ComboBox Binding

[869570967]

Binding both the SelectedItem and SelectionChanged events to the ComboBox at the same time will cause an exception.

[vb2ae]

What type of project is this wpf, Avalonia ui, maui, Xamarin forms, winui3, or uwp. Can you share a sample app that shows this issue?

[869570967]

Avalonia UI                         <ComboBox SelectedItem="{Binding GeneralSet.Language}"                                      &nbsp;ItemsSource="{Binding GeneralSet.Languages}"                                      &nbsp;DisplayMemberBinding="{Binding Name}"                                      &nbsp;cal:Message.Attach="[Event SelectionChanged] = [Action LanguageChangedCmd]"                                      &nbsp;Width="245"                                      &nbsp;HorizontalAlignment="Left"                                      &nbsp;Margin="0,18,0,0"/&gt; 戏子。 ***@***.***

[vb2ae]

I can reproduce. I see I am getting an error. Will work on a fix

As a work around you can use the Set part of your property. Added this to the Avalonia features app MenuViewModel

    public void LanguageChangedCmd()
    {
        DisplayName = SelectedItem?.Title;
    }
    public BindableCollection<FeatureViewModel> Features { get; }
    public FeatureViewModel SelectedItem
    {
        get => _selectedItem;
        set
        {
            if (_selectedItem != value)
            {
                _selectedItem = value;
                NotifyOfPropertyChange(nameof(SelectedItem));
                LanguageChangedCmd();
            }
        }
    }

Xaml MenuView

<StackPanel>
     <ComboBox SelectedItem="{Binding SelectedItem}" ItemsSource="{Binding Features}"
              DisplayMemberBinding="{Binding Title}"
              ></ComboBox>

[869570967]

Okay, please fix it as soon as possible. I am currently using the preview version. You can let me know once it's updated. Thank you.

[869570967]

@vb2ae

I cloned your repository for debugging and found that the exception occurred here. Then I traced it and discovered that the command was triggered before the View was loaded, which caused the issue. So I tried to fix it by adding a line of code where it executes to check if the control is loaded; if it is not loaded, I return. After adding these two lines of code, it ran normally. I created a new branch bug_988, you can test it and see. If this is a way to fix it without affecting your overall functionality, you might consider merging.

[869570967]

@vb2ae Sorry, I just found out that the push failed. You don't have permission; you can either fix it yourself or give me permission to push to a branch.