Setting an Elements.Resource Style using BasedOn within a Resource Dictionary - wpf

Question

I have a Resource Dictionary that I am using to define the look-and-feel (style) for my application.
I have just created another Resource Dictionary that contains DataTemplates that I am using on several different screens (and even multiple times within the same screen) to display my business objects.
I would like to change some of the default styles within my DataTemplates so that the controls fit better; however I would like the controls to inherit the same style as the rest of the screen. So, naturally I want to use the BasedOn property for this task.
The problem that I am having is that I'm not sure what to set the BasedOn property to.
For example, in the resource dictionary that contains my styles (called "myStyle.xaml") I have:
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:primatives="clr-namespace:System.Windows.Controls.Primitives;assembly=PresentationFramework"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Style TargetType="{x:Type Label}">
<Setter Property="Foreground" Value="#F5F5F5" />
<Setter Property="FontSize" Value="12"></Setter>
<Setter Property="Width" Value="120"></Setter>
<Setter Property="FontFamily" Value="Arial"></Setter>
</Style>
<Style TargetType="{x:Type TextBox}">
<Setter Property="FontSize" Value="12"></Setter>
<Setter Property="Width" Value="120"></Setter>
<Setter Property="Height" Value="25"></Setter>
<Setter Property="Background" Value="Black"></Setter>
</Style>
<!-- .... and so on .... -->
</ResourceDictionary>
I am using this resource in the following window:
<Window x:Class="SiteSetupWindow4"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:primatives="clr-namespace:System.Windows.Controls.Primitives;assembly=PresentationFramework"
Title="A Screen">
<Window.Resources>
<ResourceDictionary x:Key="defaultStyleX">
<ResourceDictionary.MergedDictionaries>
<ResourceDictionary x:Name="DefaultStyles" Source="Resources/myStyle.xaml" />
<ResourceDictionary x:Name="Templates" Source="Resources/myTemplates.xaml"></ResourceDictionary>
</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>
</Window.Resources>
Now, I have another Resource Dictionary that contains DataTemplates that I am using within my window. It is called "myTemplates". The style is applied to the DataTemplate as expected; however, I would like to overwrite some aspects of the style within the DataTemplate (Like width for example).
This is what I have tired, however I cannot get the BasedOn property to work...
(myTemplate.xaml)
<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<DataTemplate x:Key="PanelInfo">
<StackPanel>
<StackPanel.Resources>
<Style TargetType="TextBox" BasedOn="{StaticResource {x:Type TextBox}}">
<Setter Property="Width" Value="120" />
</Style>
<Style TargetType="Label">
<Setter Property="Width" Value="180" />
</Style>
<Style TargetType="ComboBox">
<Setter Property="Width" Value="120" />
</Style>
<StackPanel.Resources>
<StackPanel Orientation="Horizontal">
<Label Content="Type:"></Label>
<ComboBox>
<ComboBoxItem Content="{Binding Path=Type}" IsSelected="True"></ComboBoxItem>
</ComboBox>
<!--...and so on -->
</StackPanel>
</StackPanel>
</ResourceDictionary>
This fails....I have also tried using DynamicResource, but this also fails.
I'm not sure how to get around this.
Any advise would be greatly appreciated!
Thanks,
-Frinny

Answer 1

I was having the same problem with an extended Button Style.
The ResourceKey= is what solved it for me.
This worked:
<Style x:Name="ButtonVisibility"
TargetType="{x:Type Button}"
BasedOn="{StaticResource ResourceKey={x:Type Button}}">

Answer 2

The way you have BasedOn for a type is correct. This will work in theory as long as, at run time, the style that you are basing it on is merged into the tree correctly. Make sure you have the "myStyles.xaml" merged in correctly. You can check this by removing your style you tried to modify and make sure it displays correctly from your style in "myStyles.xaml."
If it isn't there are a lot of places you can go wrong, but it always helps to try merging the styles in the file you are working on, then work up the tree to see where it's missing.
This utility will help you look at what is happing in the tree at run time.
http://blois.us/Snoop/