Geek asks and answers

How to enable ContentControl ContentTemplateSelector in design mode?

Why can't I enable ContentControl ContentTemplateSelector in design mode?
(While working, it works)
Constructor (VS2010) shows an exception:

System.Reflection.TargetInvocationException The exception was caused by the target call.

and

The System.NullReferenceException reference object is not set to an instance of the object.

XAML:

<Window.Resources>
    <DataTemplate x:Key="Temp1">
       <TextBox TextWrapping="Wrap" Text="1" Height="20" Width="Auto"/>
    </DataTemplate>

    <local:TemplateSelector x:Key="mySelector"/>
    <Grid>
       <ContentControl ContentTemplateSelector="{StaticResource mySelector}">
          <ContentControl.Content>
               1
          </ContentControl.Content>
       </ContentControl>      
    </Grid>
 </Window.Resources>

WITH#:

    public class TemplateSelector : DataTemplateSelector
    {
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
             //int num = int.Parse(item.ToString());
             Window win = Application.Current.MainWindow;
             return win.FindResource("Temp1") as DataTemplate;//load template based on num...
         }

    }
+3
source share
2 answers

HB matters Application.Current.MainWindow nullduring development. Here is the best way to get a resource by name:

public override DataTemplate SelectTemplate( object item, DependencyObject container ) {
    var element = container as FrameworkElement;
    if ( element != null ) {
        var template = element.TryFindResource( "Temp1" ) as DataTemplate;
        if ( template != null ) {
            return template;
        }
    }
    return base.SelectTemplate( item, container );
}

, , . DataTemplate , , .

+2

, Application.Current.MainWindow .

0

More articles:


All Articles