Updating a specific rdp file so that the screen indexes for the selectedmonitors parameter are adjusted correctly.

UpdateMstscWithScreens.cs

#! dotnet run 
#:sdk Microsoft.NET.Sdk
#:property UseWindowsForms True
#:property TargetFramework net10.0-windows

using System.Windows.Forms;
var screens = Screen.AllScreens.Select(scr => (Screen: scr, Index : int.Parse(scr.DeviceName.Split("DISPLAY").Last()) - 1));

int firstScreenIdx = -1;
List<int> otherScreens = [];

foreach (var scr in screens.Where(x => x.Screen.WorkingArea.X >= 0).OrderBy(x => x.Index))
{
    if (scr.Screen.WorkingArea.X == 0 && scr.Screen.WorkingArea.Y == 0)
    {
        firstScreenIdx = scr.Index;
    }
    else
    {
        otherScreens.Add(scr.Index);
    }
    //Console.WriteLine($"{scr.Index} : {scr.Screen.WorkingArea}    {scr.Screen.DeviceName}");
}

var fileName = @"C:\Users\Alexa\OneDrive\Desktop\codierdpalex ALLSCREENS 1.rdp";
var lines = File.ReadAllLines(fileName, System.Text.Encoding.Unicode).ToList();
var selectedmonitorsLine = lines.First(l => l.StartsWith("selectedmonitors:s:"));
var lineIndex = lines.IndexOf(selectedmonitorsLine);
lines[lineIndex] = $"selectedmonitors:s: {firstScreenIdx},{string.Join(",", otherScreens)}";

File.WriteAllLines(fileName, lines, System.Text.Encoding.Unicode);