sendmessage with shift, control, alt key combinations

Question

I'm trying to send Key combinations like Shift F8, etc to a specific window. I am able to send F8 by itself by posing a WM_KEYDOWN, then a WM_KEYUP and specifing (int)System.Windows.Forms.Keys.F8 as the wParam, but can't figure out how to do it with the shift key. I've tried ORing it with System.Windows.Forms.Keys.SHIFT as well as System.Windows.Forms.Keys.SHIFTKEY but that doesn't seem to work. Is there some other way?

Note that I can't use SendInput or possibly because they don't take window handles, and my window may not be in the foreground. Any suggestions appreciated...

Answer 1

Send individual WM_KEYDOWN messages, one for each key pressed.

WM_KEYDOWN -> Shift

WM_KEYDOWN -> F8

WM_KEYUP -> F8

WM_KEYUP -> Shift

Here is a message capture from Spy++ of the message sequence when pressing shift+f8 in notepad.

WM_KEYDOWN nVirtKey:VK_SHIFT cRepeat:1 ScanCode:36 fExtended:0 fAltDown:0 fRepeat:0 fUp:0

WM_KEYDOWN nVirtKey:VK_F8 cRepeat:1 ScanCode:42 fExtended:0 fAltDown:0 fRepeat:0 fUp:0

WM_KEYUP nVirtKey:VK_F8 cRepeat:1 ScanCode:42 fExtended:0 fAltDown:0 fRepeat:1 fUp:1

WM_KEYUP nVirtKey:VK_SHIFT cRepeat:1 ScanCode:36 fExtended:0 fAltDown:0 fRepeat:1 fUp:1

Answer 2

This should do the trick:

if (e.Shift && e.KeyCode == Keys.F8)
{
    MessageBox.Show("hello");
}

Answer 3

You must use keybd_event or SendInput to send modifier keys to another application because of the way windows handles modifier keys (fun, yes?). I think both may require the other application to have focus to work correctly.

Just sending a series of keydowns / keyups as if you were pushing and holding the modifier keys doesn't (or, at least, didn't last I tried it) work since most applications poll for those keys separately instead of listening for messages about them. I suppose if you control the source for both applications this may work.