Using variable XPaths in Style declarations   

Hello,

I have this simple piece of XAML (just paste it into XAMLPad and it
will work).


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

   <Canvas.Resources>

      <XmlDataProvider x:Key="DataProvider" XPath="Data">
         <x:XData>
            <Data xmlns="">
               <TB Name="TXT_1">
                  <Background>yellow</Background>
               </TB>
               <TB Name="TXT_2">
                  <Background>green</Background>
               </TB>
            </Data>
         </x:XData>
      </XmlDataProvider>

   </Canvas.Resources>

   <Canvas.DataContext>
      <Binding Source="{StaticResource DataProvider}" />
   </Canvas.DataContext>

   <TextBox x:Name="TXT_1" Canvas.Top="0" Height="20" Width="200">
        <TextBox.Background>
          <Binding XPath="TB[@Name='TXT_1']/Background" />
        </TextBox.Background>
   </TextBox>

   <TextBox x:Name="TXT_2" Canvas.Top="40" Height="20" Width="200">
        <TextBox.Background>
          <Binding XPath="TB[@Name='TXT_2']/Background" />
        </TextBox.Background>
   </TextBox>

</Canvas>


Now I looked at how my TextBoxes are declared and I thought to myself:
Well, any TextBox has the same bindings except from the XPath which is
the same apart from the name of the piece of the Xml that I actually
want to be my data source. But on the other hand the value of the
"variable part" in the XPath is always the name of my TextBox.
So I wondered whether I can make all the bindings be part of a style
for TextBoxes. This is what I tried:


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

   <Canvas.Resources>

      <XmlDataProvider x:Key="DataProvider" XPath="Data">
         <x:XData>
            <Data xmlns="">
               <TB Name="TXT_1">
                  <Background>yellow</Background>
               </TB>
            </Data>
         </x:XData>
      </XmlDataProvider>

      <Style x:Key="txtStyle" TargetType="{x:Type TextBox}">
         <Setter Property="TextBox.Background">
            <Setter.Value>
               <SolidColorBrush Color="{Binding XPath=//TB[@Name\=
\'TXT_1\']/Background}" />
            </Setter.Value>
         </Setter>
      </Style>

   </Canvas.Resources>

   <Canvas.DataContext>
      <Binding Source="{StaticResource DataProvider}" />
   </Canvas.DataContext>

   <TextBox x:Name="TXT_1" Canvas.Top="0" Height="20" Width="200"
Style="{StaticResource txtStyle}" />

   <TextBox x:Name="TXT_2" Canvas.Top="40" Height="20" Width="200"
Style="{StaticResource txtStyle}" />

</Canvas>


Works fine, only that I now have a fixed name in the Binding statement
for the Background property. I do not know how to make this variable.
What I would like to have is something like

	<SolidColorBrush Color="{Binding XPath=//TB[@Name\={TemplateBinding
Name}]/Background}" />

Sorry for mixing templates in here, but I thought this would be the
best way to describe what I would like to achieve.

Any suggestions are highly welcome.

Thanks,
Michael

date: Thu, 25 Oct 2007 05:48:28 -0700   author:   unknown