Question

Does anyone have any pointers for creating a tristate image button?

I have the following but what I really want to do is have a control with multiple ImageSource properties like <Controls.TristateButton Image="" HoverImage="" PressedImage="" />

<Style TargetType="{x:Type Button}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type Button}">
                <StackPanel Orientation="Horizontal" >
                    <Image Name="PART_Image" Source="path to normal image" />
                </StackPanel>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsMouseOver" Value="True">
                        <Setter Property="Source" Value="path to mouse over image" TargetName="PART_Image"/>
                    </Trigger>
                    <Trigger Property="IsPressed" Value="True">
                        <Setter Property="Source" Value="path to pressed image" TargetName="PART_Image"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

Answer 1

The accepted answer to this StackOverflow question shows an easy way to do this:
WPF – How to create image button with template

You create property triggers on the IsEnabled and IsPressed properties and show or hide the images as needed.

As Avanka noted in his answer, you’ll need to create dependency properties to set the paths to the images.