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.

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.