rdp-portal/MainForm.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace RDP_Portal {
    public partial class MainForm : Form {
        public MainForm() {
            InitializeComponent();
        }

        private void buttonMoreOptions_Click(object sender, EventArgs e) {
            ProcessStartInfo startInfo = new ProcessStartInfo {
                CreateNoWindow = false,
                UseShellExecute = false,
                FileName = "mstsc.exe",
                Arguments = "/edit test.rdp"
            };

            try {
                var exeProcess = Process.Start(startInfo) ?? throw new InvalidOperationException();
                exeProcess.WaitForExit();
            } catch (Exception ex) {
                MessageBox.Show(ex.ToString());
            }
        }
    }
}