Drag selecting/partially selecting cell content of DataGridTextColumn WPF DataGrid

Question

I have a DataGrid as such:

<DataGrid  
    Name="Employees"  
    AutoGenerateColumns="True"   AutoGeneratingColumn="Employees_AutoGeneratingColumn"  
    EnableColumnVirtualization="True"  
    EnableRowVirtualization="True"  
    IsReadOnly="True"  
    ItemsSource="{Binding EmployeesDataTable}"  
    KeyboardNavigation.TabNavigation="Once"  
    SelectionUnit="CellOrRowHeader"   VirtualizingPanel.VirtualizationMode="Recycling" />  

All the autogenerated columns in the DataGrid are DataGridTextColumns.

I want to be able to select just a part of the cell, not the whole cell (so called drag select).

What is the correct approach to that?

EDIT:

I tried the following approach:

• Setting the IsReadOnly property of the DataGrid to False
• Setting EditingElementStyle of the DataGridTextColumns: <Style TargetType="TextBox">
  <Setter Property="IsReadOnly" Value="True" />
  </Style>

This way, I can select part of the cell content, BUT I have to double-click on it (for it to enter CellEditing mode) and I don't want to do that.

I also tried adding:

<Style.Triggers>
        <Trigger Property="IsSelected" Value="True">
               <Setter Property="Background" Value="{x:Null}" />
               <Setter Property="BorderBrush" Value="{x:Null}" />
        </Trigger>
        <Trigger Property="IsMouseOver" Value="True">
              <Setter Property="IsEditing" Value="True" />
        </Trigger>
 </Style.Triggers>

Which kinda works, but when I move my mouse, the selection is lost, which is pretty annoying.

Answer 1

The DataGridTextColumn is behaving the same whether it is autogenerated or not. You are setting IsReadOnly = True. This may be one of the reasons why it behaves like you described. You could try to delete IsReadOnly="True" or set IsReadOnly="False".

Update:

<DataGrid Name="Employees" Height="200"  
               AutoGenerateColumns="False" IsReadOnly="True"   
               EnableColumnVirtualization="True"   
               EnableRowVirtualization="True"  
               ItemsSource="{Binding EmployeesDataTable}"  
              SelectionUnit="CellOrRowHeader"  
               VirtualizingPanel.VirtualizationMode="Recycling">  
            <DataGrid.Columns>  
                <DataGridTemplateColumn>  
                    <DataGridTemplateColumn.CellTemplate>  
                        <DataTemplate>  
                            <TextBox IsReadOnly="True" Text="{Binding Name}"/>  
                        </DataTemplate>  
                    </DataGridTemplateColumn.CellTemplate>  
                </DataGridTemplateColumn>  
            </DataGrid.Columns>  
        </DataGrid>  

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Answer 2

If the columns are auto-generated, you could handle the AutoGeneratingColumn event and replace the DataGridTextColumns with DataGridTemplateColumns:

private void Employees_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
{
    e.Column = new DataGridTemplateColumn()
    {
        Header = e.Column.Header,
        SortMemberPath = e.PropertyName,
        CellTemplate = XamlReader.Parse("<DataTemplate xmlns=\"http://schemas.microsoft.com/winfx/2006/xaml/presentation\">" +
        "<TextBox Background=\"Transparent\" IsReadOnly=\"True\" TextWrapping=\"Wrap\" BorderThickness=\"0\" " +
        $"Text=\"{{Binding {e.PropertyName}}}\"/>" +
        "</DataTemplate>") as DataTemplate
    };
}