no sharing at all.

Code to share typically include Presentation Models, Controllers, Domain Objects, Data Transfer Objects etc.

It is a good idea to start with the lowest denominator (Silverlight) if you have the choice from the beginning of your project. Some limitations may require you to think completely differently than you would normally if you were starting out with the full featureset of WPF (ex. ICommand) - you will eventually run into grayzones and I will leave it up to your judgement to decide when and how much you can/should share.

One way to achieve code file sharing is to use the "Add As Link" in the "Add Existing Item" dialog in Visual Studio (push the little arrow to get to it)

An example is shown below:

Notice the "link" icon on the "MyClass.cs" file in the Silverlight project.

If you have code that is not really shared but nice to keep in the shared file you can make use of the C# preprocessor directives. That sounds like a bad thing to do, but you may have to use different namespaces etc. Silverlight projects actually has a SILVERLIGHT "define" allowing you to include specific code simply by writing:

#if SILVERLIGHT
using System.Windows.Media.Animation;
#endif

You will notice that this is grayed out in the FullCLR project (and obviously the directive #if !SILVERLIGHT may be used in the opposite case)

I have just learned about another way of sharing source files that is less visible in the UI (no "linked icon") but seem to solve the exact same problem.

Any comments and other ideas are welcome - i acknowledge that it is kind of simple but it solves most cases where source code sharing is possible.

Searching...

jimmytr — Wed, 11 Jun 2008 01:43:48 GMT

Unfortunately on g**g** technologies but the idea of a search shell is quite fun - look here

A modern alternative is the Silverlight based search front-end tafiti (not new, but to some people i may be)

Distributed Cache

jimmytr — Tue, 10 Jun 2008 23:55:34 GMT

Just stumbled over a "new" distributed cache CTP from Microsoft - codename Velocity

Having played a bit with NCache in the past i welcome this initiative very much - go have a look

Simple "Sponsors" WebPart (AdRotator)

jimmytr — Tue, 05 Feb 2008 23:22:52 GMT

Here's a very simple webpart that randomly shows pictures from a picturelibrary. The part is configured with the name of a picturelibrary. Pictures should have the Title property set to the URL of the sponsor web site ... very few lines of code solves the problem:

namespace MyWSSParts
{
[Guid("815fbeb7-c1d2-46bb-b5cb-ef3db15c474f")]
public class AdRotatorPart : WebPart
{
public AdRotatorPart()
{
this.ExportMode = WebPartExportMode.All;
}
private string adsLibraryName = string.Empty;
[Personalizable(true), WebPartStorage(Storage.Shared),
WebBrowsable(true), WebDisplayName("Picture Library"),
WebDescription("Library to use")]
public string AdsLibraryName
{
get { return adsLibraryName; }
set { adsLibraryName = value; }
}
protected override void CreateChildControls()
{
base.CreateChildControls();
try
{
if (string.IsNullOrEmpty(adsLibraryName))
return;
SPWeb web = SPContext.Current.Web;
SPList list = web.Lists[adsLibraryName];
if (list == null)
throw new Exception("The Picture Library [" + adsLibraryName + "] could not be found.");
Random rnd = new Random();
int resourceIndex = rnd.Next(list.ItemCount);
SPListItem li = list.Items[resourceIndex];
string webUrl = web.ServerRelativeUrl;
if (webUrl != "/")
{
webUrl = webUrl + "/";
}
Image imgControl = new Image();
imgControl.ImageUrl = webUrl + li.Url;
imgControl.ToolTip = li.Title;
HyperLink hl = new HyperLink();
hl.NavigateUrl = li.Title;
hl.Target = "_blank";
hl.Controls.Add(imgControl);
this.Controls.Add(hl);
}
catch (Exception ex)
{
Label label = new Label();
label.Text = ex.Message;
this.Controls.Add(label);
}
}
}
}

Remember to add it to safecontrols in web.config

Security tips and code clips [german]

jimmytr — Sat, 23 Jun 2007 11:41:00 GMT

ThinkTecture's Dominick Baier has helped MSDN in Germany to create a number of clips and How-To's covering several aspects of security on the .NET platform.

If you remember any german from school I would recommend you point your browser this way

Smart Clients from Greece?

jimmytr — Tue, 05 Jun 2007 10:20:00 GMT

Microsoft Code Name "Acropolis" has finally been released to the public as a technology preview.

Having played with some internal releases it has become clear to me what a huge amount of work the team has put into this technology. I would like to congratulate with this important milestone and will obviously help getting customer feedback.

Features included in Acropolis CTP1 includes:

- Declarative Composition - allows you to declarative program the structure of application components

- Navigation support - manages activation and deactivation of components

- Document Life Time support - manages the life time of a document bject

- Layout Pane - Split style and tab style UI layout that leverages WPF

- Transition Animation - Prepackage transitions built on WPF

... and all these comes with Application Design Time Support!

