how can i capture mupltiple keypresses on C# windows application?

[andkar]

hi all
im trying to capture multiple key passes like up arrow + left arrow
is there any way to do that with a key event or i have to write my own code
thank you

[Plater]

Well they will throw seperate keydown events, that could be helpfull? (Actually I think they continuously to throw keydown events)

[joedeene]

Well, I'm thinking that you'd have to use the KeyEventArgs class and some code to catch multiple events, like whenever the key is down set a boolean to true, and when the key is up set the boolean to false? And each time the key is pressed, after setting the booleans' value(s), have an if statement to see if two are down at the same time, although there are simpler ways.

joedeene

[mansuri]

You have to do some keyboard hooking to get all events. I am pasting some code from my app where I am doing it. Its not working code but you will have idea

private const int WH_KEYBOARD_LL = 13;
private const int WM_KEYDOWN = 0x0100;
private static LowLevelKeyboardProc _proc = HookCallback;
private static IntPtr _hookID = IntPtr.Zero;


[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr SetWindowsHookEx(int idHook,
LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UnhookWindowsHookEx(IntPtr hhk);

[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
IntPtr wParam, IntPtr lParam);

[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern IntPtr GetModuleHandle(string lpModuleName);

public static void Start()
{
_hookID = SetHook(_proc);

}
public static void Stop()
{
UnhookWindowsHookEx(_hookID);
}


private static IntPtr SetHook(LowLevelKeyboardProc proc)
{
using (Process curProcess = Process.GetCurrentProcess())
using (ProcessModule curModule = curProcess.MainModule)
{
return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
GetModuleHandle(curModule.ModuleName), 0);
}
}

private delegate IntPtr LowLevelKeyboardProc(
int nCode, IntPtr wParam, IntPtr lParam);

private static IntPtr HookCallback(
int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
{
int vkCode = Marshal.ReadInt32(lParam);
string keycode = (Keys)vkCode; }
return CallNextHookEx(_hookID, nCode, wParam, lParam);
}

[andkar]

Well, I'm thinking that you'd have to use the KeyEventArgs class and some code to catch multiple events, like whenever the key is down set a boolean to true, and when the key is up set the boolean to false? And each time the key is pressed, after setting the booleans' value(s), have an if statement to see if two are down at the same time, although there are simpler ways.

joedeene

what kind of simpler ways???

[IanWright]

what kind of simpler ways???

That is a simple way....

public void KeyDown(object sender, KeyEventArgs e)
{
if(e.KeyCode == Keys.Left)
{
// do something
}
else if (e.KeyCode == Keys.Right)
{
// do something else
}
}