Simulating Key Press c#

Question

I want to simulate F5 key press in my c# program, When IE is open I want to be able refresh my website automatically.

Answer 1

You can use the Win32 API FindWindow or FindWindowEx to find the window handle of the open browser and then just call SendMessage with WM_KEYDOWN. Typically it's easiest just to pass the window caption to FindWindowEx and have it find the associated window handle for you.

If you are starting the browser process yourself via a Process process object then you can use process.MainWindowHandle instead of calling FindWindowEx.

Spy++ is a very useful tool when you want to start working with other windows. It basically allows you to learn another program's hierarchy of UI elements. You can also monitor all of the messages that go into the window you're monitoring. I have more info in this thread.

The F5 keystroke has this virtual key code:

const int VK_F5 = 0x74;

The p/invoke signature for FindWindowEx in C# is:

[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindowEx(IntPtr hwndParent, IntPtr hwndChildAfter, string lpszClass, string lpszWindow);

You can p/invoke (bring in) the Win32 API SendMessage like this:

[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

So to recap, you call FindWindowEx directly from your C# code after having the above code somewhere inside your class. FindWindowEx will return a window handle. Then once you have the window handle, you can send any keystroke(s) to the window, or call many other Win32 API calls on the window handle. Or even find a child window by using another call to FindWindowEx. For example you could select the edit control of the browser even and then change it's text.

If all else goes wrong and you think you're sending the right key to the window, you can use spy++ to see what messages are sent to the window when you manually set focus to the browser and manually press F5.