In XAML, What is the correct XML namespace for VisualStateManager?

Question

I'm trying to restyle a few ToggleButtons. Apparently I cannot simply set the background to a new color, because there is a "Control Template" that provides the ToggleButton's visual behavior. So what I need to do is specify in XAML a replacement "ControlTemplate" for the ToggleButton that provides different visual behavior, beyond the simple background color.
Q1. Is this correct?

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I figured to start with the "default" controltemplate for the ToggleButton, which I grabbed from here, and then modify it. Actually that is the default ControlTemplate for Silverlight, I guess, and I am not using Silverlight, I'm using WPF. But... The corresponding doc page for WPF does not include a specification of the default controltemplate. It provides "a" ControlTemplate, which is not what I want.
Q2. I'm not sure if it matters that I am using the thing from Silverlight. Does it?

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In the Silverlight example, there is an XML namespace prefix of of vsm applied to the VisualStateManager. Apparently the xml namespace is

  xmlns:vsm = "clr-namespace:System.Windows;assembly=System.Windows"  

... but somewhere else I read that this XML namespace "is no longer necessary."

This is all very very confusing.

In the Googlespace, there are references to something called "The WPF toolkit" which I have had prior exposure to - I used it for an autocomplete textbox prior to the release of WPF V4. I am guessing that some of the WPF Toolkit stuff was rolled into WPF for .NET v4.0, and that is why I no longer have to specify the WPF toolkit.
Q3. If someone could confirm that understanding I'd appreciate it.

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Ok, now starting with the "default" ControlTemplate for ToggleButton, my first step was to compile it, before making any changes. It does not compile, failing with

c:\dev...\ToggleButtonStyle1.xaml(23,14): error MC3074: The tag 'VisualStateManager.VisualStateGroups' does not exist in XML namespace 'http://schemas.microsoft.com/winfx/2006/xaml/presentation'. Line 23 Position 14.

Clear enough. I then looked at the documentation for specifying VisualStateManager in XAML. It, confusingly enough, specifies two xml namespaces, one of them is the one I actually used.

Q4 Um, which of these am I supposed to use? One of them, I DID use, and it didn't work. The documentation is completely unclear on what it means to specify TWO XML namespaces. (off with their heads!)

I have a reference to PresentationFramework.dll in the project file:

  <ItemGroup>
     ....
    <Reference Include="PresentationFramework" />
  </ItemGroup>

I am not using Visual Studio here; I'm using a text editor. I want to understand how it works, not what buttons to push.

Thanks for any help y'all can provide.

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Just a side comment - this all seems very very complicated. All I want to do is change the color of a ToggleButton when it is ON. It really shouldn't be this complicated.

Answer 1

You don't need to specify a namespace for the VSM (the http://schemas.microsoft.com/winfx/2006/xaml/presentation namespace is the default WPF namespace, declared as xmlns="..." in most standard .xaml's) -- you can however only use it at certain parts of your visual hierarchy.

For example, when I use the VSM in a standard UserControl, it looks something like so:

<UserControl x:Class="Whatever"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Grid x:Name="LayoutRoot">
    <VisualStateManager.VisualStateGroups>
      <VisualStateGroup x:Name="CommonStates">
        <VisualState x:Name="Disabled">
          <!-- Storyboards go here -->
        </VisualState>
      </VisualStateGroup>
    </VisualStateManager.VisualStateGroups>
  </Grid>
</UserControl>

Placing the VSM xaml at this level will enable your storyboards to refer to any elements contained within the Grid. This works the same in a ControlTemplate like you're working with. One thing to note though, is that while in your own UserControls you can name the visual states whatever you like (because you'll ultimately be making calls to switch to that visual state in code), with the built-in controls, your visual states have to be named exactly what the control is expecting.