SendInput Alt/Control/Shift Keys not getting Released

[Parveen Singla]

Hi,

I am using the below code to pass special keys using SendInput. I am facing one strange issue. If user sends any of Alt/Ctrl/Shift, the key remains pressed e.g. if user passes Alt + F4, the code runs properly and action is completed successfully but Alt key remains pressed. I need to manually click Alt key after the operation is completed. Please let me know to handle the same in the code itself. Below is the code used to send special keys.

class Program
{
static void Main(string[] args)
{
Thread.Sleep(3000);
int[] keyboardStrokes = { (int)Keys.LMenu, (int)Keys.Tab, (int)Keys.Tab };
ProcessKey(keyboardStrokes);
Console.Read();
}
struct INPUT
{
public INPUTType type;
public INPUTUnion Event;
}

[StructLayout(LayoutKind.Explicit)]
struct INPUTUnion
{
[FieldOffset(0)]
internal MOUSEINPUT mi;
[FieldOffset(0)]
internal KEYBDINPUT ki;
[FieldOffset(0)]
internal HARDWAREINPUT hi;
}

[StructLayout(LayoutKind.Sequential)]
struct MOUSEINPUT
{
public int dx;
public int dy;
public int mouseData;
public int dwFlags;
public uint time;
public IntPtr dwExtraInfo;
}

[StructLayout(LayoutKind.Sequential)]
struct KEYBDINPUT
{
public ushort wVk;
public ushort wScan;
public KEYEVENTF dwFlags;
public int time;
public IntPtr dwExtraInfo;
}

[StructLayout(LayoutKind.Sequential)]
struct HARDWAREINPUT
{
public int uMsg;
public short wParamL;
public short wParamH;
}

enum INPUTType : uint
{
INPUT_KEYBOARD = 1
}

[Flags]
enum KEYEVENTF : uint
{
EXTENDEDKEY = 0x0001,
KEYUP = 0x0002,
SCANCODE = 0x0008,
UNICODE = 0x0004
}

[DllImport("user32.dll", SetLastError = true)]
static extern UInt32 SendInput(int numberOfInputs, INPUT[] inputs, int sizeOfInputStructure);
[System.Runtime.InteropServices.DllImport("user32.dll")]
internal static extern uint MapVirtualKey(uint uCode, uint uMapType);

private static void ProcessKey(int[] key)
{
INPUT[] inputs = new INPUT[key.Length + 1];
for (int i = 0; i < key.Length; i++)
{
uint skey = MapVirtualKey((uint)key, (uint)0x0);
inputs.type = INPUTType.INPUT_KEYBOARD;
inputs.Event.ki.dwFlags = KEYEVENTF.SCANCODE;
inputs.Event.ki.wScan = (ushort)skey;
}
inputs[key.Length].type = INPUTType.INPUT_KEYBOARD;
inputs[key.Length].Event.ki.dwFlags = KEYEVENTF.UNICODE;
inputs[key.Length].Event.ki.dwFlags |= KEYEVENTF.KEYUP;
uint cSuccess = SendInput(inputs.Length, inputs, Marshal.SizeOf(typeof(INPUT)));
}


Regards, Parveen

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