C# How to Select an Open Application Window

Question

I'm trying to create a basic macro recording/playback system. If I wanted to select an open application (like notepad) to bring it to the front for input, how would I go about calling it by name or some other referanceable attribute?

Answer 1

You can start by using Process.GetProcesses - this will give you a list of all running processes. Examine the different properties on each process - this should get you going.

Answer 2

Checkout an app named "Autohotkey", it does everything you need and saves you a lot of programming time, and it's free.

If autohotkey doesn't solve your problems or if you're doing this for learning purposes, someone asked a "brand-new" app, etc., there are some links that may be helpful:

http://stackoverflow.com/questions/2987/bringing-window-to-the-front-in-c-using-win32-api http://social.msdn.microsoft.com/Forums/en-US/vssmartdevicesvbcs/thread/92823775-29f6-4950-bf06-d2f1ca89ec8d (it says "mobile windows" but still can be helpful)

Hope it helps.

Answer 3

Here is an example. Basically, get the Process, then call SetForegroundWindow on it's MainWindowHandle:

using System;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;

namespace StackOverflow.Test
{
    class Program
    {
        static void Main(string[] args)
        {
            var proc = Process.GetProcessesByName("notepad").FirstOrDefault();
            if (proc != null && proc.MainWindowHandle != IntPtr.Zero)
                    SetForegroundWindow(proc.MainWindowHandle);
        }

        [DllImport("user32")]
        private static extern bool SetForegroundWindow(IntPtr hwnd);
    }
}

You should be aware of the restrictions:

The system restricts which processes can set the foreground window. A process can set the foreground window only if one of the following conditions is true:

• The process is the foreground process.
• The process was started by the foreground process.
• The process received the last input event.
• There is no foreground process.
• The foreground process is being debugged.
• The foreground is not locked (see LockSetForegroundWindow).
• The foreground lock time-out has expired (see SPI_GETFOREGROUNDLOCKTIMEOUT in SystemParametersInfo).
• No menus are active.