I am using Visual Studio 2022 and I have created a VSTO Word Add-In project.

I want to open a new form with a button inside my ribbon. However, my form always starts in the top left corner of my primary screen, which is problematic if the Word document is on a different screen.

In my case, my Word document usually opens on my second screen, so I need the form to dynamically start on the same screen as the Word document.

So far, I have been able to change the starting position of my form using the myForm.Location and myForm.StartPosition properties, as shown below. But how do I get the screen which my Word application is using?

using Word = Microsoft.Office.Interop.Word;

namespace WordTabellenAddIn
{
    public partial class RibbonWordAddIn
    {

        private void TabellenButton_Click(object sender, RibbonControlEventArgs e)
        {
            Word.Document ThisDocument = Globals.ThisAddIn.Application.ActiveDocument;
            //Screen screen = Screen.FromControl(ThisDocument); <-- Expects a "System.Windows.Forms.Control" Which the Object simply isn't

            var myForm = new FormFenster();
            myForm.Location = Screen.AllScreens[1].WorkingArea.Location;
            myForm.StartPosition = FormStartPosition.CenterScreen;
            myForm.ShowDialog();
        }
    }
}

So far I looked into the official Word interface documentation for the Word.Document class
MS Documentation but couldn’t find a clue.