Can a DataTemplate in XAML be associated with a nested class?
I am working on a MVVM application, and I have run into a data template problem. I have a view model providing a collection of other view models for an items control. These items are part of a hierarchy defined as nested classes in the outer view model. I have been unable so far to create a mapping in XAML to reference the inner nested class.
Here is the class hierarchy (simplified for brevity):
public class MainViewModel
{
public class A
{
}
public class B : A
{
}
public class C : A
{
}
public ObservableCollection<A> Items
{
get;
set;
}
}
In XAML, I'm trying to map a DataTemplate to types B and C, but I cannot fully qualify the nested class name.
<ItemsControl ItemsSource="{Binding Path=Items}">
<ItemsControl.Resources>
<DataTemplate DataType="{x:Type ns:BracingViewModel.B}">
<Grid>
....
</Grid>
</DataTemplate>
<DataTemplate DataType="{x:Type ns:BracingViewModel.C}">
<Grid>
....
</Grid>
</DataTemplate>
</ItemsControl.Resources>
</ItemsControl>
The problem : the references to the nested classes show up as a build error in the XAML. I get the following:
Error 5 Cannot find the type 'ns:B'. Note that type names are case sensitive. Line...
Error 5 Cannot find the type 'ns:C'. Note that type names are case sensitive. Line...
If I move the A,B,C class hierarchy outside the MainViewModel class (i.e. to the namespace level), this works fine.
As a general habit, I try to keep classes relevant to the view model defined as nested classes within it, but that leads me to this issue.
So, my question : is it even possible to associate a DataTemplate with a nested class? If so, how is that done in the XAML portion?
Thanks in advance... Joe
This works for me:
<ItemsControl ItemsSource="{Binding Path=Items}">
<ItemsControl.Resources>
<DataTemplate DataType="{x:Type ns:MainViewModel+B}">
<Grid Background="Blue"
Width="30"
Height="30">
</Grid>
</DataTemplate>
<DataTemplate DataType="{x:Type ns:MainViewModel+C}">
<Grid Background="Chartreuse" Width="30" Height="30">
</Grid>
</DataTemplate>
</ItemsControl.Resources>
</ItemsControl>
In other words, just change the .
to +
in the x:Type
markup extension
credit to: this thread
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