Building Custom Controls on top of WinRT in C#

Question

I note that in the Visual Studio 11 express edition developer preview, there is a template for creating a custom control in C++ but not C#.  Does that mean that custom controls now need to be developed in C++?  Is there (or will there) be a way to do this in C#?

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Cameron Peters

Answer 1

Hi Cameron.  The template in C++ is a component, not a control.  The same thing is in C# as well (class library).  You would need to add a resource dictionary (generic.xaml) for which we don't have an item template for in this release, but it is the same as the Silverlight one.  We've got a few questions on this area, so as soon as I can I'll try to post a sample of how to do this.

Short answer: there is a way to do this in C# and it will improve over time.

Answer 2

Tim,

Thanks... I look forward to some examples.  Does that mean we can descend from the WinRT implemented Panel control in C#?  How will the dependency properties work across this boundary.  How is memory handled?  Does WinRT use a malloc / release model or is WinRT memory somehow garbage collected?

... looks like my decision not to registor for Build until the agenda got posted was a mistake.... :(  I have lots of questions that may have been answered in the chalk talks but sadly those videos won't be posted...

~ Cameron

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Cameron Peters

Answer 3

Yes, you can descend from the WinRT implemented Panel in C# (and for example override MeasureOverride), you can descend from Control (and for example override OnApplyTemplate), etc.

WinRT objects control their lifetime with AddRef/Release, but when you're programming in C# you don't see it; GC takes care of the ref counting.

Dependency properties go across the boundary when you call DependencyObject.SetValue/GetValue etc.  You can pass a WinRT object as a property value or a non-WinRT object.  From you C# code you don't see the difference.

- Mike

 

Answer 4

Mike --

Thanks... this is exactly what I needed to know.  How is there a performance hit to crossing the boundary?

~ Cameron

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Cameron Peters

Answer 5

Hi Tim

If I create a WinRT control using C#, can I use it in 'flavors' of Metro apps (C++, HTML, C#, VB)?

Or are there differebt 'kinds' of WinRT controls, one for C#/VB/C++ and one for HTML/js?

Probably a dumb question, but I would love to develop only one set of controls and be able to use them in all kinds of apps... 

 

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bernardo castilho

Answer 6

UI components can be shared between amongst languages that use XAML for rendering (C++/VB/C#) but cannot be shared with the apps that use HTML for rendering.  If you create WinRT components that don't have UI-related dependencies, they can also be shared with HTML/JS apps.

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Robert Levy

Answer 7

where is the sample?

Answer 8

"... I'll try to post a sample of how to do this..."

 

I desperately need a sample of how to create a custom control in C#. Any help would be appreciated.

Answer 9

Here is the source for two relatively simple WinRT C#/XAML custom controls: http://panview.codeplex.com/ and http://charmflyout.codeplex.com/.  

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John Michael Hauck