做完棋盘之后却无法完成左键点击棋盘，而切换棋盘BMP图片

Posted 2020-07-23 养老保险年审

做完棋盘之后却无法完成左键点击棋盘，而切换棋盘BMP图片

解决办法：

目前推测可能是因为HDC的原因造成无法切换，HDC只能在WM_PAINT消息中使用，其它消息中使用都不会被执行。

有了原因就想出对策，把需要HDC的函数全部放在WM_PAINT消息中去处理，这样就可以共用WM_PAINT中的HDC了

代码：

HINSTANCE g_hInst = NULL;
HANDLE g_hStdout = NULL; //控制台
CHAR szText[256] = { 0 }; //调试用
#define PrintLog(x) 	WriteConsole(g_hStdout, x, strlen(x), 0, 0);
int i = 1;
//获得坐标
int xPos = 0;
int yPos = 0;
void DrawBk(HDC hDC)
{
	int marc = 0; //控制棋盘所在位置
	for (int i = 0; i < 10; i++) //画九格横线
	{
		MoveToEx(hDC, marc + 50, marc + 50 + i * 48, NULL);
		LineTo(hDC, marc + 480, marc + 50 + i * 48);
	}
	for (int j = 0; j < 10; j++) //画九格直线
	{
		MoveToEx(hDC, marc + 50 + j * 48, marc + 50, NULL);
		LineTo(hDC, marc + 50 + j * 48, marc + 480);
	}
	//背景图处理
	HBITMAP hBitMap = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_BKMP1));
	HDC hBmap = CreateCompatibleDC(hDC);
	HGDIOBJ hOldBmp = SelectObject(hBmap, hBitMap);
	//绘图开始
	for (int i = 0; i < 9; i++)
	{
		for (int j = 0; j < 9; j++)
		{
			BitBlt(hDC, 50 + j * 48, 50 + i * 48, 48, 48, hBmap, 0, 0, MERGECOPY);
		}
	}
	SelectObject(hDC, hOldBmp);
	DeleteDC(hBmap);
	DeleteObject(hBitMap);
}
void OnLButton(HDC hDC)
{
	//PAINTSTRUCT ps = { 0 };
	//HDC hDC = BeginPaint(hWnd, &ps);
	int marc = 0; //控制棋盘所在位置
	if (xPos>50 && yPos >50)
	{
		//背景图处理
		HBITMAP hBitMap = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_BKMP2));
		HDC hBmap = CreateCompatibleDC(hDC);
		HGDIOBJ hOldBmp = SelectObject(hBmap, hBitMap);
		//绘图开始
		int xPoint = (xPos - 50) / 48;
		int yPoint = (yPos - 50) / 48;
		sprintf_s(szText, 256, "OnLButton,x=%d,y=%d\n", xPoint, yPoint);
		PrintLog(szText);
		BitBlt(hDC, 50 + xPoint * 48, 50 + yPoint * 48, 48, 48, hBmap, 0, 0, SRCCOPY);
		SelectObject(hDC, hOldBmp);
		DeleteDC(hBmap);
		DeleteObject(hBitMap);
	}
}
//OnPaint
void OnPaint(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)
{
	PAINTSTRUCT ps = { 0 };
	HDC hDC = BeginPaint(hWnd, &ps);
	
	if (i == 1) //暂时屏蔽棋盘每次刷新的办法，后面可以用控件解决
	{
		DrawBk(hDC);
		i = 2;
	}
	OnLButton(hDC);
	EndPaint(hWnd, &ps);
}

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