You are developing an application by using Silverlight 4 and Microsoft .NET Framework 4. You create a new user control in the application. You add the following XAML fragment
to the control:

<StackPanel KeyDown=”App_KeyDown” Orientation=”Vertical”>
<TextBox x:Name=”firstName” />
<TextBox x:Name=”lastName” />
<TextBox x:Name=”address” />
</StackPanel>

You add the following code segment in the code behind file of the control. (Line numbers are included for reference only.)

01 private void App_KeyDown(object sender, KeyEventArgs e)
02 {
03
04 }
05
06 private void FirstAndLastNameKeyDown()
07 {
08 …
09 }

You need to ensure that the First And LastName KeyDown method is invoked when a key is pressed while the focus is on the firstName or lastName TextBox controls. You also need to ensure that the default behavior of the controls remains unchanged.
Which code segment should you add at line 03?

You have a Silverlight application that connects to a Windows Communication Foundation (WCF) service. The WCF service is not hosted on the originating domain. When you call the WCF service, you receive the following error: “Page Not Found.” You need to resolve the error. What should you do?

You are developing a Silverlight 4 application named MySilverlightApplication.xap. The application is hosted on a Microsoft ASP.NET Web page named default.aspx by using the following HTML markup. (Line numbers are included for reference only.)

01 <object data=”data:application/xsilverlight2,”type=”application/xsilverlight2″ width=”100%” height=”100%”>
02 <param name=”source” value=”ClientBin/MySilverlightApplication.xap”/>
03
04 </object>

The ASP.NET application has two string variables named strPrimaryEmail and strSecondaryEmail. You need to ensure that both variables are passed to the Silverlight application. Which HTML markup should you insert at line 03?

You are developing an application by using Silverlight 4 and Microsoft .NET Framework 4.
You add a BackgroundWorker object named worker to the application. You also add a CheckBox control named checkBox and a TextBlock control named statusTextBlock.
You add the follo wing code segment. (Line numbers are included for reference only.)

01 public MainPage()
02 {
03 InitializeComponent();
04 worker.WorkerReportsProgress = true;
05 worker.DoWork += new DoWorkEventHandler(worker_DoWork);
06 worker.ProgressChanged += new ProgressChangedEventHandler(worker_ProgressChanged);
07 }
08 private void worker_DoWork(object sender, DoWorkEventArgs e)
09 {
10 for (int i = 0; i < 100; i++) {
11 bool isChecked = checkBox.IsChecked.HasValue && checkBox.IsChecked.Value;
12 ExecuteLongRunningProcessStep(isChecked);
13 worker.ReportProgress(i);
14 }
15 }
16 private void worker_ProgressChanged(object sender, ProgressChangedEventArgs e)
17 {
18 statusTextBlock.Text = e.ProgressPercentage + “%”;
19 }

You attempt to run the application. You receive the following error message: “Invalid crossthread access.”
You need to ensure that worker executes successfully. What should you do?

You are developing a Silverlight 4 application named Contoso.Accounts.Ui. The application uses a Silverlight library named Contoso.Ui.Common. You use application library caching to reduce the size of the XAP file by deploying Contoso.Ui.Common as a separate zip file. You create the following XML file.

<xml version=”1.0″ >
<manifest xmlns:xsi=”http://www.w3.org/2001/XMLSchemainstance” xmlns:xsd=”http://www.w3.org/2001/XMLSchema”>
<assembly>
<name>Contoso.UI.Common</name>
<version>1.0.0.0</version>
<publickeytoken>5ca45a28299b8a35</publickeytoken>
<relpath>Contoso.UI.Common.dll</relpath>
<extension downloadUri=”Contoso.UI.Common.zip” />
</assembly>
</manifest>

You need to ensure that the Contoso.Ui.Common library will be packaged as a separate zip file.
What should you do?