WPF: Center Child Window

Here’s a method I’ve found for centering a window to either its parent or the main window for the application, in WPF. It’s not too different from how you do it in WinForms.

For the child window, set its WindowStartupLocation to “CenterOwner”. This will cause it to show in the center of the owning Window.

<Window x:Class="WpfApplication1.TestChild"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="TestChild" Height="300" Width="300"
    WindowStartupLocation="CenterOwner">

Now, all that’s left to do is set its owner before displaying it. If the code you’re using to display the window is running inside of a Window class, then you can just use this.

TestChild testWindow = new TestChild();
testWindow.Owner = this;
testWindow.Show();

This isn’t always the case, however; sometimes, you need to display the child window from the code running on a page or a user control. In this case, you want the child window to be centered to the main window of the application.

TestChild testWindow = new TestChild();
testWindow.Owner = Application.Current.MainWindow;
testWindow.Show();