Programmatically changing button icon in WPF

You can accomplish this by changing the content of the button, through an event handler.

You can set both the “Play” Icon and “Stop” Icon as a resource, under Window.Resources like so:

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
<Window.Resources>
    <Image x:Key="Play" Source="/WpfApplication1;component/Play_Icon.png" Height="50" Width="50" />
    <Image x:Key="Stop" Source="/WpfApplication1;component/Stop_Icon.png" Height="50" Width="50"/>
</Window.Resources>
<Grid>
    <Button Click="Button_Click" Name="MediaButton">
        <DynamicResource ResourceKey="Play"/>
    </Button>
</Grid>

Now, when the button is clicked, you can simply change the button’s content to a different resource (the stop icon). In the button’s event handler, you can do this:

C#

private void Button_Click(object sender, RoutedEventArgs e)
{
    if (MediaButton.Content == FindResource("Play"))
    {
        MediaButton.Content = FindResource("Stop");
    }
    else
    {
        MediaButton.Content = FindResource("Play");
    }
}

Edit: Shorter notation

MediaButton.Content = FindResource(MediaButton.Content == FindResource("Play") ? "Stop" : "Play");

Hope this helps, let me know if you have any more questions.