Generic.xaml in Silverlight Beta1 for WPF developers

I woke up early this morning and decided to play around with Silverlight…. I love Silverlight it makes me feel like I am developing in WPF yet Cross Browser and Cross Platform…. can it get better than that???

Yet, this morning I had to swear a bit !

Generic.xaml xmlns

I was building a Silverlight custom control (as usual that the first thing I try out in a new platform ) and I found a post that helped me a lot. The first problem that I found was Visual Studio does not have a template for a ResourceDictionary for Silverlight.

As you all know in order to build a custom control Generic.Xaml is one of the most important things to do. Generic.Xaml would contain the UI of the custom controls.

Yet thanks to the post I just mentioned I got through this by create a Text File (naming it generic.xaml) and setting the Build Action to Resource. You must also clear all other fields… something like this

I said ok, I have the generic.xaml all set up now all I need to do is to create a Style for the control that will act as the UI for my new Custom control. First thing I did was to create an xmlns declaration so that I can style my control. something like this

xmlns:local="clr-namespace:SilverlightApp"

As you can see I did not add the assembly part in this because I said since the generic.xaml is in the same project of the control class I would not need it. At least that is what you would do if you are a WPF developer. But guess what I ran the application and BAMMMM!!! I got a AG_E_UNKNOWN_ERROR. This is a nice error to get in 7 o clock in the morning

I started looking around to try and translate this error and I found a very helpful post. Yet still, I could not find the source of the problem… Then I tried something out, just to say that I tried it… basically I added the assembly part in my generic.xaml xmlns declaration… something like this

xmlns:local="clr-namespace:SilverlightApp;assembly=SilverlightApp"

And Guess what… It worked!!!

For me this is quite crazy because I never had to do such a thing in WPF. Actually if you try to do that in WPF you would start getting an error because the generic.xaml is in the same assembly of the control you are trying to reference. But anyway, Silverlight is still BETA and I am more than sure that this will be fixed in the near future.

The ResourceDictionary.MergedDictionaries

Ok so with the xmlns problem fixed, I was hoping to find no other surprise but after a minute I got another one!!!

Usually when one is building a controls library you would create a ResourceDictionary for each control so that the generic.xaml would not get cluttered. And then you merge all dictionaries in the generic.xaml by using the ResourceDictionary.MergedDictionaries something like this…

<ResourceDictionary.MergedDictionaries>

   <ResourceDictionary Source="/AvalonControlsLibrary;component/Themes/Brushes.xaml"/>

   <ResourceDictionary Source="/AvalonControlsLibrary;component/Themes/DatePicker.xaml"/>

</ResourceDictionary.MergedDictionaries>

But guess what. There is no such thing YET in silverlight
so you have to put all the resources for the controls in the generic.xaml. I didn’t find a workaround for this yet but I will update this post if/when I do.

Last word

Silverlight is really cool. Don’t let small things like this get in the way. I am more than sure that issues like this will be fixed in the near future…. I remember when WPF was still in Beta there where similar things. The only difference with Silverlight is that there is already WPF and people expect that Silverlight has the same capabilities. Eventually this will happen but for now we must wait

Last 2 words – Silverlight Rocks!

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• Themes/generic.xaml