VC6.0下MFC的双缓存颜色显示问题

参考了多个网上的有关双缓存的资料，都只是讲简单的怎样实现双缓存，而我在MFC的对话中调用了SelectObject等方法来重置不同颜色的画笔和画刷，而且设置多次，查来查去找不到解决的办法，后来看了CSDN的相关文档才解决了。
以下是相关的原文解读：（CreateCompatibleBitmap方法，注意是Windows GDI: Platform SDK中的）

Note: When a memory device context is created, it initially has a 1-by-1 monochrome bitmap selected into it. If this memory device context is used in CreateCompatibleBitmap, the bitmap that is created is a monochrome bitmap. To create a color bitmap, use the hDC that was used to create the memory device context, as shown in the following code:

HDC memDC = CreateCompatibleDC ( hDC ); HBITMAP memBM = CreateCompatibleBitmap ( hDC ); SelectObject ( memDC, memBM );

 

If an application sets the nWidth or nHeight parameters to zero, CreateCompatibleBitmap returns the handle to a 1-by-1 pixel, monochrome bitmap.

看来要存放的缓存格式（样式）要和原来的客户区一致就可以实现非黑白单色的彩色了，顺便给出自己的部分代码：

 

CDC* pdc = (CPaintDC*)GetDC();CRect clientRect;GetClientRect(&clientRect);CDC memdc;CBitmap MemBitmap;//注意下面的CreateCompatibleDC函数调用的参数用的是pdc，不是NULLmemdc.CreateCompatibleDC(pdc);//注意下面的CreateCompatibleBitmap函数调用的第一个参数用的是pdc，不是&memdcMemBitmap.CreateCompatibleBitmap(pdc,clientRect.Width(),clientRect.Height());CBitmap *pOldBit=memdc.SelectObject(&MemBitmap);static CPen GreenPen(PS_SOLID, 5, RGB(0, 255, 0));static CPen BlackPen(PS_SOLID, 1, RGB(0, 0, 0));static CPen SapGreenPen(PS_SOLID, 1, RGB(46, 139, 87));static CPen* OldPen;static CBrush BlackBrush(RGB(0, 0, 0));static CBrush* OldBrush;//画一个黑色的矩形OldPen = (CPen*)memdc.SelectObject(&BlackPen);OldBrush = (CBrush*)memdc.SelectObject(&BlackBrush);CRect cr(0, 0, 500, 200);memdc.Rectangle(cr);memdc.SelectObject(&SapGreenPen);//画暗绿色的图吧，详细代码不给出了memdc.SelectObject(&GreenPen);//画绿色的图吧，详细代码不给出了pdc->BitBlt(0,0,clientRect.Width(),clientRect.Height(),&memdc,0,0,SRCCOPY);memdc.SelectObject(OldPen);memdc.SelectObject(OldBrush);memdc.SelectObject(pOldBit);memdc.DeleteDC();MemBitmap.DeleteObject();