Question

I’m getting exception:

‘{0}’ is not a Visual or Visual3D.

The only question I found that similar: WPF: System.ArgumentException => {"'{0}' is not a Visual or Visual3D."}

I’m just building “pretty” grid. No need to handle double-clicks. It’s just side-effect when user double-clicks by mistake – this exception throws.

XAML looks like this:

<DataGrid
  ItemsSource="{Binding Source={StaticResource TrucksSource}}"
  CanUserReorderColumns="False" 
  CanUserResizeColumns="True" 
  CanUserResizeRows="False" 
  AutoGenerateColumns="False" 
  BorderThickness="0" 
  CanUserAddRows="False" 
  RowBackground="{StaticResource GrayBackgroundGradientBrush}"
  RowHeight="20" Focusable="False" RowHeaderWidth="0">
  <DataGrid.Columns>
      <DataGridTemplateColumn Header="Select" Width="40" CanUserSort="True" SortMemberPath="IsSelected">
          <DataGridTemplateColumn.CellTemplate>
              <DataTemplate>
                  <CheckBox
                      IsChecked="{Binding IsSelected, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
                      HorizontalAlignment="Center"
                      VerticalAlignment="Center" />
              </DataTemplate>
          </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>
      <DataGridTemplateColumn Header="Team" Width="42" CanUserSort="True" SortMemberPath="TeamDispatcherCaptionShort">
          <DataGridTemplateColumn.CellTemplate>
              <DataTemplate>
                  <Border
                  Margin="-2,-1">
                      <TextBlock ToolTip="{Binding TeamDispatcherCaptionLong}" 
                      Foreground="#414141" FontFamily="Arial" FontSize="12"
                      Text="{Binding TeamDispatcherCaptionShort}" 
                      HorizontalAlignment="Center" VerticalAlignment="Center" />
                  </Border>
              </DataTemplate>
          </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>

I get exception whenever user double-clicks. First column is checkbox. When it’s single-click-ed it works correct. When I click in any area around checkbox – exception.

How do I fix it? There is no code behind, it’s MVVM project

EDIT:

Ok, I went ahead and tried to repro this on small project. I already figured issue but want to know your take on this.. And I need to award this bounty 🙂

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <ResourceDictionary>
            <CollectionViewSource x:Key="WidgetsSource" Source="{Binding Widgets}" />
        </ResourceDictionary>
    </Window.Resources>
    <Grid>
        <DataGrid
            ItemsSource="{Binding Source={StaticResource WidgetsSource}}"
            CanUserReorderColumns="False" 
            CanUserResizeColumns="True" 
            CanUserResizeRows="False" 
            AutoGenerateColumns="False" 
            BorderThickness="0" 
            CanUserAddRows="False" 
            VerticalGridLinesBrush="#00000000" 
            HorizontalGridLinesBrush="Gray" 
            RowBackground="LightGray"
            RowHeight="20" Focusable="False" RowHeaderWidth="0" SelectionUnit="Cell">
            <DataGrid.Columns>
                <DataGridTemplateColumn Header="Prop1" Width="50" CanUserSort="True" SortMemberPath="Prop1">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Border>
                                <TextBlock>
                                    <Run Text="{Binding NestWidg.Prop1}" />
                                </TextBlock>
                            </Border>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
                <DataGridTemplateColumn Header="Prop2" Width="50" CanUserSort="True" SortMemberPath="Prop1">
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <Border>
                                <TextBlock Text="{Binding Prop1}" />
                            </Border>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>                
            </DataGrid.Columns>
        </DataGrid>
    </Grid>
</Window>

VM:

namespace WpfApplication1
{
    using System.Collections.ObjectModel;

    public class MainWindowVM
    {
        public ObservableCollection<Widget> Widgets { get; set; }

        public MainWindowVM()
        {
            this.Widgets = new ObservableCollection<Widget>();

            this.Widgets.Clear();
            this.Widgets.Add(new Widget("a", "b") { NestWidg = new NestWidget { Prop1 = "Nest" } });
        }
    }

    public class Widget
    {
        public Widget(string p1, string p2)
        {
            Prop1 = p1;
            Prop2 = p2;
        }

        public string Prop1 { get; private set; }

        public string Prop2 { get; private set; }

        public NestWidget NestWidg { get; set; }
    }

    public class NestWidget
    {
        public string Prop1 { get; set; }
    }
}

Code behind:

namespace WpfApplication1
{
    using System.Windows;

    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            this.InitializeComponent();
            this.DataContext = new MainWindowVM();
        }
    }
}

Answer 1

Yes. Your sample project throws error now. That’s because you’ve binding with Run. In your first post, you were missing it, so that’s why I couldn’t reproduce it.

It really seems that it’s quite old bug and many users have had it. Knowing microsoft, it wont be fixed anytime soon. (The bug has been part of WPF since beginning I guess).
Your best bet is to be clever.

Bind only objects that are Visuals. < Run > is not Visual.

Youll have to make custom TextBlock that will generate correct Runs based on the DataContext without using binding. You need to declare new depedency property which will be part of TextBlock and hook yourself into UIPropertyChanged method, there you will generate Runs().