C#

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

namespace putty
{
    public partial class Form1 : Form
    {

        public int tabp = 0;
        public Panel panel;
        public string select;
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, int wParam, int lParam);

        [DllImport("user32.dll", SetLastError = true)]
        static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

        public Form1()
        {
            
            InitializeComponent();
        }

        private void button3_Click(object sender, EventArgs e)
        {
            listBox1.Items.Clear();
            //string folder = connections\\";
            string[] files = Directory.GetFiles("connections\\", "*.bat");

            listBox1.Items.AddRange(files);
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            txtbatch.Clear();
            txtbatch.Text += "C:/plink.exe -v -ssh " + txtusr.Text + "@" + txtip.Text + " -pw " + txtpass.Text;
            File.WriteAllText(@"connections\\" +txtname.Text+".bat", txtbatch.Text);
            MessageBox.Show("Please Refresh");
        }




        public void button1_Click(object sender, EventArgs e)
        {
            TabPage page = new TabPage(); //create our IContainer/TabPage
            Panel panel= new Panel(); //create our button
            panel.Dock = DockStyle.Fill; //make our button fill up the tab page when added
          //  button.Click += new EventHandler(button_Click); //this adds the below button_Click event
          
            tabControl1.TabPages.Add(page); //add our tab page to the tab control
            tabControl1.SelectedTab = page; //make our tab the selected tab


            cmd(panel); // run the cmd start up
        }


        public void cmd(Panel panel)
        {
            select = listBox1.Text;

            const int WM_SYSCOMMAND = 0x112;
            const int SC_MINIMIZE = 0xF020;
            const int SC_MAXIMIZE = 0xF030;

            Process p = Process.Start(
                       new ProcessStartInfo()
                       {
                           FileName = select, //runs the file selected in cmd
                           WindowStyle = ProcessWindowStyle.Minimized
                       });
            Thread.Sleep(500);
            IntPtr value = SetParent(p.MainWindowHandle, panel.Handle); // cant find panel
            SendMessage(p.MainWindowHandle, WM_SYSCOMMAND, SC_MAXIMIZE, 0);
        }

    }
}