v11.3.7 "[Control] PlatformImpl is null, couldn't handle input."

[torum]

Hi!
This isn't much of an "issue", but after upgrading Avalonia from v11.3.6 to v11.3.7 yesterday, I started getting
[Control] PlatformImpl is null, couldn't handle input. (PopupRoot [some number])
in the debug output window every time I click on a flyout menu.

Everything seems to be working fine except this message showing up. It's not a big deal at all, but I thought I just let you know.

[LemmusLemmus]

I am also experiencing this. It is probably worth creating an issue.

[torum]

Hi! Yes, probably I should have.. or at least I should have left a comment in the release page #19760 in stead of here (I noticed that page after I posted here).
But since we are here, I think I'll wait little while and see what happens. If you think an issue needs to be created, please go ahead and do so. I don't mind at all.

[sageikosa]

Similar issue, but with ComboBox. with the added bitterness that when their are two combo boxes are in the same data template, the second comboBox (in flow order) will not fire changed events for the view model. I worked around it by wrapping my second combobox in a content control and binding to the same model. Still gets the "[Control] PlatformImpl is null, couldn't handle input. (PresentationSource" debug message, but at least I can capture and complete combo box changes on the "2nd" combo box.

  [...]
  <DockPanel>
    <StackPanel Orientation="Horizontal" DockPanel.Dock="Top" Margin="4" Background="AliceBlue">
      <Label Content="Sources" Margin="4"/>
     
     <!-- -----
       this combo box works just fine
     ----- -->
      <ComboBox ItemsSource="{Binding Sources}"
                x:Name="cboSource"
                IsEditable="False"
                MinWidth="240"
                SelectedItem="{Binding SelectedSource}">
        <ComboBox.ItemTemplate>
          <DataTemplate x:DataType="cticifs:SourceDto">
            <TextBlock Text="{Binding SourceKey.KeyVal}"></TextBlock>
          </DataTemplate>
        </ComboBox.ItemTemplate>
      </ComboBox>
    </StackPanel>
	[...]
        <DockPanel>
          <StackPanel Orientation="Horizontal" DockPanel.Dock="Top" HorizontalAlignment="Center">
            <!-- buttons and drop-down for paging -->
            <TextBlock Text="Page" VerticalAlignment="Center"/>
			
			<!-- ----- 
				 without this ContentControl and DataTemplate wrapping, 
			     the combo box will not allow actually changing selection, nor fire changed events 
                             however, if I remove the first combobox, it will work fine without the overwrapping
			----- -->
			
            <ContentControl Content="{Binding}">
              <ContentControl.DataTemplates>
                <DataTemplate DataType="ctxvms:AllSourcesVM">
                  <ComboBox ItemsSource="{Binding Pages}"
                            x:Name="cboPage"
                            MinWidth="100"
                            DisplayMemberBinding="{Binding DataType={x:Type ctxvm:PageNumber}, Path=PageNum}"
                            IsEditable="False"
                            SelectedItem="{Binding CurrentPage}">
                  </ComboBox>
                </DataTemplate>
              </ContentControl.DataTemplates>
            </ContentControl>

[LaurentInSeattle]

Same issue for me, also with ComboBox'es, when selecting an item.

"My" work-around: Schedule a dispatch to the UI thread to do the corresponding action.

partial void OnSelectedIndexChanged(int value) { if (value >= 0 && value < this.SupportedFilters.Count) { // Wait one frame before launching the image color lookup process // If we dont, the app randomly freezes, with no exceptions thrown. // Possible Avalonia Bug ? Need to test with latest 12.0.5 // Debug Output shows: // [Control] PlatformImpl is null, couldn't handle input. (PresentationSource #<some number>>) Schedule.OnUiThread(66, () => { this.selectedFilter = filters[value]; this.UpdateModel(); }, DispatcherPriority.Background); } }

[torum]

FYI, an issue has already created for this a while ago.

#19892

Cheers!

[LaurentInSeattle]

Nope, this something that popped up for ComboBox'es with Avalonia 12.0.4