Button Control In WPF

This tutorial covers how to create a button, add button click event handler, and how to format a button in WPF using C# and XAML.

 

Button control

 

The Button element represents a WPF Button control in XAML at design-time. 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 control. The x:Name attribute represents the name of the control, which is a unique identifier of a control.

 

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

<Button x:Name="DrawCircleButton" Height="80" Width="150" Content="Draw Circle" >

Listing 1

 

Figure 1

As you can see from Figure 1, by default the Button is place in the center of the page. We can place a Button control where we want by using the Margin, VerticalAlignment and HorizontalAlignment attributes that sets the margin, vertical alignment, and horizontal alignment of a control.

 

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="30" Width="100"
   Content="Draw Circle"
   Margin="10,10,0,0" VerticalAlignment="Top"
   HorizontalAlignment="Left">
</Button>

Listing 2

 

Figure 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="Random Number" Click="RandomNumber_Click">
</Button>

The code for the click event handler looks like following.

private void RandomNumber_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 random number the Button click event handler.

public void RandomNumber_Click(object sender, EventArgs e)
{
   Random generator = new Random();
   int randomValue;
   randomValue = generator.Next(1, 10);
   textBlock1.Text += " " + randomValue.ToString();
}

Listing 3

 

Now, let's apply some formatting to oyr control. Here is the final code of Windows.xaml (WPF application window).

<Window x:Class="HelloWPF.Window1"
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   Title="Window1" Height="300" Width="300">
<Grid Background="Azure">
<Button Height="23" Margin="15,15,125,0" Name="RandomNumber" VerticalAlignment="Top" Click="RandomNumber_Click" Background="Blue">Random Number
</Button>
   <ScrollViewer Margin="0,50,0,0">
      <TextBlock Name="textBlock1" TextWrapping="Wrap" FontSize="20" FontWeight="Bold" />
   </ScrollViewer>
</Grid>
</Window>

Code at the button click event hander, that is in Windows.xaml.cs class.

public void RandomNumber_Click(object sender, EventArgs e)
{
   Random generator = new Random();
   int randomValue;
   randomValue = generator.Next(1, 10);
   textBlock1.Text += " " + randomValue.ToString();
}

Now, when you run the application, you will see the following Window and click on the Random Number button will generate a random number and display on the window.

 

Figure 3

 

Formatting a Button

 

Not let's get a little creative. How about we create a Button control with a border formatting, background, and foreground of the Button?

The BorderBrush property of the Button sets a brush to draw the border of a Button. You may use any brush to fill the border.

 

The following code snippet uses a linear gradient brush to draw the border with a combination of red and blue color.

<Button.BorderBrush>
   <LinearGradientBrush StartPoint="0,0" EndPoint="1,1" >
      <GradientStop Color="Blue" Offset="0" />
      <GradientStop Color="Red" Offset="1.0" />
   </LinearGradientBrush>
</Button.BorderBrush>

The Background and Foreground properties of the Button set the background and foreground colors of a Button. You may use any brush to fill the border.

 

The following code snippet uses linear gradient brushes to draw the background and foreground of a Button.

<Button.Background>
   <LinearGradientBrush StartPoint="0,0" EndPoint="1,1" >
      <GradientStop Color="Blue" Offset="0.1" />
      <GradientStop Color="Orange" Offset="0.25" />
      <GradientStop Color="Green" Offset="0.75" />
      <GradientStop Color="Red" Offset="1.0" />
   </LinearGradientBrush>

</Button.Background>
<Button.Foreground>
   <LinearGradientBrush StartPoint="0,0" EndPoint="1,1" >
      <GradientStop Color="Orange" Offset="0.25" />
      <GradientStop Color="Green" Offset="1.0" />
   </LinearGradientBrush>

</Button.Foreground>

Summary

 

In this article, I discussed how we can use a Button control in WPF and C#.