Send mouse wheel click properly (SendInput MouseEventFlag MiddleDown/ Up)

Question

Hello,
I tested it a few hours but i can't figure it out and i couldn't find something on the internet.
https://learn.microsoft.com/en-us/windows/win32/api/winuser/ns-winuser-mouseinput

The problem is that when I test it, it has a variety of misbehavior; until I have to restart my PC because I can no longer click the left mouse button properly.

Do i have to use the MiddleDown and MiddleUp separated depending on the keystate or something like that?

For i.e.: Clicking the browser the 1st time (MiddleDown - if keystate up) to get this weird arrow (i don't know the name for this control) and a 2nd click (MiddleUp - if keystate down) to remove the arrow.

Sorry, can't post the code, i'm getting the following error:
WAF v2 has determined your request exceeded the normal web request and has blocked your request.

I forgot to say: If i'm using the code above, it starts laging when i use it multiple times in a row and causes the misbehaviour.

Regards

Answer 1

This test with MS Edge seems to work fine for me (I get the mouse wheel cursor, if the current page can be scrolled) =>

IntPtr hWndEdge = IntPtr.Zero;
Process[] procsEdge = Process.GetProcessesByName("msedge");
if (procsEdge.Length <= 0)
{
    Console.WriteLine("MS Edge is not running");
}
else
{
    foreach (Process proc in procsEdge)
    {
        if (proc.MainWindowHandle == IntPtr.Zero)
        {
            continue;
        }
        else
        {
            hWndEdge = proc.MainWindowHandle;
            break;
        }
    }
}
if (hWndEdge != IntPtr.Zero)
{
    SwitchToThisWindow(hWndEdge, true);

    RECT rc = new RECT();
    GetWindowRect(hWndEdge, out rc);

    int nScreenWidth = GetSystemMetrics(SM_CXVIRTUALSCREEN);
    int nScreenHeight = GetSystemMetrics(SM_CYVIRTUALSCREEN);
    int nScreenLeft = GetSystemMetrics(SM_XVIRTUALSCREEN);
    int nScreenTop = GetSystemMetrics(SM_YVIRTUALSCREEN);

    int nXMove = rc.left + (rc.right - rc.left) / 2;
    int nYMove = rc.top + (rc.bottom - rc.top) / 2;
    int nX = (int)((((double)(nXMove) - nScreenLeft) * 65536) / nScreenWidth + 65536 / (nScreenWidth));
    int nY = (int)((((double)(nYMove) - nScreenTop) * 65536) / nScreenHeight + 65536 / (nScreenHeight));

    INPUT[] mi = new INPUT[3];
    mi[0].type = INPUT_MOUSE;
    mi[0].inputUnion.mi.dx = nX;
    mi[0].inputUnion.mi.dy = nY;
    mi[0].inputUnion.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MOVE;
    //mi[1].inputUnion.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTDOWN;
    //mi[2].inputUnion.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_LEFTUP;
    mi[1].inputUnion.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MIDDLEDOWN;
    mi[2].inputUnion.mi.dwFlags = MOUSEEVENTF_ABSOLUTE | MOUSEEVENTF_MIDDLEUP;                    

    SendInput(3, mi, Marshal.SizeOf(mi[0]));
}

Declarations :

[DllImport("User32.dll", SetLastError = true)]
public static extern bool GetWindowRect(IntPtr hWnd, out RECT lpRect);

[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
    public int left;
    public int top;
    public int right;
    public int bottom;
    public RECT(int Left, int Top, int Right, int Bottom)
    {
        left = Left;
        top = Top;
        right = Right;
        bottom = Bottom;
    }
}

[DllImport("User32.dll", SetLastError = true)]
public static extern bool SwitchToThisWindow(IntPtr hWnd, bool fAltTab);

[DllImport("User32.dll", SetLastError = false)]
public static extern IntPtr GetDesktopWindow();

public const int INPUT_MOUSE = 0;
public const int INPUT_KEYBOARD = 1;
public const int INPUT_HARDWARE = 2;

public const int MOUSEEVENTF_MOVE = 0x0001; /* mouse move */
public const int MOUSEEVENTF_LEFTDOWN = 0x0002; /* left button down */
public const int MOUSEEVENTF_LEFTUP = 0x0004; /* left button up */
public const int MOUSEEVENTF_RIGHTDOWN = 0x0008; /* right button down */
public const int MOUSEEVENTF_RIGHTUP = 0x0010; /* right button up */
public const int MOUSEEVENTF_MIDDLEDOWN = 0x0020; /* middle button down */
public const int MOUSEEVENTF_MIDDLEUP = 0x0040; /* middle button up */
public const int MOUSEEVENTF_XDOWN = 0x0080; /* x button down */
public const int MOUSEEVENTF_XUP = 0x0100; /* x button down */
public const int MOUSEEVENTF_WHEEL = 0x0800; /* wheel button rolled */
public const int MOUSEEVENTF_HWHEEL = 0x01000; /* hwheel button rolled */
public const int MOUSEEVENTF_MOVE_NOCOALESCE = 0x2000; /* do not coalesce mouse moves */
public const int MOUSEEVENTF_VIRTUALDESK = 0x4000; /* map to entire virtual desktop */
public const int MOUSEEVENTF_ABSOLUTE = 0x8000; /* absolute move */

[DllImport("User32.dll", SetLastError = true)]
public static extern int GetSystemMetrics(int nIndex);

public const int SM_XVIRTUALSCREEN = 76;
public const int SM_YVIRTUALSCREEN = 77;
public const int SM_CXVIRTUALSCREEN = 78;
public const int SM_CYVIRTUALSCREEN = 79;

public const int KEYEVENTF_EXTENDEDKEY = 0x0001;
public const int KEYEVENTF_KEYUP = 0x0002;
public const int KEYEVENTF_UNICODE = 0x0004;
public const int KEYEVENTF_SCANCODE = 0x0008;

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

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

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

[StructLayout(LayoutKind.Sequential)]
public struct INPUT
{
    public int type;
    public INPUTUNION inputUnion;
}

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

[DllImport("User32.dll", SetLastError = true)]
public static extern int SendInput(int nInputs, [MarshalAs(UnmanagedType.LPArray)] INPUT[] pInput, int cbSize);