Silverlight & Blend try and encourage you to separate styles and structure in much the same way as you should with HTML and CSS. However, Blend can be confusing as it will offer up some properties to be changed but “hide” others. One example of this is the seemingly simple task of changing the colour of the text in a button. You’d be forgiven for thinking you can select the button and directly edit the foreground colour since the background is available. You must ignore this temptation, if you don’t attempt to make style changes directly to the structure (control) then you’ll avoid a lot of confusion. I’ve created a little tutorial to show one way of solving this;

1. Create a new project in Blend and accept the defaults.
   
2. Add a button
   
3. Select the button, hint using the control tree is often more reliable, right-click and choose Edit Templatate->Edit a Copy. To promote separation I recommend saving the style to the Application. You should give the style a good name, but I’ll be naughty and leave it at ButtonStyle1
   
4. You’ll now find yourself in the Template for the button. Ignore this and return the MainPage.xaml (there is a quicker way but lets keep things simple). Now you want to change the colour of the button, so you need to edit the buttons style. Select the Resources tab and click the button to edit ButtonStyle1
   
5. Now switch back to the Properties tab and you can change the Foreground (remember to drag the little colour select from the bottom left of the selector).
   
6. All done.

So the “take home” from this is don’t make style changes directly to your controls always look at changing the separate style xaml, not only will you have better separation but you’ll avoid a lot of frustration when trying to find the property you want to change.

Had some fun today with code signing some macro's in Excel. Applying a code signing certificate is very easy, simply go to the visual basic editor, tools->Signing and you're away. The problem is creating the correct type of certificate in the first place.

My sys admins provided with a p7b certificate. So I installed that, but it didn't show in VBs available certificates. So I thought I'd better try and understand what was going on. In turns out that I need a pfx certificate and a p7b is just part of formula for creating such a beast. You need the private key used to create the original certificate together with the p7b;

pvk2pfx -pvk privateKey.pvk -spc codeSignCert.p7b -pfx actualCodeSign.pfx -po myPassword -f

That will challenge you for the password used to create the original certificate but will produce required pfx file. Now just install that and it should be available for signing

Vista on Parallels 3 was good, Vista on Parallels 4 was terrible. So I wasn't too bothered in ditching my Vista VM and installing Windows 7, even though it's only marked as 'experimental'. Well so far it's been as good as P3, so I'm very happy with it. Don't know where the blame falls for P4+Vista but P4+Win7 is worth having.

I’ve been working on a Silverlight project that where the SL application is used within an authenticated ASP.net site. During my testing I found a problem where using Silverlight 3’s Out-Of-Browser feature seem to lose the session token between calls to the site, i.e. I could logon but the next call would fail as if the user had not logged on. After a couple of Twitter conversations it became apparent that it should work. So I decided to take my testing back to basics, so first off can a Silverlight application use ASP session state?

1. Create a basic Silverlight application – create a Silverlight application with a web project to host it

2. Create a basic web service – with the web project selected add a new Silverlight WCF service, called SessionTest.svc
   

3. Implement some very simple interactions with the Session State
   

   [ServiceContract(Namespace = "")]

       [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

       public class SessionTest

       {

           [OperationContract]

           public void SetState(string value)

           {

               // Add your operation implementation here

               HttpContext.Current.Session["TestState"] = value;

               return;

           }

    

           [OperationContract]

           public string GetState()

           {

               // Add your operation implementation here

               return (string)HttpContext.Current.Session["TestState"];

           }

       }

4. Add a Service Reference from your Silverlight application to your service, add appropriate using statements to your code-behind.

5. Create some simple controls in your Silverlight application
   
   

   <StackPanel>

       <StackPanel Orientation="Horizontal">

           <Button x:Name="ButtonGetState"  Content="Get State" Click="ButtonGetState_Click" Width="60" ></Button>

           <TextBlock x:Name="TextBlockCurrentState" Width="100"></TextBlock>               

       </StackPanel>

       <StackPanel Orientation="Horizontal">

           <TextBox x:Name="TextBoxNewState" Text="" Width="100"></TextBox>

           <Button x:Name="ButtonSetState" Content="Set State" Click="ButtonSetState_Click" Width="60"></Button>

       </StackPanel>

   </StackPanel>

6. Add code to the Silverlight application to communicate with the Service
   
   

   private void ButtonGetState_Click(object sender, RoutedEventArgs e)

           {

               SessionTestClient client = new SessionTestClient();

               client.GetStateCompleted += (object completedSender, GetStateCompletedEventArgs completedE) =>

                   {

                       if (completedE.Error == null)

                       {

                           TextBlockCurrentState.Text = completedE.Result;

                       }

                   };

               client.GetStateAsync();

           }

    

           private void ButtonSetState_Click(object sender, RoutedEventArgs e)

           {

               SessionTestClient client = new SessionTestClient();

               client.SetStateCompleted += (object completedSender, AsyncCompletedEventArgs completedE) =>

                   {

                       if (completedE.Error == null)

                       {

                           TextBlockCurrentState.Text = "";

                       }

                   };

               client.SetStateAsync(TextBoxNewState.Text);

           }

7. Run the code, you should see that after you set a value you can retrieve the same value.

So we now know for sure that we can communicate with ASP.net and share the session state with the page. If you make the Silverlight application OOB (select project properties and check the OOB box) you’ll see that it continues to work without any problems. So this is good news, all I have to do now is track down why it isn’t working in my real application.