WPF Maximized Window bigger than screen

Question

When creating a WPF window with AllowsTransparency="True" WindowStyle="None" and maximizing it via this.WindowState = WindowState.Maximized; the Window gets bigger than my screen.

When setting AllowTransparency="False" i have a border around my Window, but the window won't get bigger than my screen.
In my Case I have a 1920x1080 screen and the window becomes 1934x1094.
On my 1280x1024 screen the window will become 1294x1038.
The Window will become still as big as this, whether or not AllowTransparency is enabled or not, yet with it disabled it works properly.

Setting AllowTransparency before maximizing doesen't work and throws an InvalidOperationException.

How to get a WPF window without a Windows-style border, but yet to maximize properly?

Answer 1

A couple year late to the party but just increase your this.borderthickness for the SizeChanged event like so:

<Window x:Class="MyApp.MainWindow"
    ResizeMode="CanResize" 
    WindowStyle="SingleBorderWindow"
    SizeChanged="Window_SizeChanged">
....
Code
....
</Window>


public void Window_SizeChanged(object sender, SizeChangedEventArgs e)
    {
        if (this.WindowState == WindowState.Maximized)
        {
            this.BorderThickness = new System.Windows.Thickness(8);
        }
        else
        {
            this.BorderThickness = new System.Windows.Thickness(0);
        }
    }

Answer 2

It seems a pretty common issue. It appears you'll have to bind your height and width to the actual height/width of the screen as stated in this StackOverflow post:

Borderless window application takes up more space than my screen resolution.

I hope that solves the issue you're facing.