C# switching windows in .net

Question

Hi I'm trying to switch windows to other programs that are running (even if minimized) using C#.

I'm wondering why this won't work.

Error message: Argument 1: cannot convert from 'System.Diagnostics.Process' to 'System.IntPtr'

By the time it hits the loop I would think that the proc variable would refer to the appropriate window handler. Is this not true? I really appreciate the help.

//declarations
using system.IO;
using System.Runtime.InteropServices;
//more

//namespace here

//class here

//initialize method

//related .dll import
[DllImport("user32.dll")]
        public static extern void SwitchToThisWindow(IntPtr hWnd);

String ProcWindow = "itunes";
//function which calls switchWindow() is here but not important

//now we have switch window.
private void switchWindow()
        {
            Process[] procs = Process.GetProcessesByName(ProcWindow);
            foreach (Process proc in procs)
            {
                //switch to process by name
                SwitchToThisWindow(proc);

            }
        }

For future readers: I got to this point in my code from another question. Correct way (in .NET) to switch the focus to another application

The process object isn't the process handle (which an intptr). Look here: http://stackoverflow.com/questions/1276629/c-sharp-get-running-process-given-process-handle — jwrush, Aug 21 '13 at 18:00

score 5 · Accepted Answer · answered Aug 21 '13 at 18:03

5

SwitchToThisWindow is expecting a handle to the window that you want to switch to in that process.

Try

SwitchToThisWindow(proc.MainWindowHandle);

answered Aug 21 '13 at 18:03

Doug Morrow

1,306
1
10
18

Awesome, so it has properties I can access. – camdixon Aug 21 '13 at 18:06
What else can you get by doing proc.? Is there a good article on it? – camdixon Aug 21 '13 at 18:06
Absolutely, MSDN will always be your best resource: http://msdn.microsoft.com/en-us/library/system.diagnostics.process.aspx – Doug Morrow Aug 21 '13 at 18:08

score 5 · Answer 2 · answered Aug 21 '13 at 18:05

5

I believe what you want is:

[DllImport("user32.dll")]
public static extern void SwitchToThisWindow(IntPtr hWnd, bool turnon);

String ProcWindow = "itunes";
//function which calls switchWindow() is here but not important

//now we have switch window.
private void switchWindow()
{
  Process[] procs = Process.GetProcessesByName(ProcWindow);
  foreach (Process proc in procs)
  {
     //switch to process by name
     SwitchToThisWindow(proc.MainWindowHandle, false);

  }
}

SwitchToThisWindow expects an IntPtr that is a handle to a window, not a process which is what you were trying to pass in.

Also note that your pinvoke signature for SwitchToThisWindow appeared to be incorrect, you were missing the bool parameter.

answered Aug 21 '13 at 18:05

chris.house.00

3,273
1
27
36

Boolean parameter should be false. http://msdn.microsoft.com/en-us/library/windows/desktop/ms633553%28v=vs.85%29.aspx – Sriram Sakthivel Aug 21 '13 at 18:08
1

Noted, I have updated it. Thanks for helping me improve my code. I appreciate the article too, so I can understand why it should be false. – camdixon Aug 21 '13 at 18:18
Another quick related question. How can I detect through the api if the window is open? If it is, then I will call this function – camdixon Aug 21 '13 at 18:46

C# switching windows in .net

2 Answers2