xaml: How to change basic element properties using custom control through routed events

Question

I have created a custom control button in Generic.xaml file and created a click routed event in CustomControl.cs [C# file for custom control button],When I am defining a click events in MainWidow.cs [C# file for implementing the custom library] file so that its background property will change on button click.

Problem i am facing is that "On Button click" its background property should change but it is not.

MainWindow.xaml

<Window x:Class="my_ToolBox.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:ravi="clr-namespace:my_ToolBox"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <ravi:Button_Primary Text="Primary" x:Name="Primary_button"></ravi:Button_Primary>
</Grid></Window>

MainWindow.cs

namespace my_ToolBox
{

public partial class MainWindow : Window
{

    public MainWindow()
    {
        InitializeComponent();
        Primary_button.onclick+=Primary_button_onclick;  
    }



    private static void Primary_button_onclick(object sender, RoutedEventArgs e)
    {
        MessageBox.Show("Hello robins");
        Button_Primary btn = new Button_Primary();
        btn.Background = new SolidColorBrush(Color.fromRgb(0,0,0));

    }
} 
}

Generic.xaml

<Style TargetType="{x:Type local:Button_Primary}">
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type local:Button_Primary}">
                <Border Background="{TemplateBinding Background}"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        >
                    <Button Height="38" Width="86" Background="#428bca" BorderBrush="#428bca" BorderThickness="0"  Content="{TemplateBinding Text}" FontSize="14" Foreground="white" FontFamily="Segoe UI" x:Name="Primary_button">
                    </Button>
                </Border>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

CustomControl.cs

namespace my_ToolBox
{

public class Button_Primary : Control
{
    private Button clickbutton;

    public static readonly RoutedEvent onclickevent = EventManager.RegisterRoutedEvent("onclick", RoutingStrategy.Direct, typeof(RoutedEventHandler), typeof(Button_Primary));

    static Button_Primary()
    {
        DefaultStyleKeyProperty.OverrideMetadata(typeof(Button_Primary), new FrameworkPropertyMetadata(typeof(Button_Primary)));
    }


    public override void OnApplyTemplate()
    {
        base.OnApplyTemplate();
        clickbutton = GetTemplateChild("Primary_button") as Button;
        if(clickbutton!=null) clickbutton.Click+=clickbutton_Click;

    }

    public event RoutedEventHandler onclick
    {
        add
        {
            AddHandler(onclickevent, value);
        }
        remove
        {
            RemoveHandler(onclickevent, value);
        }
    }



    private void clickbutton_Click(object sender, RoutedEventArgs e)
    {
        RaiseEvent(new RoutedEventArgs(onclickevent));
    }

}
}

Answer 1

Ah, I found your problem... I'm sorry, but it's a real basic one too:

private static void Primary_button_onclick(object sender, RoutedEventArgs e)
{
    MessageBox.Show("Hello robins");
    Button_Primary btn = new Button_Primary();
    btn.Background = new SolidColorBrush(Color.fromRgb(0,0,0));
}

Here, you create a new Button_Primary object and set its Background property and not the Background of your UI element:

Button_Primary btn = new Button_Primary();
btn.Background = new SolidColorBrush(Color.fromRgb(0,0,0));

All you need to do is to access your actual Button_Primary object from the UI... how do you do that? Well, you can find the full story from the How to: Find ControlTemplate-Generated Elements page on MSDN, but the gist of it is this: You need an instance of a control that has the relevant ControlTemplate applied to it and then you can simply use the FrameworkTemplate.FindName Method to access the Button.