change windowstyle of a running process

Sorry spoke to soon. got it to work

1st convert to long

then type cast the long to Intptr ;)

sorry but next question .. im saving the HWND to text file as the main gui can be closed. how does one convert string to Intptr ?

Thanks

I was trying something similar to that earlier .. but proc.windowhandle() always returned 0, untill i used that WaitForInputIdle(), program doesnt have an input but put a try block around it ignoring error worked with out me having to sleep the thread ;)

No, I don't think there's any managed alternative to ShowWindow when you're dealing with external processes. However, I have thought of a managed way to get the window handle of a hidden window which is to start the window as normal, get the handle and then hide it :)

When I ran this test program using wordpad, this approach worked quickly enough for wordpad not to have chance to open its window until I forced it to display after a 5 seconds delay:

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;

class Program
{
    
     [DllImport("user32.dll")]
     private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

     private const int SW_HIDE = 0;
     private const int SW_SHOW = 5;

     static void Main()
     {
        Process proc = new Process();
        proc.StartInfo.FileName = "wordpad.exe";
        proc.StartInfo.WindowStyle = ProcessWindowStyle.Normal;
        proc.Start();
        proc.WaitForInputIdle(); // wait until process has initialized
        IntPtr hWnd = proc.MainWindowHandle;
        ShowWindow(hWnd, SW_HIDE);
        Thread.Sleep(5000); // wait 5 secs before displaying
        ShowWindow(hWnd, SW_SHOW);
        proc.WaitForExit();         
     }
}

Thanks

I was hoping i didnt have to use that API and that c# had somethin like that.

If you can get a handle to the window, then you can call the API function ShowWindow(hWnd, SW_SHOW) to make it visible.

However, the problem is getting a handle to the window in the first place as I think Process.MainWindowHandle always returns IntPtr.Zero for windows which are hidden when they're created. You could try the API function FindWindow instead.

Here are some declarations that you'll need for all this:

using System.Runtime.InteropServices;

........

[DllImport("user32.dll")]
private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

[DllImport("user32.dll")]
private static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);

private const int SW_SHOW = 5;