Go get your copy here and please provide feedback to our hard-working team in Redmond.

Note: The CTP1 requires the Visual Studio Codename "Orcas" to run - get it here

SaaS - SDP

jimmytr — Thu, 10 May 2007 01:48:00 GMT

A couple of my colleagues from across the pond have recently blogged about SaaS and the so-called Service Delivery Platform. Check it out here

ISB - Biztalk Services in the sky

jimmytr — Thu, 26 Apr 2007 17:58:00 GMT

If you haven't done so already I recommend you take a look at our latest Biztalk Services CTP from the Connected Systems Division (http://connectedsystems.spaces.live.com/).

Quite a few people has already commented on this and I will just forward you to some of the links I have found interesting:

http://labs.biztalk.net/

http://blogs.msdn.com/stevemar/

http://blogs.msdn.com/clemensv/archive/2007/04/25/internet-service-bus.aspx

http://www.dennispi.com/

Have Fun!

Writing Test Code with Impersonation

jimmytr — Sat, 14 Apr 2007 22:01:00 GMT

Some of your (unit) tests may be required to run with predefined credentials, and if all your tests should run as one single identity your might as well use the command line runas.exe tool to start your testrunner (or whatever your favorite naming for this is). In some (rare?) occasions you may need to do tests with a large number of different credentials. There is a number of ways to do this and here I will show you two methods: P/Invoke and Windows Communication Foundation (WCF). I don’t feel like explaining a lot today so I’ll just drop you some sample code you can play with.

P/Invoke

using System;

using System.Security.Principal;

using System.Runtime.InteropServices;

using System.Threading;

namespace Test

{

class Program

{

static void Main(string[] args)

{

User u = new User("joe",string.Empty,"P\"ssw0rd");

Thread t = new Thread(DoWorkAs);

t.Start(u);

Console.ReadLine();

}

private static void DoWorkAs(object o)

{

User u = o as User;

//Print user of application

Console.WriteLine(WindowsIdentity.GetCurrent().Name);

IntPtr hToken = IntPtr.Zero;

IntPtr hTokenDuplicate = IntPtr.Zero;

if (Win32.LogonUser(u.UserName, u.Domain, u.Password, 2 /*LOGON32_LOGON_INTERACTIVE*/, 0 /*LOGON32_PROVIDER_DEFAULT*/, out hToken))

{

if (Win32.DuplicateToken(hToken, 2, out hTokenDuplicate))

{

WindowsIdentity windowsIdentity = new WindowsIdentity(hTokenDuplicate);

WindowsImpersonationContext impersonationContext = windowsIdentity.Impersonate();

// domain\username

Console.WriteLine(WindowsIdentity.GetCurrent().Name);

//INVOKE UNIT TEST HERE - or call test controller or whatever you prefer to call it today...

//revert

impersonationContext.Undo();

Console.WriteLine(WindowsIdentity.GetCurrent().Name);

}

if (hToken != IntPtr.Zero) Win32.CloseHandle(hToken);

if (hTokenDuplicate != IntPtr.Zero) Win32.CloseHandle(hTokenDuplicate);

}

public class User

{

public User(string u, string d, string p)

{

Domain = d;

UserName = u;

Password = p;

}

public string UserName;

public string Domain;

public string Password;

}

public class Win32

{

// P/Invoke snask

[DllImport("advapi32.dll", SetLastError = true)]

public static extern bool LogonUser(

string lpszUsername,

string lpszDomain,

string lpszPassword,

int dwLogonType,

int dwLogonProvider,

out IntPtr phToken);

[DllImport("advapi32.dll", SetLastError = true)]

public extern static bool DuplicateToken(IntPtr ExistingTokenHandle, int

SECURITY_IMPERSONATION_LEVEL, out IntPtr DuplicateTokenHandle);

[DllImport("kernel32.dll", SetLastError = true)]

public static extern bool CloseHandle(IntPtr hHandle);

}

(Note: In this example I could have used the System.Net.NetworkCredential class instead of the homemade User class)

WCF

using System;

using System.ServiceModel;

using System.Security.Principal;

using System.Threading;

using System.Net;

namespace TestWCF

{

[ServiceContract(Namespace = "NotDefault")]

public interface IImpersonateTest

{

[OperationContract]

void RunAsTest();

}

public class ImpersonateTest : IImpersonateTest

{

[OperationBehavior(Impersonation = ImpersonationOption.Allowed)]

public void RunAsTest()

{

Console.WriteLine(

string.Format("Inside a WCF Service - caller: {0}",

WindowsIdentity.GetCurrent().Name));

//INVOKE UNIT TEST HERE - or call test controller or whatever you prefer to call it today...

