Question

So in my main app ResourceDictionary I have a style that starts with

 <Style TargetType="{x:Type TabItem}" x:Key="{x:Type TabItem}">

Now what I’m doing is overriding the TabControl to make a custom control(without ANY xaml). The problem is at this point it doesn’t inherit the custom TabControl template.

So what I’m wondering, is how can I programatically bind to the ‘x:Key’ of the template, considering it’s bound to a specific control without having my control have a xaml file.

Some places online say to do this

this.Style = (Style)FindResource("TabItem");

But it doesn’t seem to work in my situation. The ‘style’ is in a separate file, and imported into my App.Xaml resource dictionary…so it overrides all TabItems properly, but not the one I overrode.

Here is my App.xaml

<Application x:Class="Octgn.OctgnApp" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

  <Application.Resources>
    <ResourceDictionary>
      <ResourceDictionary.MergedDictionaries>

        <ResourceDictionary Source="/Resources/Themes/Full/ExpressionDark.xaml"/>
       </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
  </Application.Resources>
</Application>

And the item(slightly truncated cause it’s large) from the ExpressionDark.xaml

<Style d:IsControlPart="True" TargetType="{x:Type TabItem}" x:Key="{x:Type TabItem}">
    <Setter Property="Foreground" Value="{DynamicResource TextBrush}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type TabItem}">
                <Grid x:Name="grid" Margin="2,1,2,3">
                    <Grid.LayoutTransform>
                        <TransformGroup>
                            <ScaleTransform ScaleX="1" ScaleY="1"/>
                            <SkewTransform AngleX="0" AngleY="0"/>
                            <RotateTransform Angle="0"/>
                            <TranslateTransform X="0" Y="0"/>
                        </TransformGroup>
                    </Grid.LayoutTransform>
                    <Border x:Name="border" BorderBrush="{x:Null}" CornerRadius="2,2,2,2" Opacity="0.5">
                        <Border.Background>
                            <LinearGradientBrush EndPoint="0.5,0.976" StartPoint="0.5,0.039">
                                <GradientStop Color="#7F595959" Offset="0" />
                                <GradientStop Color="#19FFFFFF" Offset="1" />
                            </LinearGradientBrush>
                        </Border.Background>
                    </Border>
                    <Border x:Name="SelectedBorder" BorderBrush="{x:Null}" CornerRadius="2,2,2,2" Opacity="0" Background="{DynamicResource SelectedBackgroundBrush}"/>
                    <Border x:Name="HoverBorder" BorderBrush="{x:Null}" CornerRadius="2,2,2,2" Opacity="0">
                        <Border.Background>
                            <LinearGradientBrush EndPoint="0.5,0.976" StartPoint="0.5,0.039">
                                <GradientStop Color="#7F595959" Offset="0" />
                                <GradientStop Color="#19FFFFFF" Offset="1" />
                            </LinearGradientBrush>
                        </Border.Background>
                    </Border>
                    <Grid>
                        <ContentPresenter x:Name="ContentSite" RecognizesAccessKey="True" ContentSource="Header" d:LayoutOverrides="Width, Height" HorizontalAlignment="Center" Margin="6,1,6,1" VerticalAlignment="Center" />
                    </Grid>
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

This style auto applies to a TabItem, but I’m trying to apply it to my override of TabItem.

Here’s the code for that

/// <summary>
/// The chat bar item.
/// </summary>
public class ChatBarItem : TabItem
{
    /// <summary>
    /// Sets the Chat Room
    /// </summary>
    private readonly NewChatRoom room;

    /// <summary>
    /// Initializes static members of the <see cref="ChatBarItem"/> class.
    /// </summary>
    static ChatBarItem()
    {
        DefaultStyleKeyProperty.OverrideMetadata(
            typeof(ChatBarItem), new FrameworkPropertyMetadata(typeof(TabItem)));
    }   

    /// <summary>
    /// Initializes a new instance of the <see cref="ChatBarItem"/> class.
    /// </summary>
    /// <param name="chatRoom">
    /// The chat Room.
    /// </param>
    public ChatBarItem(NewChatRoom chatRoom)
    {
        this.room = chatRoom;
        this.ConstructControl();
    }

    /// <summary>
    /// Initializes a new instance of the <see cref="ChatBarItem"/> class.
    /// </summary>
    public ChatBarItem()
    {
        this.room = null;
        this.ConstructControl();
    }

    /// <summary>
    /// Constructs this control
    /// </summary>
    private void ConstructControl()
    {
        //this.Background = Brushes.Transparent;
        //this.BorderThickness = new Thickness(0);
        //this.Style = (Style)FindResource("TabItem");
        // this is where I want to set the style of this control

        // Main content object
        var mainBorder = new Border { Margin = new Thickness(5) };

        // Main content grid
        var g = new Grid();
        g.ColumnDefinitions.Add(new ColumnDefinition());
        g.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(16) });

        // Create item label
        var label = new TextBlock() { VerticalAlignment = VerticalAlignment.Center };
        if (this.IsInDesignMode() || this.room == null)
        {
            label.Inlines.Add(new Run("test"));
        }
        else
        {
            label.Inlines.Add(new Run(this.room.GroupUser.User.User));
        }

        // Create close button
        var borderClose = new Border { Width = 16, Height = 16 };
        var imageClose = new Image()
            {
                Source = new BitmapImage(new Uri("pack://application:,,,/Octgn;component/Resources/close.png")), 
                Stretch = Stretch.Uniform
            };

        // --Add items to items

        // Add close image to closeBorder
        borderClose.Child = imageClose;

        // Add Close 'button' to grid
        g.Children.Add(borderClose);
        Grid.SetColumn(borderClose, 1);

        // Add label to main grid
        g.Children.Add(label);

        // Add main grid to main border
        mainBorder.Child = g;

        // Add main grid to this
        this.Header = mainBorder;
    }
}

If I had a xaml for the TabItem I could easly just go Style=”{DynamicResource {x:Type TabItem}}”(or something similar), but I’m doing it all programatically.

Answer 1

You already tried:

<Style TargetType="{x:Type TabControl}" BasedOn="{StaticResource {x:Type TabControl}}">

</Style>

By the way, you need not define an x:Key, if you want the style to be applied to all TabControl and if you want it to work for your entire application, set the style in App.xaml

---

Edit: I still do not understand exactly what you want to do. (If you can, edit your question again).

But you can try to set the style manually by:

Style customStyle = (Style)Application.Current.FindResource("StyleKey");

As mentioned,

static MyCustomTabControl()
{
     DefaultStyleKeyProperty.OverrideMetadata(typeof(MyCustomTabControl), new FrameworkPropertyMetadata(typeof(TabControl)));
} 

But this will only work if:

1) The style your control is in the file: Themes\Generic.xaml

2) The file “Generic.xaml” has the property “BuildAction” with value = Page.

3) AssemblyInfo.cs contains:

[assembly: ThemeInfo (
     ResourceDictionaryLocation.None,
     ResourceDictionaryLocation.SourceAssembly
)]