如果我从一个 IsEditable="True" 的 ComboBox 切换到另一个，则 WPF 中 DataGrid 的 SelectedItem 不会触发

Question

In WPF I have a DataGrid . I am using MVVM.

    <DataGrid x:Name="dataGrid" ItemsSource="{Binding DisplayedRows}" 
              SelectedItem="{Binding SelectedRow}" SelectionUnit="FullRow">

If I change row then the setter of the SelectedRow runs as it should.

There is one exception. One of the columns is a DataGridTemplateColumn which contains ComboBox with IsEditable="True"

    <DataTemplate x:Key="CategoryEditingTemplate">
        <ComboBox ItemsSource="{Binding RelativeSource={RelativeSource FindAncestor, 
            AncestorType={x:Type DataGrid}}, Path=DataContext.AppData.CategoryObjects}" 
                  SelectedItem="{Binding Category, ValidatesOnDataErrors=True, UpdateSourceTrigger=LostFocus}" 
                  DisplayMemberPath="FullName" IsEditable="True">
        </ComboBox>
    </DataTemplate>

If I start to edit the content of the ComboBox then I click to another editable ComboBox in another row then the setter of the SelectedRow does not run. I can edit the content of the second ComboBox with keyboard. If I click to another cell in the same row then the system realizes that the row has changed and the setter starts. I want the setter to run as soon as I leave a row.

Update 1

Editing mode of a ComboBox in a DataGrid

Answer 1

The input control ( ComboBox ) steals the focus which prevents the DataGrid control from actually selecting the row.

You could handle the PreviewMouseLeftButtonDown event for the input control to overcome this:

private void OnPreviewMouseLeftButtonDown(object sender, MouseButtonEventArgs e) =>
    dataGrid.SelectedItem = ((ComboBox)sender).DataContext;

XAML:

<DataTemplate x:Key="CategoryEditingTemplate">
    <ComboBox PreviewMouseLeftButtonDown="OnPreviewMouseLeftButtonDown" ItemsSource ...