Question

Ok, here’s my simple scenario. I’ve got collection of strings that I’m binding to a TabControl as a proof of concept. As I add strings I want a new tab with the region name as the header and a ItemsControl in the Tab container. That ItemsControl should define a new region.

        <TabControl  x:Name="tabDemo" ItemsSource="{Binding DynamicRegions}" >
        <TabControl.ItemTemplate>
            <DataTemplate>
                <TextBlock Text="{Binding}" />
            </DataTemplate>
        </TabControl.ItemTemplate>
        <TabControl.ContentTemplate>
            <DataTemplate>
                <ItemsControl cal:RegionManager.RegionName="{Binding}" ItemsSource="{x:Null}">

                </ItemsControl>
            </DataTemplate>
        </TabControl.ContentTemplate>
    </TabControl>

From there I add strings to the collection. The tabs show up fine, but when I try to call

   private void AddDynamicRegion(object arg)
  {
     var newRegionName = "Region" + (DynamicRegions.Count + 1).ToString();
     DynamicRegions.Add(newRegionName);
  }

  private void AddRandomRegionContent(object arg)
  {
     if (string.IsNullOrEmpty(SelectedRegion) )
        return; 

     Debug.WriteLine("Injected "  + RegionContent + " into " + SelectedRegion);

     var newContent = new TextBlock() { Text = RegionContent };
     _regionManager.RegisterViewWithRegion(SelectedRegion,() => newContent );

     _regionManager.Regions[SelectedRegion].Activate(newContent);
  }

It either throws an exception that the region doesn’t exist or an exception that creating the region failed and my ItemsControl.ItemsSource is already set. I didn’t really expect this to work out of the box, but is there any way I can create dynamic regions and inject into them at run time?

Update: Calling RegisterViewWithRegion actually injects my textblock…but getting some weird behavior between tabs.

I changed it so I can choose the region and text I want to inject. It always works for the first region I create, but after that, flipping between tabs just shows the stuff I’ve added to the first region. Is the tab control re-using my datatemplate across multiple tabs? I’ve included all my code from the ViewModel. DynamicRegions is just an ObservableCollection

Answer 1

Ok, I’ve got something that works, but I’d like to see what Anderson Imes comes up with.

Basically, I set all the region stuff in code when my tabItems are generated using databinding.

  private void AddDynamicRegion(object arg)
  {
     var newRegionName = "Region" + (DynamicRegions.Count + 1).ToString();
     DynamicRegions.Add(newRegionName);

     var tabItem = View.tabDemo.ItemContainerGenerator.ContainerFromIndex(DynamicRegions.Count - 1) as TabItem;
     var newRegionContainer = new ItemsControl();
     RegionManager.SetRegionName(newRegionContainer,newRegionName);
     RegionManager.SetRegionManager(newRegionContainer, _regionManager);
     tabItem.Content = newRegionContainer;


  }

So then in insert I can just do this, and everything shows up under the correct region. I wonder if there is a better way to do it though.

  private void AddRandomRegionContent(object arg)
  {

     if (string.IsNullOrEmpty(SelectedRegion) )
        return; 

     Debug.WriteLine("Injected "  + RegionContent + " into " + SelectedRegion);

     var newContent = new TextBlock() { Text = RegionContent };
     var region = _regionManager.Regions[SelectedRegion];
     if (region == null)
     {
        Debug.WriteLine("Couldn't find region");
        return;
     }

     region.Add(newContent);
     region.Activate(newContent);

  }