How to simulate mouse clicks in a background program

Question

I’m like a problem to use the functions SendMessage and PostMessage in C# to simulate clicks mouse in a minimized program (in the background).

I used this code but it didn’t work, I believe it’s the makeparam .

 public enum WMessages : int
    {
        WM_LBUTTONDOWN = 0X201,
        WM_LBUTTONUP = 0x202,
        WM_LBUTTONBCLICK = 0x203,

        WM_RBUTTONDOWN = 0x204,
        WM_RBUTTONUP = 0x205,
        WM_BUTTONBCLICK = 0x206,
    }

    [DllImport("user32.dll")]
    static extern IntPtr WindowFromPoint(int xPoint, int yPoint);

    [DllImport("user32.dll", SetLastError = true)]
    public static extern IntPtr FindWindowsEx(IntPtr parentHendle, IntPtr childAfter, string className, IntPtr windowsTitle);

    [DllImport("user32.dll")]
    public static extern IntPtr FindWindows(String sClassName, String sAppName);

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

    [DllImport("user32.dll", SetLastError = true)]
    static extern bool PostMessage(IntPtr hWnd, int Msg, int wParam, int lParam);

    [DllImport("user32.dll")]
    public static extern int SetActiveWindows(IntPtr hwnd);

    [DllImport("user32.dll")]
    static extern bool SetForegroundWindow(IntPtr hWnd);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern int GetWindowText(IntPtr hWnd, StringBuilder lpString, int nMaxCount);

    [DllImport("user32.dll")]
    internal static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);

    public static IntPtr findme()
    {
        Process k = Process.GetProcessesByName("Nome do programa minimizado")[0];
        return k.MainWindowHandle;
    }

    private static int MAKELPARAM(int p, int p_2)
    {
        return ((p_2 << 16) | (p & 0xFFFF));
    }

    public static void clickMouseLeft(int x, int y)
    {
        IntPtr myHandle = findme();
        Point pt = new Point(x, y);
        IntPtr Handle = WindowFromPoint(pt.X, pt.Y);
        int lnglParam = (pt.Y * 0x10000) + pt.X;
        SetForegroundWindow(myHandle);
        SendMessage(Handle, (int)WMessages.WM_LBUTTONDOWN, 0, MAKELPARAM(pt.X,pt.Y));
        SendMessage(Handle, (int)WMessages.WM_LBUTTONUP, 0, MAKELPARAM(pt.X, pt.Y));
    }

This code below is a code I made in C++ that worked perfectly

cursorPos.x = ui->lineEdit_x->text().toInt();
cursorPos.y = ui->lineEdit_y->text().toInt();
HWND hwnd = FindWindow(NULL, L"Nome do programa minimizado");
DWORD dw = MAKEWORD(cursorPos.x, cursorPos.y);
SendMessage(hwnd, WM_LBUTTONDOWN, MK_LBUTTON, dw);
SendMessage(hwnd, WM_LBUTTONUP, MK_LBUTTON, dw);

Answer 1

Try using the Event mouse. Directive:

[DllImport("user32.dll")]
public static extern void mouse_event(uint dwFlags, int dx, int dy, uint dwData, int dwExtraInfo);

Use:

 mouse_event(MOUSEEVENTF_LEFTDOWN, 0, 0, 0, 0);
 mouse_event(MOUSEEVENTF_LEFTUP, 0, 0, 0, 0);