}

class Program

{

static string _address = "net.pipe://localhost/ImpersonateTest";

static NetNamedPipeBinding _binding = new NetNamedPipeBinding();

static void Main(string[] args)

{

Thread t = new Thread(Server);

ManualResetEvent mre = new ManualResetEvent(false);

t.Start(mre);

mre.WaitOne();

EndpointAddress epa = new EndpointAddress(_address);

ChannelFactory<IImpersonateTest> factory = new ChannelFactory<IImpersonateTest>(_binding,_address);

factory.Credentials.Windows.ClientCredential = new NetworkCredential("joe", "P\"ssw0rd", String.Empty);

IImpersonateTest proxy = factory.CreateChannel();

proxy.RunAsTest();

((ICommunicationObject)proxy).Close();

Console.WriteLine("Press <ENTER> to exit.");

Console.ReadLine();

t.Abort();

t.Join();

Console.WriteLine("Done...");

}

static void Server(object o)

{

ManualResetEvent mre = o as ManualResetEvent;

ServiceHost sh = new ServiceHost(typeof(ImpersonateTest));

try

{

sh.AddServiceEndpoint(typeof(IImpersonateTest), _binding, _address);

sh.Authorization.ImpersonateCallerForAllOperations = true;

sh.Open();

mre.Set(); //Ready - client can continue

Console.WriteLine("Service host opened");

Thread.Sleep(System.Threading.Timeout.Infinite);

}

catch (ThreadAbortException)

{

//Abort is called at some point.

}

finally

{

sh.Close();

Console.WriteLine("Service host closed");

}

EntLib 3.0 Released

jimmytr — Sun, 08 Apr 2007 10:27:00 GMT

The P&P team has finished the third major release of the enterprise library. See Tom's post for more information. Try the new WCF integration with logging, exception handling and validation application blocks. Download from MSDN.

Updated VSTS Guidance Available

jimmytr — Thu, 05 Apr 2007 21:08:00 GMT

The P&P team has updated guidance related to Visual Studio Team System on Codeplex

SaaS Vocabulary

jimmytr — Tue, 27 Mar 2007 02:25:00 GMT

I have found myself explaining SaaS a few times the past weeks and recently found the WIKI pages: http://en.wikipedia.org/wiki/Software_as_a_Service

Also Lars Fløe Nielsen from SiteCode has a series of good posts on SaaS from the ISV perspective.

And as a final link on SaaS from me this time: saasblogs.com

XmlSerialization snippet

jimmytr — Sat, 24 Mar 2007 17:39:00 GMT

I keep writing this code - now I can find it on my blog in the future :-)

public static class StringXmlSerializer

{

public static string Serialize<T>(T obj)

{

XmlSerializer s = new XmlSerializer(typeof(T));

StringBuilder sb = new StringBuilder();

StringWriter sw = new StringWriter(sb);

s.Serialize(sw, obj);

return sb.ToString();

}

public static T Deserialize<T>(string str)

{

XmlSerializer s = new XmlSerializer(typeof(T));

StringReader sr = new StringReader(str);

return (T)s.Deserialize(sr);

}

WF in IIS Hosted WCF Service

jimmytr — Mon, 19 Mar 2007 12:38:00 GMT

Hosting Workflow in WCF is described in the before mentioned article by Jeremy Boyd. In the article it is shown how to create an extension class for Workflow, and add this to the ServiceHost Extension collection. The code presented in the article is something like:

using (ServiceHost serviceHost = new ServiceHost(new ExpenseService()))

{

WfWcfExtension wfWcfExtension = new WfWcfExtension("WorkflowRuntimeConfig");

serviceHost.Extensions.Add(wfWcfExtension);

serviceHost.Open();

// block the process at this point, for example

Console.ReadLine();

serviceHost.Close();

}

While this works perfectly for a console server you may need to host the service in IIS at a later point in your development. As the example above show we need to add the extension to the ServiceHost at some point. The suggested way of doing this is to subclass the ServiceHost and add your service extensions in the OnOpening method. Example:

public class WFServiceHost : ServiceHost

{

public WFServiceHost(Type t, params Uri[] baseAddresses) : base(t, baseAddresses){}

public WFServiceHost(object singletonInstance, params Uri[] baseAddresses) :

base(singletonInstance, baseAddresses) {}

public WFServiceHost() : base(){}

protected override void OnOpening()

{

WfWcfExtension wfWcfExtension = new WfWcfExtension("WorkflowRuntimeConfig");

Extensions.Add(wfWcfExtension);

base.OnOpening();

}

IIS hosting of WCF Services is done adding a .svc file to your and in order to use your specialized servicehost you must provide a ServiceHostFactory that creates and instance of your servicehost:

public class WFServiceHostFactory : ServiceHostFactory

{

protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)

{

return new WFServiceHost(serviceType, baseAddresses);

}

The .svc file should specify this as:

<%@ServiceHost language="c#" Factory="WorkflowServiceHost.WFServiceHostFactory" Service="SHP.ProvisioningService" %>