Win32 SDK程序中拖动Thin边框窗口来改变窗口大小

主要需要添加处理WM_NCHITTEST，WM_SETCURSOR和WM_NCLBUTTONDOWN消息

版本1.0（本版本有问题，右下角不响应消息）

case WM_NCHITTEST:
            POINT point;
            point.x = LOWORD(lParam);
            point.y = HIWORD(lParam);
            RECT rect;        
            GetWindowRect(hWnd,&rect);
            if(point.x <= rect.left+5)
            {
                 return HTLEFT;
            }
            else if(point.x >= rect.right-5)
            {
                return HTRIGHT;
            }
            else if(point.y <= rect.top+5)
            {    
                return HTTOP;
            }
            else if(point.y >= rect.bottom-5)
            {
                return HTBOTTOM;
            }
            else if(point.x <= rect.left+10 && point.y <= rect.top+10)
            {
                return HTTOPLEFT;
            }
            else if(point.x >= rect.right-10 && point.y <= rect.top+10)
            {
                return HTTOPRIGHT;
            }
            else if(point.x <= rect.left+10 && point.y >= rect.bottom-10)
            {
                return HTBOTTOMLEFT;
            }
            else if(point.x >= rect.right-10 && point.y >= rect.bottom-10)
            {
                return HTBOTTOMRIGHT;
            }
            return ::DefWindowProc(hWnd, message, wParam, lParam);

        case WM_SETCURSOR:
            {
                UINT nHitTest = LOWORD(lParam);
                switch(nHitTest)
                {
                case HTTOP:
                case HTBOTTOM:
                    SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENS)));
                    break;
                case HTLEFT:
                case HTRIGHT:
                    SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZEWE)));
                    break;
                case HTTOPLEFT:
                case HTBOTTOMRIGHT:
                    SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENWSE)));
                    break;
                case HTTOPRIGHT:
                case HTBOTTOMLEFT:
                    SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENESW)));
                    break;
                case HTCAPTION:
                case HTSYSMENU:
                case HTMENU:
                case HTCLIENT:
                default:
                    SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW)));
                    break;
                }
            }
            return TRUE;

        case WM_NCLBUTTONDOWN:
            switch(wParam)
            {
            case HTTOP:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_TOP, lParam);
                break;
            case HTBOTTOM:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOM, lParam);
                break;
            case HTLEFT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_LEFT, lParam);
                break;
            case HTRIGHT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_RIGHT, lParam);
                break;
            case HTTOPLEFT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPLEFT, lParam);
                break;
            case HTTOPRIGHT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_TOPRIGHT, lParam);
                break;
            case HTBOTTOMLEFT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMLEFT, lParam);
                break;
            case HTBOTTOMRIGHT:
                SendMessage(hWnd, WM_SYSCOMMAND, SC_SIZE | WMSZ_BOTTOMRIGHT, lParam);
                break;
            default:
                break;
            }
            return DefWindowProc(hWnd, message, wParam, lParam);

版本2.0（修正版本1.0的问题）

	switch (message)
	{	
	case WM_NCHITTEST:
		POINT point;
		point.x = LOWORD(lParam);
		point.y = HIWORD(lParam);
		RECT rect;        
		GetWindowRect(&rect);
		if(point.x <= rect.left+5)
		{
			return HTLEFT;
		}
		else if(point.x >= rect.right-5 && point.y < rect.bottom-10)
		{
			return HTRIGHT;
		}
		else if(point.y <= rect.top+5)
		{    
			return HTTOP;
		}
		else if(point.y >= rect.bottom-5&& point.x < rect.right-10)
		{
			return HTBOTTOM;
		}
		else if(point.x <= rect.left+10 && point.y <= rect.top+10)
		{
			return HTTOPLEFT;
		}
		else if(point.x >= rect.right-10 && point.y <= rect.top+10)
		{
			return HTTOPRIGHT;
		}
		else if(point.x <= rect.left+10 && point.y >= rect.bottom-10)
		{
			return HTBOTTOMLEFT;
		}
		else if(point.x >= rect.right-10 && point.y >= rect.bottom-10)
		{
			return HTBOTTOMRIGHT;
		}

	case WM_SETCURSOR:
		{
			UINT nHitTest = LOWORD(lParam);
			switch(nHitTest)
			{
			case HTTOP:
			case HTBOTTOM:
				SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENS)));
				break;
			case HTLEFT:
			case HTRIGHT:
				SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZEWE)));
				break;
			case HTTOPLEFT:
			case HTBOTTOMRIGHT:
				SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENWSE)));
				break;
			case HTTOPRIGHT:
			case HTBOTTOMLEFT:
				SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_SIZENESW)));
				break;
			case HTCAPTION:
			case HTSYSMENU:
			case HTMENU:
			case HTCLIENT:
			default:
				SetCursor(LoadCursor(NULL, MAKEINTRESOURCE(IDC_ARROW)));
				break;
			}
		}
		return TRUE;