Working with Button Control in WPF

Introduction

 

This article demonstrates how to create and use a Button control in WPF using XAML and C#. This article starts with introduction of the Button tag in XAML. After that, it demonstrates how to position and add click event handler of a button. In the end, the article discusses how to create a button at run-time. 

 

Creating a Button

 

The Button XAML element represents a WPF Button control. 

 

<Button/>

 

The Width and Height attributes of the Button element represent the width and the height of a Button. The Content property of the Button element sets the text of a button. The x:Name attribute represents the name of the control, which is a unique identifier of a control. You may also use the Name property to set the name of a control. 

 

The code snippet in Listing 1 creates a Button control and sets the name, height, width, and content of a Button control. 

<Button x:Name="DrawCircleButton" Height="40" Width="120" Content="Draw Circle" >
</Button>

Listing 1

 

The default property of a button is Content. The following code snippet creates the same button as created by Listing 1.

<Button x:Name="DrawCircleButton" Height="40" Width="120" >
                 Draw Circle
</Button>

The output looks like Figure 1. 

 

Figure 1

Positioning a Button

 

If you place a button on a Grid control, the button will be placed in the center of Grid. If you are using a Canvas as your parent control of Button, the Button will be placed in the left top corner of Canvas. 

 

You can use Margin property to position a button control. If you are using a Canvas, you may also use Canvas.Left and Canvas.Top properties.

 

You may also use VerticalAlignment and HorizontalAlignment attributes to set vertical alignment, and horizontal alignment of a button. 

The code snippet in Listing 2 sets the position of the Button control in the left top corner of the page. 

<Button x:Name="DrawCircleButton" Height="40" Width="120"
        Canvas.Left="10" Canvas.Top="10"
        Content="Draw Circle"
        VerticalAlignment="Top"
        HorizontalAlignment="Left">
</Button>

Listing 2

 

Adding a Button Click Event Handler

 

The Click attribute of the Button element adds the click event handler. The following code adds the click event handler for a Button. 

<Button x:Name="DrawCircleButton" Height="40" Width="120"
        Canvas.Left="10" Canvas.Top="10"
        Content="Draw Circle"
        VerticalAlignment="Top"
        HorizontalAlignment="Left">
Click="DrawCircleButton_Click"
</Button>

The code for the click event handler looks like following. 

private void DrawCircleButton_Click(object sender, RoutedEventArgs e)
{

}

Now, whatever code you write in the click event handler that will be executed on the Button click. The code listed in Listing 3 creates a circle on the Button click event handler.

private void DrawCircleButton_Click(object sender, RoutedEventArgs e)
{
    // creates a Circle
    Ellipse circle = new Ellipse();
    circle.Width = 200;
    circle.Height = 200;
    circle.Fill = new SolidColorBrush(Colors.Yellow);
    circle.Stroke = new SolidColorBrush(Colors.Black);
    circle.StrokeThickness = 4;

    LayoutRoot.Children.Add(circle);
}

Listing 3

 

Creating a Button Dynamically

 

The code listed in Listing 5 creates a Button control programmatically. First, it creates a Button object and sets its width, height, contents, background and foreground and later the Button is added to the LayoutRoot. 

private void CreateAButton()
{
    Button btn = new Button();
    btn.Height = 80;
    btn.Width = 150;
    btn.Content = "Click ME";
    btn.Background = new SolidColorBrush(Colors.Orange);
    btn.Foreground = new SolidColorBrush(Colors.Black);
    LayoutRoot.Children.Add(btn);
}

Listing 5

 

Summary

 

In this article, I discussed how we can create a Button control in WPF and C#.  We also saw how we can format a Button by setting its border, background, and foreground properties. After that, we saw you to set an image as the background of a Button. In the end of this article, we saw how to create a Button dynamically.