ASP.NET Debugging : ADO.NET

Silverlight RIA calling Stored Procedures that don’t return tables

Tom — Thu, 07 May 2009 17:07:07 GMT

There are times where you want to use a stored procedure that doesn’t return just normal rows out of a database. One classic example is if you are doing Full-Text Searching and want to return the Rank.

The first step to doing this is the get your stored procedures exposed in the ADO.NET Entity Data Model. Instead of going through the steps for doing that here, I’ll just point you to a great post by Julie Lerman on her blog: Implement SELECT Stored Procedures that return miscellaneous data in CTP2 of EF Designer.

After following those steps, you will have the stored procedures all ready to be called from the Entity Data Model. You can then use these stored procedures from ASP.NET, ASP.NET MVC, or anything else that can consume the Entity Data Model.

One side note, if you use the “Update Model from Database…” feature on your Entity Model, it will destroy the store layer tables that you created from Julie’s post. If that happens, just recreate them again.

Now to get this to work from Silverlight using RIA, there is another step that needs to be done. You need to get these stored procedures exposed in your Domain Service. One way to handle doing that is to create functions in the Domain Service like the following for each of them. Assume you have a stored procedure called SearchData and it takes a string as input to seach for in the database. You can create a function in the Domain Service like:

        1: public IQueryable<SearchDataTable> GetSearchData(String SearchString)

       2: {

       3:     return Context.SearchData(SearchString).AsQueryable();

       4: }

When you compile this, it will create a client side function called LoadSearchData that takes a string as input. Then you can call this just like you load any other data in Silverlight RIA:

       1: public void Searching(String search)

       2: {

       3:     if (String.IsNullOrEmpty(search))

       4:     {

       5:         return;

       6:     }

       7:  

       8:     context.LoadSearchData(search);

       9:     context.Loaded += new EventHandler<System.Windows.Ria.Data.LoadedDataEventArgs>(context_Loaded);

      10: }

      11:  

      12: void context_Loaded(object sender, System.Windows.Ria.Data.LoadedDataEventArgs e)

      13: {

      14:     var context = sender as MyDomainContext;

      15:     foreach (SearchDataTable searchData in context.SearchDataTable)

      16:     {

      17:         ... do stuff with the data ...

      18:     }

      19: }

Notice that I am hooking up to when the context is finished being loaded so that I know the data has been populated.

ASP.NET Troubleshooting

Tom — Tue, 24 Mar 2009 19:31:03 GMT

So with how long ASP.NET has been out for now, I am really curious to know how people go about tracking down issues in their project.

I’d like to know things like:

How do you know there is a problem
What tools do you use to confirm that the problem really is a problem
How do you gather data about the problem
How do you determine if the problem is your code or something else (like the network, hard drive failure, etc)
If the problem is your code, how do you ensure your fix resolves the problem (how do you test the fix)

If there are any others, I’d also like to hear them.

Also, if you do anything in the Cloud now, I’d love to hear how you troubleshoot that. And it can be from any cloud service provider.

And have any of these things changed with some of the new ways to program that have come out. For example, AJAX, MVC, Silverlight, IE8, jQuery, etc.

The PDC this year…

Tom — Mon, 29 Sep 2008 13:00:00 GMT

Not sure how many people are planning on attending the PDC (Professional Developers Conference) this year, but it is going to be a fantastic conference.

We announced some huge announcements on the PDC web site. http://www.microsoftpdc.com/

We have a major lineup of executive keynote speakers representing most of the core Microsoft businesses.
We’ll have 20+ Windows 7 sessions, and we’ll be giving out the Win7 bits.
We also announced our in-depth symposia sessions including parallel computing and S+S.

If you have any questions about the PDC, feel free to check out the site listed above, or you can Ask the Brain.

The conference runs from October 27th to October 30th with the pre-conference on October 26th. You can see the full agenda here.

We have also just announced that all partners and customers attending the PDC will receive a very special gift this year: a 160GB external USB2 hard drive with all of the bits! That is a very cool gift and very useful as well. I’d love to hear if anyone is going or thinking about going to the PDC!

Slow performance of a GridView inside an UpdatePanel

Tom — Mon, 15 Sep 2008 13:00:00 GMT

Here is an interesting problem we ran into recently. The customer had a large GridView that was being updated by AJAX inside on UpdatePanel and seeing bad performance.

The reason is that the Client-Side Javascript has to walk the entire DOM of the Content of the UpdatePanel to tear down the HTML DOM as the Page goes through an Asynchronous update.

First Solution

To alleviate the Expensive Stack Walks to destroy DOM Elements and its related Time Delay, the developers suggested that we remove the Unnecessary payload from the DOM of the UpdatePanel during an Asynch Postback.

The Way you would implement this is to:

1. Hook up an Event handler to the beginRequest Event .

EX:

<script language ="javascript" type ="text/javascript">
  Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(clearDisposableItems)
</script>

2. Destroy an DOM Elements that you don’t want the Framework to tear down by tearing it down manually.

EX:

function clearDisposableItems( sender , args ) {
  if (Sys.Browser.agent == Sys.Browser.InternetExplorer ) {
    $get('<%=GridViewID.ClientID%>').tBodies[0].removeNode(true);
  } else {
    $get('<%=GridViewID.ClientID%>').innerHTML="";
  }
}

This gave us a slight decrease in the time taken for async Updates, about 3 seconds less. But, we are still far away from the optimal turn-around time of a few seconds.

In a sample that I setup on my machine using about 500 rows in a GridView, the turn-around times were in the order of sub-seconds when the GridView had text labels instead of textboxes.

When I changed the text labels to textboxes, there was an exponential jump in the time taken to process the Form even before the request was submitted to the Server.

Sub-second response times changed to 25 seconds!!

The main reason for this slow-down is due to the number of Controls that are present in the Grid. We cannot optimize the Javascript to give good performance in this scenario.

Alternative methods

So what can we do if we need a GridView with controls? Well, the best suggestions are:

Enable paging to allow the control to stay smaller but still give all the information required.
Change the UI to allow for an optimal number of rows that give acceptable performance.

Inserting a dynamic column into a DataGrid and sorting by it

Tom — Wed, 06 Aug 2008 13:00:00 GMT

We recently had a customer that wanted to sort a dynamic column in a DataGrid and so I thought it may be something that others would like to be able to do.

You get your data for your dynamic column and then do something like below to insert it into an existing DataTable in a DataSet:

     Dim dc as new DataColumn

    dc.DataType = System.Type.GetType("System.String")

    dc.Caption = "DynColumn"

    dc.ColumnName = "DynColumn"

    vServersSet.Tables(0).Columns.Add(dc)

    For I = 0 To vServersSet.Tables(0).Rows.Count - 1

        Dim get_value As String

        get_value = GetData(I)

        vServersSet.Tables(0).Rows(I).Item("DynColumn") = get_value

    Next

Now apply sorting:

    vServersSet.Tables(0).DefaultView.Sort = "DynColumn Desc"
  

This way we can sort on our dynamic column in our grid. To point the Grid to the table, just using something like:

    DataGrid1.DataSource = vServersSet.Tables(0)

    DataGrid1.DataBind()