WPF View Styles Referenced By SystemResourceKey

Question

I'm trying to replicate the Style of DataGridComboBoxColumn's TextBlockComboBox. This is the control used by the DataGridComboBoxColumn when the column's cells are not being edited. I was able to find out about this control by viewing the source at referencesource.microsoft.com (I would attempt to link directly to the type in question, but the browser on my work laptop has a security plugin that mangles URLs). Here is a snippet from that source:

    internal class TextBlockComboBox : ComboBox
    {
        static TextBlockComboBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(TextBlockComboBox), new FrameworkPropertyMetadata(DataGridComboBoxColumn.TextBlockComboBoxStyleKey));
            KeyboardNavigation.IsTabStopProperty.OverrideMetadata(typeof(TextBlockComboBox), new FrameworkPropertyMetadata(false));
        }
    }

    /// <summary>
    ///     Style key for TextBlockComboBox
    /// </summary>
    public static ComponentResourceKey TextBlockComboBoxStyleKey
    {
        get
        {
            return SystemResourceKey.DataGridComboBoxColumnTextBlockComboBoxStyleKey;
        }
    }

From this snippet, you can see that the Style for this control has it's key defined in SystemResourceKey.DataGridComboBoxColumnTextBlockComboBoxStyleKey. I would like to copy this Style in order to make additions and modifications in my own codebase. I can't seem to find the Style that this key referes to, however. I tried duplicating the control (since it is an internal type) and using the Visual Studio Designer's Edit Template feature to get a generated copy of the Style/Template, but all I got was the default ComboBox Template. From there, I tried simply using this default ComboBox Style and trying to modify it until it resembled the Style of the TextBlockComboBox, but that's just causing problems.

Does anybody know how to determine what is defined in the Style for the key SystemResourceKey.DataGridComboBoxColumnTextBlockComboBoxStyleKey?

Answer 1

Here is how it's defined in PresentationFramework.Aero2.dll on Windows 8 and later:

<Style x:Key="{x:Static DataGridComboBoxColumn.TextBlockComboBoxStyleKey}" TargetType="{x:Type ComboBox}">
    <Setter Property="Control.Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ComboBox}">
                <ContentPresenter Margin="1,1,1,1" Content="{TemplateBinding ComboBox.SelectionBoxItem}"
                            ContentTemplate="{TemplateBinding ComboBox.SelectionBoxItemTemplate}"
                            ContentTemplateSelector="{TemplateBinding ItemsControl.ItemTemplateSelector}"
                            ContentStringFormat="{TemplateBinding ComboBox.SelectionBoxItemStringFormat}"
                            VerticalAlignment="{TemplateBinding Control.VerticalContentAlignment}"
                            HorizontalAlignment="{TemplateBinding Control.HorizontalContentAlignment}"
                            SnapsToDevicePixels="{TemplateBinding UIElement.SnapsToDevicePixels}" IsHitTestVisible="false"/>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>