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European Silverlight 5 Hosting - Amsterdam :: Using MVVM to Show Busy Indicator in Silverlight

clock February 25, 2013 05:05 by author Scott


When using Silverlight, everything is asynchronous. It seems to be the trend, the same goes for Windows 8. This means that you will need to inform the user about progress in the background.

Silverlight uses the BusyIndicator for this behavior. Using MVVM, it might be a bit harder to implement the BusyIndicator in a correct way, but Catel provides the IPleaseWaitService for years which can be mocked easily during test scenarios.

However, it didn’t support a busy indicator per view yet. This fact has changed today, as you can see in the screenshot below:

A long requested feature in Catel was the support for tags in the ServiceLocator. The ServiceLocator is the IoC solution that Catel provides by default. A customer of Catel recently required the busy indicators to show up per view. I thought a bit about it and this could be solved by the recently (read: this week) introduction of the tags in the ServiceLocator.

Setting up the views

The view is responsible for registering the service. This can easily be done using the Catel user controls. Create a view like you always do, then use the following code-behind:

   1:  protected override void OnViewModelChanged()
   2:  {
   3:      var serviceLocator = ServiceLocator.Default;
   5:      var viewModel = ViewModel;
   6:      if (viewModel != null)
   7:      {
   8:          serviceLocator.RegisterInstance(typeof (IPleaseWaitService), new PleaseWaitService(this), viewModel);
   9:      }
  10:  }

This code will be executed when the ViewModel property of the control changes. The view registers a view specific instance of the PleaseWaitService service in the ServiceLocator. It uses the new view model as tag so that will be used to distinguish the services.

Setting up the view models

The view model can retrieve the PleaseWaitService very easily because the tag is itself. To show the view specific please wait service, use this code:

   1:  var pleaseWaitService = GetService<IPleaseWaitService>(this);
   2:  pleaseWaitService.Show();

To hide the window again, use this code:

   1:  var pleaseWaitService = GetService<IPleaseWaitService>(this);
   2:  pleaseWaitService.Hide();

Customizing the PleaseWaitService

Customizing the please wait service is very, very easy. Just override the class like this:

   1:  public class MyCustomPleaseWaitService : PleaseWaitService
   2:  {
   3:      protected override FrameworkElement CreateBusyIndicator()
   4:      {
   5:          var busyIndicator = new MyBusyIndicatorControl();
   7:          busyIndicator.SetBinding(System.Windows.Controls.BusyIndicator.BusyContentProperty, new Binding("Status"));
   8:          busyIndicator.SetBinding(System.Windows.Controls.BusyIndicator.IsBusyProperty, new Binding("IsBusy"));
  10:          return busyIndicator();
  11:      }
  12:  }

The base implementation will automatically take care that the data context is updated and that the control is centered as required.


European Silverlight Hosting - Amsterdam :: How to Enable Dynamic Compression in IIS 7/7.5

clock February 18, 2013 07:47 by author Scott

In this tutorial I will show you how to enable dynamic compression in IIS 7. For other post of dynamic compression, please just see our last post.

You’ll see this error message when you haven’t setup dynamic compression on your IIS:

“The dynamic content compression module is not installed.”

Ok, let’s start the tutorial:

1. Open server manager

2. Roles --> IIS

3. Role Services (scroll down) --> Add Role Services

4. Add desired role (Web Server --> Performance > Dynamic Content Compression)

5. Wait till finish.

To enable this feature, here are the steps:

1. Open server manager

2. Roles --> Web Server (IIS) --> Internet Information Services (IIS) Manager

3. Then, go to your site --> your website

4. IISà compression

And dynamic compression has been enable on your server. Hope this tutorial is interesting.


European Silverlight Hosting - Amsterdam :: Dynamic Compression in IIS 7

clock February 5, 2013 10:17 by author Scott

This is the question from one of our clients. The client insisted on returning large datasets, well in excess of 10,000 records. I will leave the story of figuring out how to properly specify the MaxItemsInObjectGraph service behavior attribute for some other post, but the other problem I was constantly aware of, was the data size returned from the server. With all filters set to max, the data set was well in excess of 30 megabytes. This might not be a big problem on a local network, but if some of your users are located across the big pond called Atlantic, you might want to compress your data before shipping it over.

Now, the IIS 7 console only allows you to enable or disable static compression, but it does not let you control which dynamic types are being compressed as well as the level of compression desired for each content type.

The command you are supposed to use instead is AppCmd.exe located in C:\Windows\System32\inetsrv directory.

So here are three sample commands that helped me reduce the size of my WCF RIA Domain Service's binary response by 80%. Needless to say I was pleasantly shocked.

Enable compression on WebDevel webserver (when you have multiple servers and want to do it specifically for each)

C:\Windows\System32\inetsrv>Appcmd.exe set config "WebDevel" -section:urlCompression -doStaticCompression:true -doDynamicCompression:true

Add mime-type application/msbin1 to dynamic compression list (service wide)

C:\Windows\System32\inetsrv>Appcmd.exe set config -section:system.webServer/httpCompression /+"dynamicTypes.[mimeType='application/msbin1',enabled='True']" /commit:apphost

Set compression levels for static and dynamic content (service wide)

C:\Windows\System32\inetsrv>Appcmd.exe set config -section:httpCompression -[name='gzip'].staticCompressionLevel:9 -[name='gzip'].dynamicCompressionLevel:5

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