ShowWindow is unable to show or minimize Task Manager

Question

I need to show Task Manager app programatically, maximize it and minimize it as any other window but there is a problem and it simply doesn't respond to ShowWindow(int hWnd, int nCmdShow).

I am pretty sure I use the correct handle because I enumerated all of the windows with EnumWindows(PCallBack callback, int lParam) and the only window that didn't respond was the task manager window with title process.MainWindowTitle = "Task Manager", I even manually found its handle using spy++ but it still doesn't respond to SW_SHOWNORMAL or any other nCmdShow parameter. I tried running apps as administrator to see if it has something to do with the issue but they kept behaving like normal when proper handle was given to ShowWindow function;

private delegate bool PCallBack(int hWnd, int lParam);

private static void ShowWindows()
{
    EnumWindows(new PCallBack(FindWindows), 0);
}

private bool FindWindows(int handle, int lparam)
{
    Console.WriteLine("showing");
    ShowWindow(handle, (int)SW.SHOWMINIMIZED);
    ShowWindow(handle, (int)SW.SHOWNORMAL);
    Thread.Sleep(3000);

    return true;
}

static void Main(string[] args)
{
    ShowWindows();
}

This code literally shows every window EnumWindows can find even if they are not visible and task manager was never shown which proved to me that the problem has nothing to do with wrong handle. This is how I find it by the way.

// the correct handle of Task Manager window
var handle = (int)Process.GetProcessesByName("taskmgr").FirstOrDefault().MainWindowHandle;

Basically this is my problem. Need help.

I just added some code I used to get to the conclusions stated above. — Santi6, Mar 28 '19 at 22:26
Task Manager seems like a special window. By the way, those parameters should be IntPtr. — LarsTech, Mar 28 '19 at 23:51
Of course that isn't possible, the virus writers would instantly exploit this. Just one of the basic goodies we get from UAC, Task Manager always runs elevated. — Hans Passant, Mar 29 '19 at 21:53

score 0 · Answer 1 · answered Jun 18 '19 at 10:05

it simply doesn't respond to ShowWindow(int hWnd, int nCmdShow).

I tested on Windows 10 and this works for me :

Manifest file with level="requireAdministrator"

Test :

IntPtr hWndTarget = FindWindow("TaskManagerWindow", null);
bool bRet = ShowWindow(hWndTarget, SW_SHOWMINIMIZED);

with declarations :

[DllImport("User32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

[DllImport("User32.dll", SetLastError = true, CharSet = CharSet.Auto)]
public static extern bool ShowWindow(IntPtr hWnd, int nCmdShow);
public const int SW_HIDE = 0;
public const int SW_SHOWNORMAL = 1;
public const int SW_SHOWMINIMIZED = 2;
public const int SW_SHOWMAXIMIZED = 3;

ShowWindow is unable to show or minimize Task Manager

1 Answers1