WPF Events in ResourceDictionary for a ControlTemplate

Question

I'm currently trying to implement a Metro styled Window.
So i've made the following styles inside a ResourceDictionary:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

<!-- Brushes -->
<SolidColorBrush x:Key="BackgroundColor" Color="#FFFFFFFF" />

<!-- Buttons -->
<Style x:Key="MetroControlBoxButton" TargetType="Button">
    <Setter Property="Background" Value="{StaticResource BackgroundColor}" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <ContentPresenter />
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

<!-- Windows -->
<Style x:Key="MetroWindow" TargetType="Window">
    <Setter Property="UseLayoutRounding" Value="True" />
    <Setter Property="WindowStyle" Value="None" />
    <Setter Property="ResizeMode" Value="NoResize" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Window">
                <Grid Background="{StaticResource BackgroundColor}">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="6" />
                        <RowDefinition Height="24" />
                        <RowDefinition Height="*" />
                        <RowDefinition Height="24" />
                        <RowDefinition Height="6" />
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="6" />
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="6" />
                    </Grid.ColumnDefinitions>

                    <Rectangle Name="topLeftBorderRectangle" Fill="Red" Grid.Row="0" Grid.Column="0" />
                    <Rectangle Name="topCenterBorderRectangle" Fill="Orange" Grid.Row="0" Grid.Column="1" />
                    <Rectangle Name="topRightBorderRectangle" Fill="Red" Grid.Row="0" Grid.Column="2" />
                    <Rectangle Name="middleLeftBorderRectangle" Fill="Orange" Grid.Row="1" Grid.RowSpan="3" Grid.Column="0" />
                    <Rectangle Name="middleRightBorderRectangle" Fill="Orange" Grid.Row="1" Grid.RowSpan="3" Grid.Column="2" />
                    <Rectangle Name="bottomLeftBorderRectangle" Fill="Red" Grid.Row="4" Grid.Column="0" />
                    <Rectangle Name="bottomCenterBorderRectangle" Fill="Orange" Grid.Row="4" Grid.Column="1" />
                    <Rectangle Name="bottomRightBorderRectangle" Fill="Red" Grid.Row="4" Grid.Column="2" />

                    <Rectangle Name="statusBarRectangle" Fill="Yellow" Grid.Row="3" Grid.Column="1" />

                    <Grid Grid.Row="1" Grid.Column="1">
                        <Grid.RowDefinitions>
                            <RowDefinition Height="*" />
                        </Grid.RowDefinitions>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="Auto" />
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition Width="28" />
                            <ColumnDefinition Width="28" />
                            <ColumnDefinition Width="28" />
                        </Grid.ColumnDefinitions>

                        <Rectangle Name="dragRectangle" Fill="Yellow" Grid.Row="0" Grid.Column="1" />
                        <Button Name="minimizeButton" Content="_" Grid.Row="0" Grid.Column="2" Style="{StaticResource MetroControlBoxButton}" Command="{Binding Path=DataContext.MinimizeCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
                        <Button Name="maximizeButton" Content="[]"  Grid.Row="0" Grid.Column="3" Style="{StaticResource MetroControlBoxButton}" Command="{Binding Path=DataContext.MaximizeNormalizeCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
                        <Button Name="closeButton" Content="X" Grid.Row="0" Grid.Column="4" Style="{StaticResource MetroControlBoxButton}" Command="{Binding Path=DataContext.CloseCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Window}}}" />
                    </Grid>

                    <ContentPresenter Grid.Row="2" Grid.Column="1" />
                </Grid>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

</ResourceDictionary>

My problem is that i have no idea how to implement de drag feature.
My dragRectangle doesn't have a Command property so how can i call DragMove() on MouseLeftButtonDown on a Rectangle using MVVM?

Thanks

Pignut

Answer 1

A ResourceDictionary can have code behind just like Windows etc. so you could add an event handler and call DragMove from there

Setting up the code behind requires a couple of steps.

• If your ResourceDictionary is called MetroStyleResourceDictionary.xaml you add a new file in Visual Studio in the same folder called MetroStyleResourceDictionary.xaml.cs

• The code behind file should then look like this

  public partial class MetroStyleResourceDictionary
  {
      //...
  }
  

• After that you need to add the x:Class attribute to the Xaml file

  <ResourceDictionary x:Class="YourNamespace.MetroStyleResourceDictionary"
                      xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
      <!--...-->
  </ResourceDictionary>
  

Now you can add an event handler to the dragRectangle for MouseLeftButtonDown. You'll also need to get a hold of the Window so binding that to Tag might be a good idea

<Rectangle Name="dragRectangle"
           MouseLeftButtonDown="dragRectangle_MouseLeftButtonDown"
           Tag="{Binding RelativeSource={RelativeSource AncestorType={x:Type Window}}}"
           .../>

And finally you can add the event handler to the code behind file which will look like this

public partial class MetroStyleResourceDictionary
{
    void dragRectangle_MouseLeftButtonDown(object sender, System.Windows.Input.MouseButtonEventArgs e)
    {
        Rectangle dragRectangle = sender as Rectangle;
        Window window = dragRectangle.Tag as Window;
        if (window != null)
        {
            window.DragMove();
        }
    }
}

Cherubini

Thank you from me for explaining exactly how to do this. I have probably read 4 SO "answers" from people who talk down to the questioner for asking the question but who never answer the question fully. – Slow