如何从.net类访问UserControl资源

Question

I am trying to access a resource in a UserControl from my TreeViewGroupItemTemplateSelector class. I do not have access to the UserControl class within the TreeViewGroupItemTemplateSelector class. I am having problems formatting the Uri .

PackageExplorer.xaml is the UserControl and resides in the root namespace of the local assembly which also contains the TreeViewGroupItemTemplateSelector class.

I am getting the following error:

Cannot locate resource 'resources/packageexplorer.xaml'

During the instantiation of the Uri.

public class TreeViewGroupItemTemplateSelector : DataTemplateSelector
{
        public override DataTemplate SelectTemplate(object item, DependencyObject container)
        {
            var configGroup = item as IConfigurationGroup;
            if (configGroup == null)
                return null;
            var resourceDictionary = new ResourceDictionary();
            resourceDictionary.Source = new Uri
               ("/myAssembly;component/Resources/myUserControl.xaml",
               UriKind.RelativeOrAbsolute);

            if (configGroup.ItemType == typeof (ReferencePackageConfigurationItem))
                return resourceDictionary["RefreshableHierarchicalDataTemplate"] as DataTemplate;
            else
                return resourceDictionary["DefaultHierarchicalDataTemplate"] as DataTemplate;

        }
    }
}

The XAML (snippet) looks as follows:

<UserControl.Resources>
  <ResourceDictionary>
    <ResourceDictionary.MergedDictionaries>
      <ResourceDictionary>
        <HierarchicalDataTemplate x:Key="DefaultHierarchicalDataTemplate" 
            DataType="{x:Type localconfig:ConfigurationGroup}" 
            ItemsSource="{Binding Path=Items}" 
            ItemTemplateSelector="{StaticResource TreeViewGroupItemTemplateSelector}"/>
        <HierarchicalDataTemplate x:Key="RefreshableHierarchicalDataTemplate" 
            DataType="{x:Type localconfig:ConfigurationGroup}" 
            ItemsSource="{Binding Path=Items}" 
            ItemTemplateSelector="{StaticResource TreeViewGroupItemTemplateSelector}"/>

I've also tried accessing the resource as shown below with the same results:

    resourceDictionary.Source = new 
         Uri("/Resources/myUserControl.xaml", UriKind.RelativeOrAbsolute);

and:

resourceDictionary.Source = new 
     Uri("myUserControl.xaml", UriKind.RelativeOrAbsolute);

Answer 1

it's not clear what you're trying to achieve - but as I understand...

If you're trying to load the entire user-control XAML file - as a resource

User control XAML is not a 'resource dictionary' - I'm not sure as to what error that might produce.

But just separate things . You can use the MergeDictionary to merge any outside 'resource dictionary' XAML into UserControl.Resources - but keep that 'resource' as file on its own - load that, not entire user control, hope that helps