How do you center your main window in WPF?

Question

I have a WPF application and I need to know how to center the wain window programatically (not in XAML).

I need to be able to do this both at startup and in response

Answer 1

Rect workArea = System.Windows.SystemParameters.WorkArea;
this.Left = (workArea.Width - this.Width) / 2 + workArea.Left;
this.Top = (workArea.Height - this.Height) / 2 + workArea.Top;

This takes into account the taskbar size (by using System.Windows.SystemParameters.WorkArea) and position (by adding workArea.Left and workArea.Top)

Answer 2

Go to property window of MainWindow.xaml

• find WindowStartupLocation property from Common category
• select CenterScreen option from dropdown
• Run the Application

For Full Screen

Go to property window of MainWindow.xaml

• find WindowState property from Common category
• select Maximized option from dropdown
• Run the Application

Answer 3

I had to combine a few of these answers to cover all bases in my case:

• Peter's method to find the current monitor - rather than the just the Primary monitor (seriously who has just 1 monitor at work anymore?)
• @Wild_A's method to use the workarea rather than the screen bounds to take into account the space for the taskbar.
• I had to add DPI scaling, specifically for a tablet displaying 1280x800 as 1024x640, but which is useful to cover edge cases, for which I found an answer for here. Note the dpiScaling variable is null if called on first load before the UI is displayed (explained here)

//get the current monitor
Screen currentMonitor = Screen.FromHandle(new System.Windows.Interop.WindowInteropHelper(Application.Current.MainWindow).Handle);

//find out if our app is being scaled by the monitor
PresentationSource source = PresentationSource.FromVisual(Application.Current.MainWindow);
double dpiScaling = (source != null && source.CompositionTarget != null ? source.CompositionTarget.TransformFromDevice.M11 : 1);

//get the available area of the monitor
Rectangle workArea = currentMonitor.WorkingArea;
var workAreaWidth = (int)Math.Floor(workArea.Width*dpiScaling);
var workAreaHeight = (int)Math.Floor(workArea.Height*dpiScaling);

//move to the centre
Application.Current.MainWindow.Left = (((workAreaWidth - (myWindowWidth * dpiScaling)) / 2) + (workArea.Left * dpiScaling));
Application.Current.MainWindow.Top = (((workAreaHeight - (myWindowHeight * dpiScaling)) / 2) + (workArea.Top * dpiScaling));

where myWindowWidth and myWindowHeight are variables I used to manually set the size of the window earlier.

Answer 4

Isn't it just as simple to set

WindowStartupLocation="CenterScreen"

In the XAML definition for the window.

Answer 5

In the window element just add this attribute-value pair: WindowStartupLocation="CenterScreen"

Answer 6

private void CenterWindowOnScreen()
{
    double screenWidth = System.Windows.SystemParameters.PrimaryScreenWidth;
    double screenHeight = System.Windows.SystemParameters.PrimaryScreenHeight;
    double windowWidth = this.Width;
    double windowHeight = this.Height;
    this.Left = (screenWidth / 2) - (windowWidth / 2);
    this.Top = (screenHeight / 2) - (windowHeight / 2);
}

You can use this method to set the window position to the center of your screen.