GoToState not working on controltemplated usercontrol based on combobox - silverlight

Question

I'm trying to create a custom combobox that shows a loading animation when a bool property is set on it (e.g. IsLoading).
I've created a control template in Blend based on the combobox, and added a textblock inside the togglebutton template. In the code behind I'm calling VisualStateManager.GoToState but it always returns false. I was trying to move to a custom state initially, but I can't even move to states such as Disabled or MouseOver.
I have a usercontrol that just contains a combobox and the style is set to my combobox style containing the control template. I presume GoToState fails because the state is not on the control itself, but inside the combobox. How can I access this?
I'm at a loss as to how to debug this as there are no errors.
thanks

Answer 1

I had a similar problem! I had the Visual States defined within a grid in the ControlTemplate.
<Style x:Key="Image3TextRowButtonStyle" TargetType="Button">
<Setter Property="Foreground" Value="{StaticResource ForegroundBrush}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="Button">
<Grid x:Name="RootGrid" Background="{StaticResource BackgroundBrush}">
...
<VisualStateManager.VisualStateGroups>
...
<VisualStateGroup x:Name="ActiveStates">
<VisualState x:Name="Active">
<Storyboard>
<ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(Panel.Background)" Storyboard.TargetName="RootGrid">
<DiscreteObjectKeyFrame KeyTime="0" Value="{StaticResource BackgroundActiveBrush}"/>
</ObjectAnimationUsingKeyFrames>
</Storyboard>
</VisualState>
<VisualState x:Name="NotActive" />
</VisualStateGroup>
</VisualStateManager.VisualStateGroups>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
And the user control:
<UserControl x:Class="Griesser.Presentation.ContactCenterClient.Client.Control.Image3TextRowButtonUC"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d"
x:Name="Image3TextRowButton">
<Grid>
<Button x:Name="btn" Command="{Binding Command, ElementName=Image3TextRowButton}" Style="{StaticResource Image3TextRowButtonStyle}" />
</Grid>
In the code behind I am looking first for the RootGrid and then use GoToElementState:
private void ChangeVisualActiveState(bool useTransitions)
{
// Search RootGrid, because the Visual States are defined in the ControlTemplate!
FrameworkElement dt = btn.Template.FindName("RootGrid", btn) as FrameworkElement;
if (IsActive)
{
VisualStateManager.GoToElementState(dt, "Active", useTransitions);
}
else
{
VisualStateManager.GoToElementState(dt, "NotActive", useTransitions);
}
}