ResizeGrip style in xaml ignores mouseover trigger

Question

I'm currently using the following xaml to style the resizegrip of a window, but it seems to ignore the ismouseover trigger.

<Style x:Key="{x:Type ResizeGrip}" TargetType="{x:Type ResizeGrip}">
    <Setter Property="MinWidth" Value="{DynamicResource {x:Static SystemParameters.VerticalScrollBarWidthKey}}"/>
    <Setter Property="MinHeight" Value="{DynamicResource {x:Static SystemParameters.HorizontalScrollBarHeightKey}}"/>
    <Setter Property="OverridesDefaultStyle" Value="true" />
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type ResizeGrip}">
                <Grid Name="GripGrid" SnapsToDevicePixels="True" Background="{TemplateBinding Background}">
                    <Path Name="GripPath" Fill="Silver" HorizontalAlignment="Right" Margin="0,0,2,2" VerticalAlignment="Bottom" Data="M 8,0 L 10,0 L 10,2 L 8,2 Z M 4,4 L 6,4 L 6,6 L 4,6 Z M 8,4 L 10,4 L 10,6 L 8,6 Z M 0,8 L 2,8 L 2,10 L 0,10 Z M 4,8 L 6,8 L 6,10 L 4,10 Z M 8,8 L 10,8 L 10,10 L 8,10 Z"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter TargetName="GripPath" Property="Fill" Value="Red"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

i simply want to change colors of the grip on mouseover/down. can anyone help out or at least point me to the correct direction?

thanks!

Answer 1

in case anyone needs something like this, i'm posting what i did (though not exactly what i was hoping for in)

i practically gave up on setting up the ismouseover trigger for the window's resize grip. what i did was to drop a thumb control on my window and setting a custom style like this:

    <Style x:Key="RzGripThumb" TargetType="{x:Type Thumb}">
<Setter Property="SnapsToDevicePixels" Value="true" />
<Setter Property="OverridesDefaultStyle" Value="true" />
<Setter Property="Template">
    <Setter.Value>
        <ControlTemplate TargetType="{x:Type Thumb}">
        <Grid Name="GripGrid" SnapsToDevicePixels="True" Background="Transparent">
            <Path Name="GripPath" Fill="Gray" HorizontalAlignment="Right" Margin="0,0,2,2" VerticalAlignment="Bottom" Data="F1M9,0L11,0 11,2 9,2 9,0z M9,9L11,9 11,11 9,11 9,9z M9,3L11,3 11,5 9,5 9,3z M9,6L11,6 11,8 9,8 9,6z M0,9L2,9 2,11 0,11 0,9z M3,9L5,9 5,11 3,11 3,9z M3,6L5,6 5,8 3,8 3,6z M6,9L8,9 8,11 6,11 6,9z M6,3L8,3 8,5 6,5 6,3z M6,6L8,6 8,8 6,8 6,6z"/>
        </Grid>
        <ControlTemplate.Triggers>
            <Trigger Property="IsMouseOver" Value="true">
                <Setter TargetName="GripPath" Property="Fill" Value="White"/>
            </Trigger>
            <Trigger Property="IsMouseCaptured" Value="true">
                <Setter TargetName="GripPath" Property="Fill" Value="Lime"/>
            </Trigger>
        </ControlTemplate.Triggers>
        </ControlTemplate>
    </Setter.Value>
</Setter>
</Style>

*the ismouseover is to change the color on hover, the ismousecaptured to change it while pressed.

the thumb control should aligned right & bottom.

then i added the DragDelta eventhandler for the thumb containing this:

double xadjust = this.ActualWidth + e.HorizontalChange;
double yadjust = this.ActualHeight + e.VerticalChange;
if ((xadjust >= this.MinWidth) && (yadjust >= this.MinHeight))
{
    this.Width = xadjust; 
    this.Height = yadjust;
}

Answer 2

From the ResizeGrip Class page:

The ResizeGrip is defined as part of the visual tree of a Window.

Therefore, you need to alter the ControlTemplate of the Window to make your changes of the ResizeGrip work. Set your Style as a DynamicResource for the ResizeGrip Style in the Window ControlTemplate.

Here is an example adapted from the Window Styles and Templates page on MSDN:

<Style x:Key="{x:Type Window}"
       TargetType="{x:Type Window}">
  <Setter Property="SnapsToDevicePixels"
          Value="true" />
  <Setter Property="Template">
    <Setter.Value>
      <ControlTemplate TargetType="{x:Type Window}">
        <Grid>
          <Grid.Background>
            <SolidColorBrush Color="{DynamicResource WindowColor}"/>
          </Grid.Background>
          <AdornerDecorator>
            <ContentPresenter />
          </AdornerDecorator>
          <ResizeGrip x:Name="WindowResizeGrip"
                      HorizontalAlignment="Right"
                      VerticalAlignment="Bottom"
                      Visibility="Collapsed"
                      IsTabStop="false" />
                      Style="{DynamicResource YourStyle}"
        </Grid>
        <ControlTemplate.Triggers>
          <Trigger Property="ResizeMode"
                   Value="CanResizeWithGrip">
            <Setter TargetName="WindowResizeGrip"
                    Property="Visibility"
                    Value="Visible" />
          </Trigger>
        </ControlTemplate.Triggers>
      </ControlTemplate>
    </Setter.Value>
  </Setter>
</Style>

You could use a StaticResource if you will not be making any further changes to the Style.