XamlParseException occurred: Failed to create a 'System.Windows.Style' from the text 'PhoneMasterGridColumnHeader'

Question

I have four datagrids on a Silverlight 4 page. I'm trying to set different column header styles for each grid. I found this XAML which works when I embed it in each DataGrid inside <sdk:DataGrid.ColumnHeaderStyle> tags:

  <Style TargetType="primitives:DataGridColumnHeader" >
    <Setter Property="Template">
      <Setter.Value>
        <ControlTemplate TargetType="primitives:DataGridColumnHeader">
          <Grid Name="Root">
            <vsm:VisualStateManager.VisualStateGroups>
              <vsm:VisualStateGroup x:Name="SortStates" >
                <vsm:VisualStateGroup.Transitions>
                  <vsm:VisualTransition GeneratedDuration="00:00:0.1" />
                </vsm:VisualStateGroup.Transitions>
                <vsm:VisualState x:Name="Unsorted" />
                <vsm:VisualState x:Name="SortAscending">
                  <Storyboard>
                    <DoubleAnimation Storyboard.TargetName="SortIcon" Storyboard.TargetProperty="Opacity" Duration="0" To="1.0" />
                  </Storyboard>
                </vsm:VisualState>
                <vsm:VisualState x:Name="SortDescending">
                  <Storyboard>
                    <DoubleAnimation Storyboard.TargetName="SortIcon" Storyboard.TargetProperty="Opacity" Duration="0" To="1.0" />
                    <DoubleAnimation Storyboard.TargetName="SortIconTransform" Storyboard.TargetProperty="ScaleY" Duration="0" To="-.9" />
                  </Storyboard>
                </vsm:VisualState>
              </vsm:VisualStateGroup>
            </vsm:VisualStateManager.VisualStateGroups>
            <Grid.RowDefinitions>
              <RowDefinition Height="*" />
              <RowDefinition Height="*" />
              <RowDefinition Height="Auto" />
            </Grid.RowDefinitions>
            <Grid.ColumnDefinitions>
              <ColumnDefinition Width="Auto" />
              <ColumnDefinition Width="*" />
              <ColumnDefinition Width="Auto" />
            </Grid.ColumnDefinitions>
            <Rectangle x:Name="BackgroundRectangle" Stretch="Fill" Grid.ColumnSpan="2" Grid.RowSpan="2">
              <Rectangle.Fill>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                  <GradientStop Color="Transparent" Offset="0" />
                  <GradientStop Color="LavenderBlush" Offset="1" />
                </LinearGradientBrush>
              </Rectangle.Fill>
            </Rectangle>
            <ContentPresenter Grid.RowSpan="2" Content="{TemplateBinding Content}" Cursor="{TemplateBinding Cursor}" HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" VerticalAlignment="{TemplateBinding VerticalContentAlignment}" Margin="{TemplateBinding Padding}" />
            <Rectangle Name="VerticalSeparator" Grid.RowSpan="2" Grid.Column="2" Width="1" VerticalAlignment="Stretch" Fill="{TemplateBinding SeparatorBrush}" Visibility="{TemplateBinding SeparatorVisibility}" />
            <Path Grid.RowSpan="2" Name="SortIcon" RenderTransformOrigin=".5,.5" HorizontalAlignment="Left" VerticalAlignment="Center" Opacity="0" Grid.Column="1" Stretch="Uniform" Width="8" Data="F1 M -5.215,6.099L 5.215,6.099L 0,0L -5.215,6.099 Z ">
              <Path.Fill>
                <SolidColorBrush Color="#FF444444" />
              </Path.Fill>
              <Path.RenderTransform>
                <TransformGroup>
                  <ScaleTransform x:Name="SortIconTransform" ScaleX=".9" ScaleY=".9"  />
                </TransformGroup>
              </Path.RenderTransform>
            </Path>
          </Grid>
        </ControlTemplate>
      </Setter.Value>
    </Setter>
  </Style>

When I put it in a separate resource dictionary and remove the aforementioned tags, it also works, applying to all four headers. But when I try to create a specific version of it in the resource dictionary but changing the first line to this:

<Style x:Key="ADGridColumnHeader" TargetType="primitives:DataGridColumnHeader" >

and adding this to the DataGrid:

ColumnHeaderStyle="PhoneMasterGridColumnHeader"

I get the error: XamlParseException occurred: Failed to create a 'System.Windows.Style' from the text 'PhoneMasterGridColumnHeader'. I can't work out what's wrong. I'm still struggling to get to grips with Styles and Resource Dictionaries. Any idea?

Answer 1

Try it like this:-

 ColumnHeaderStyle="{StaticResource PhoneMasterGridColumnHeader}"

The ColumnHeaderStyle property is expecting to receive an object of type Style. Now you could define that value like this:-

 <DataGrid.ColumnHeaderStyle>
    <Style TargetType="primitives:DataGridColumnHeade">
      <!--  You setters here -->
    </Style>
 </DataGrid>

Or you might for some bizare reason have the style exposed as a property called HeaderStyle on a ViewModel which is the current DataContext for the grid:-

 <DataGrid ColumnHeaderStyle="{Binding HeaderStyle}" >

The point is that there are several different ways property values could be acquired in Xaml. Referencing a resource is just one of them. Hence simply stating ColumnHeaderStyle="MyStyle" is at least ambiguous so we need to explict state that we want to acquire the value via static resources.