Question

I’m using Visual Basic 2008

for example i have running notepad.exe, can i hide notepad window, and then if i need it to show it again?

thanks.

Answer 1

• Call Process.GetProcessesByName() passing "notepad".
• Then read MainWindowHandle from the returned process.
• P/Invoke ShowWindow() passing SW_HIDE or SW_SHOW to hide/show the window.

The P/Invoke signature is:

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function ShowWindow(ByVal hwnd As IntPtr, ByVal nCmdShow As Integer) As Boolean
End Function

The ShowWindow() topic lists the numeric values for the SW_* flags.

---

Thanks to @Alex K for suggesting as a comment the use of ShowWindowAsync() rather than ShowWindow().

<DllImport("user32.dll", SetLastError:=True, CharSet:=CharSet.Auto)> _
Private Shared Function ShowWindowAsync(ByVal hwnd As IntPtr, ByVal nCmdShow As Integer) As Boolean
End Function

From the documentation:

This function posts a show-window
event to the message queue of the
given window. An application can use
this function to avoid becoming
nonresponsive while waiting for a
nonresponsive application to finish
processing a show-window event.