Accessing the UI thread in Silverlight

I’m creating a separate class where I want to move all related Client Object Model (COM) code.

In my case for the COM code to work it must update the UI thread. To accomplish this I had to move the reference from the main page, which was apparently passing through the Deployment object, to explicitly calling the Deployment object.

So in the case of the main page or I suspect any xmal pages code behind use this line of code in the ClientRequestSucceededEventHandler method:

this.Dispatcher.BeginInvoke(updateUI);


For separate classes to gain access to the UI thread use this line of code in the ClientRequestSucceededEventHandler method:

Deployment.Current.Dispatcher.BeginInvoke(updateUI);



Reference:
http://www.go4answers.com/Example/error-invalid-cross-thread-access-48335.aspx
Using Silverlight Object Model: http://msdn.microsoft.com/en-us/library/ee538971.aspx

Libraries for Client Object Model

Ok this falls in to information I’ve had to look-up a couple times now. So I’m posting this to my blog for quick reference in the future.

Libraries required for SharePoint development using Client Object Model

The two files for Silverlight are:
Microsoft.SharePoint.Client.Silverlight.dll
Microsoft.SharePoint.Client.Silverlight.Runtime.dll

They can be located on the server at %ProgramFiles%\Common Files\Microsoft Shared\Web Server Extensions\14\TEMPLATE\LAYOUTS\ClientBin

For sandbox solutions you need:
Microsoft.SharePoint.Client.dll
Microsoft.SharePoint.Client.Runtime.dll

These are located on the server at %ProgramFiles%\Common Files\Microsoft Shared\web server extensions\14\ISAPI

Getting the URL Parameter Using C#

As I’ve been working with the SharePoint COM API in Silverlight more things that were really hard to do or nearly impossible to do with SharePoint Designer (SPD) have become easier. One of the first things I need to do was link the Silverlight applications and my existing pages together which I felt was really easy to do by passing Query String Parameters.

This is really easy to do in C# with the Windows.Browser namespace.

Here is the method I use to accomplish this.

private string getURLParam(string key)
{
string value = "";
HtmlPage.Document.QueryString.TryGetValue(key, out value);
return value;
}

Now I can provide whatever key I would like to consume, in my case a row ID so I know which record to query in the SharePoint list.