[c#] How can I run another application within a panel of my C# program?

I've been reading lots on how to trigger an application from inside a C# program (Process.Start()), but I haven t been able to find any information on how to have this new application run within a panel of my C# program. For example, I'd like a button click to open a notepad.exe WITHIN my application, not externally.

I notice that all the prior answers use older Win32 User library functions to accomplish this. I think this will work in most cases, but will work less reliably over time.

Now, not having done this, I can't tell you how well it will work, but I do know that a current Windows technology might be a better solution: the Desktop Windows Manager API.

DWM is the same technology that lets you see live thumbnail previews of apps using the taskbar and task switcher UI. I believe it is closely related to Remote Terminal services.

I think that a probable problem that might happen when you force an app to be a child of a parent window that is not the desktop window is that some application developers will make assumptions about the device context (DC), pointer (mouse) position, screen widths, etc., which may cause erratic or problematic behavior when it is "embedded" in the main window.

I suspect that you can largely eliminate these problems by relying on DWM to help you manage the translations necessary to have an application's windows reliably be presented and interacted with inside another application's container window.

The documentation assumes C++ programming, but I found one person who has produced what he claims is an open source C# wrapper library: https://bytes.com/topic/c-sharp/answers/823547-desktop-window-manager-wrapper. The post is old, and the source is not on a big repository like GitHub, bitbucket, or sourceforge, so I don't know how current it is.

Another interesting solution to luch an exeternal application with a WinForm container is the follow:

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


private void Form1_Load(object sender, EventArgs e)
{
    ProcessStartInfo psi = new ProcessStartInfo("notepad.exe");
    psi.WindowStyle = ProcessWindowStyle.Minimized;
    Process p = Process.Start(psi);
    Thread.Sleep(500);
    SetParent(p.MainWindowHandle, panel1.Handle);
    CenterToScreen();
    psi.WindowStyle = ProcessWindowStyle.Normal;
}

The step to ProcessWindowStyle.Minimized from ProcessWindowStyle.Normal remove the annoying delay.

Using the win32 API it is possible to "eat" another application. Basically you get the top window for that application and set it's parent to be the handle of the panel you want to place it in. If you don't want the MDI style effect you also have to adjust the window style to make it maximised and remove the title bar.

Here is some simple sample code where I have a form with a button and a panel:

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

namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            Process p = Process.Start("notepad.exe");
            Thread.Sleep(500); // Allow the process to open it's window
            SetParent(p.MainWindowHandle, panel1.Handle);
        }

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

I just saw another example where they called WaitForInputIdle instead of sleeping. So the code would be like this:

Process p = Process.Start("notepad.exe");
p.WaitForInputIdle();
SetParent(p.MainWindowHandle, panel1.Handle);

The Code Project has a good article one the whole process: Hosting EXE Applications in a WinForm project

I know this is possible if the other application can attach itself to a win32 window handle. For example, we have a separate C# application that hosts a DirectX application inside one of its windows. I'm not familiar with the exact details of how this is implemented, but I think just passing the win32 Handle of your panel to the other application is enough for that application to attach its DirectX surface.

• Adding some solution in Answer..**

This code has helped me to dock some executable in windows form. like NotePad, Excel, word, Acrobat reader n many more...

But it wont work for some applications. As sometimes when you start process of some application.... wait for idle time... and the try to get its mainWindowHandle.... till the time the main window handle becomes null.....

so I have done one trick to solve this

If you get main window handle as null... then search all the runnning processes on sytem and find you process ... then get the main hadle of the process and the set panel as its parent.

        ProcessStartInfo info = new ProcessStartInfo();
        info.FileName = "xxxxxxxxxxxx.exe";
        info.Arguments = "yyyyyyyyyy";
        info.UseShellExecute = true;
        info.CreateNoWindow = true;
        info.WindowStyle = ProcessWindowStyle.Maximized;
        info.RedirectStandardInput = false;
        info.RedirectStandardOutput = false;
        info.RedirectStandardError = false;

        System.Diagnostics.Process p = System.Diagnostics.Process.Start(info); 

        p.WaitForInputIdle();
        Thread.Sleep(3000);

        Process[] p1 ;
    if(p.MainWindowHandle == null)
    {
        List<String> arrString = new List<String>();
        foreach (Process p1 in Process.GetProcesses())
        {
            // Console.WriteLine(p1.MainWindowHandle);
            arrString.Add(Convert.ToString(p1.ProcessName));
        }
        p1 = Process.GetProcessesByName("xxxxxxxxxxxx");
        //p.WaitForInputIdle();
        Thread.Sleep(5000);
      SetParent(p1[0].MainWindowHandle, this.panel2.Handle);

    }
    else
    {
     SetParent(p.MainWindowHandle, this.panel2.Handle);
     }

No

Only if the other application is designed to allow it, by providing components for you to add into your own application.

If you want to run notepad inside your app you would probably be better of with a text editor component. There's obviously a basic text box that comes with WinForms, but I suspect more advanced components that offer Notepad functionality (or better) can be found on the interweb.