Win32Api windows move - winapi

Question

how i can move my window when middle mouse button pressed?
in case with left mouse button it would be
case WM_LBUTTONDOWN:
{
SendMessage(hwnd, WM_NCLBUTTONDOWN, HTCAPTION, 0);
}
return 0;
but it does not work with middle button
case WM_MBUTTONDOWN:
{
SendMessage(hwnd, WM_NCMBUTTONDOWN, HTCAPTION, 0);
}
return 0;
but i am not sure about WM_NCMBUTTONDOWN
i`m out of variants, need help please

Answer 1

You have to do this the hard way I'm afraid. I tried all the obvious things and WM_NCHITTEST doesn't cut it if you want to drag the window with anything other than the left mouse button.
Here's some code that works for me (tested on Windows 10). I've excluded error checking for brevity:
#include <windows.h>
#include <windowsx.h>
#include <tchar.h>
// WndProc
LRESULT CALLBACK MyWndProc (HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
static int xClick, yClick;
switch (uMsg)
{
case WM_NCMBUTTONDOWN:
case WM_LBUTTONDOWN:
case WM_MBUTTONDOWN:
{
SetCapture (hWnd);
POINT pt = { GET_X_LPARAM (lParam), GET_Y_LPARAM (lParam) };
if (uMsg == WM_NCMBUTTONDOWN)
ScreenToClient (hWnd, &pt);
xClick = pt.x;
yClick = pt.y;
return 0;
}
case WM_LBUTTONUP:
case WM_MBUTTONUP:
ReleaseCapture ();
return 0;
case WM_MOUSEMOVE:
{
if (GetCapture() == hWnd)
{
RECT wr;
GetWindowRect (hWnd, &wr);
int xMouse = GET_X_LPARAM (lParam);
int yMouse = GET_Y_LPARAM (lParam);
int xWindow = wr.left + xMouse - xClick;
int yWindow = wr.top + yMouse - yClick;
SetWindowPos (hWnd, NULL ,xWindow, yWindow, 0, 0 , SWP_NOSIZE | SWP_NOZORDER);
}
return 0;
}
}
return DefWindowProc (hWnd, uMsg, wParam, lParam);
}
// WinMain
int CALLBACK _tWinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPTSTR lpCmdLine, int nCmdShow)
{
HINSTANCE hInstance = NULL;
WNDCLASS wc = { };
wc.lpszClassName = __T ("MyWindowClass");
wc.lpfnWndProc = MyWndProc;
RegisterClass (&wc);
HWND hWnd = CreateWindow (wc.lpszClassName, __T ("My Window"),
WS_CAPTION | WS_BORDER | WS_VISIBLE, 100, 100, 200, 200, NULL, NULL, hInstance, 0);
MSG msg;
while (GetMessage (&msg, NULL, 0, 0))
DispatchMessage (&msg);
return 0;
}
Hope this helps.