WPF Child Window

WPF ChildWindow Control

A ChildWindow control is a light weight Window that can be used as a child window or a popup control. The parent window is automatically disabled when a child window is active and modal. You can think of a ChildWindow as a custom modal or modeless dialog where you can place any child controls you want. However, the ChildWindow has several common Window properties.

This article demonstrates how to use the ChildWindow control in a WPF application using C# and XAML.  

Adding Reference to WPF Toolkit Extended Assembly

The ChildWindow control is an extension to the WPF Toolkit and does not come with Visual Studio 2010. To use the ChildWindow control in your application, you must add reference to the WPFToolkit.Extended.dll assembly. You can download Extended WPF Tookit from the CodePlex or you can use the WPFToolkit.Extended.dll available with this download. All you need is the DLL. See Downloads section of this article. 

After downloading the WPFToolkit.Extended.dll, you can add reference to your project by right clicking on the project name in Visual Studio, select Add Reference and browse the DLL.  See Figure 1. 


Figure 1

Once the assembly reference is added, the next step is to import the namespace in XAML using the xmlns. As soon as you type xmlns in XAML you should see the http://schemas.microsoft.com/winfx/2006/xaml/presentation/toolkit/extended option in the list. See Figure 2. If you do not see this URL, please read the next section.



Figure 2

Unblocking the WPF Toolkit Assembly

If an assembly reference is not added to your project correctly, you will see the following message when you build your application. 

Unable to load the metadata for assembly 'WPFToolkit.Extended' 

You get this message when try to add reference to the Extended WPF Toolkit to a project and build the project.  The problem here is when you download an assembly from a Website, it is block by default. All you need to do is, unblock the assembly. 

Right click on the DLL and click Unblock button. See Figure 3.   


Figure 3

Remove and add reference again. You are all set.


Creating a ChildWindow

The ChildWindow element represents a WPF ChildWindow control in XAML. The ChildWindow control is defined in the System.Windows.Controls namespace. 

Listing 1 creates a simple ChildWindow control with its Width, Height, Name, IsModal and Caption property. 

<wpfx:ChildWindow Name="PopupChildWindow" Caption="Child Window" Width="300" Height="200" IsModal="True" />

Listing 1

By default, the ChildWindow is not visible. We need to call the Show() method to make a Child Window visible. 


The default output of Listing 1 generates Figure 4. 


Figure 4

Customizing Caption

The Caption property represents the title/caption of the window. Here is the good part. The Caption property can have any element inside it. For example, you can create a child window with caption having an image, text, and shapes.

The code snippet in Listing 2 customizes the title and adds an image and a few shapes to the title and generates Figure 5.

<wpfx:ChildWindow Name="PopupChildWindow" Width="420" Height="200" IsModal="True" Margin="41,37,0,0">
    <wpfx:ChildWindow.Caption >
        <WrapPanel Orientation="Horizontal" Background="Gray" Height="61" Width="407">
            <Ellipse Width="40" Height="40" Fill="Yellow" />     
            <Ellipse Width="20" Height="20" Fill="Blue" />
            <TextBlock Text="Window Title" FontSize="25" Foreground="Green"></TextBlock>
<Image Height="58" HorizontalAlignment="Left" Name="image1" Stretch="Fill" VerticalAlignment="Top" Width="98" Source="/ChildWindowSample;component/Images/mahatma-gandhi1.jpg" />




Listing 2


Figure 5



In this article, we discussed how to use the ChildWindow control in a WPF application using C# and XAML.