How to restyle TextBox of DataGridTextColumn?

Question

I am working with a Wpf application. I have created a custom style for wpf DataGrid (provided in Wpf Toolkit). It all works fine except that I am unable to apply a Style on the TextBox that comes on double clicking the cell(editable mode) in DataGridTextColumn . It display as default style and that doesn't match with my style and looks odd. I have applied a style on the ComboBox in DataGridComboBoxColumn and the CheckBox and all other controls, but this one is not working. Any help plz!!!

Edit:

I have a control library and every control is overridden here for customization (additional functionality) and restyling. These controls are used through out the application. I have to apply this style on the control in control library. So that I can get it reflected in my whole application.

Answer 1

Not perfect, but works...

<Style x:Key="DataGridTextBoxStyle"
    TargetType="TextBox">
    <Setter
        Property="SelectionBrush"
        Value="#FFF8D172" />
    <Setter
        Property="Padding"
        Value="0" />
    <Setter
        Property="VerticalContentAlignment"
        Value="Center" />
    <Setter
        Property="FontSize"
        Value="9pt" />
    <Setter
        Property="SelectionOpacity"
        Value="0.6" />
</Style>

<DataGridTextColumn
   x:Name="TextColumn"
   Header="Header"
   EditingElementStyle="{StaticResource ResourceKey=DataGridTextBoxStyle}"/>

Answer 2

This can also be achieved with the PreparingCellForEdit event of the DataGrid , if you don't want to override the system EditingElementStyle , or if use AutoGenerateColumns , or when you have multiple columns and can't afford to set them individually.

private void DataGrid_PreparingCellForEdit(object sender, 
  DataGridPreparingCellForEditEventArgs e)
{
  if (!(e.Column is DataGridTextColumn && e.EditingElement is TextBox textBox))
    return;

  var style = new Style(typeof(TextBox), textBox.Style);        
  style.Setters.Add(new Setter { Property = ForegroundProperty, Value = Brushes.Red });
  textBox.Style = style;      
}

If you want to apply app resources:

private void DataGrid_PreparingCellForEdit(object sender, 
  DataGridPreparingCellForEditEventArgs e)
{
  if (!(e.Column is DataGridTextColumn && e.EditingElement is TextBox textBox))
    return;

  var tbType = typeof(TextBox);
  var resourcesStyle = Application
    .Current
    .Resources
    .Cast<DictionaryEntry>()
    .Where(de => de.Value is Style && de.Key is Type styleType && styleType == tbType)
    .Select(de => (Style)de.Value)
    .FirstOrDefault();

  var style = new Style(typeof(TextBox), resourcesStyle);
  foreach (var setter in textBox.Style.Setters)
    style.Setters.Add(setter);

  textBox.Style = style;
}