RegisterShellFileTypes();//注册自定义文件类型，双击可直接打开

示例:

新建单文档MFC程序；

添加菜单：

修改字符串表：

ctrl+w 添加消息映射：

在视图类中，加菜单按钮的COMMAND和UPDATE_COMMAND_UI事件，然后视图类添加 WM_LBUTTONDOWN、WM_LBUTTONUP 、M_MOUSEMOVE消息事件。

主要核心代码：

//view的头文件中添加 成员变量和函数声明
public:
	CMFCdraw2Doc* GetDocument();
	CPoint m_ptBegin;//起点坐标
	CPoint m_ptEnd;//终点坐标
	UINT m_nType;//类型：1-直线，2-距形，3-圆
	BOOL m_bFlag;//是否开始画线
	void DrawShape(CDC *pDC, CPoint p1, CPoint p2);



// CMFCdraw2View construction/destruction
CMFCdraw2View::CMFCdraw2View()
{
	// TODO: add construction code here
	m_nType=0;
	m_bFlag=FALSE;
	m_ptBegin=m_ptEnd=0;
}
// CMFCdraw2View drawing

void CMFCdraw2View::OnDraw(CDC* pDC)
{
	CMFCdraw2Doc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	CBrush *pOldBrush=(CBrush *)
		pDC->SelectStockObject(NULL_BRUSH);

	for(int i=0;i<pDoc->m_arrShapes.GetSize();i++)
	{
		CShape *pshape=(CShape*)pDoc->m_arrShapes[i];
		switch(pshape->m_nType)
		{
		case 1:
			pDC->MoveTo(pshape->m_ptBegin);
			pDC->LineTo(pshape->m_ptEnd);
			break;
		case 2:
			pDC->Rectangle(pshape->m_ptBegin.x,pshape->m_ptBegin.y,
				pshape->m_ptEnd.x,pshape->m_ptEnd.y);
			break;
		case 3:
			pDC->Ellipse(pshape->m_ptBegin.x,pshape->m_ptBegin.y,
				pshape->m_ptEnd.x,pshape->m_ptEnd.y);
			break;
		}
	}
	pDC->SelectObject(pOldBrush);


	// TODO: add draw code for native data here
}

void CMFCdraw2View::OnDrawElipse() 
{
	// TODO: Add your command handler code here
	m_nType=3;
}

void CMFCdraw2View::OnDrawLine() 
{
	// TODO: Add your command handler code here
	m_nType=1;
}

void CMFCdraw2View::OnDrawRect() 
{
	// TODO: Add your command handler code here
	m_nType=2;
}

void CMFCdraw2View::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	// TODO: Add your message handler code here and/or call default
	m_bFlag=TRUE;//开始绘图
    m_ptBegin=m_ptEnd=point; //确定起点位置 
	CView::OnLButtonDown(nFlags,point);
}


void CMFCdraw2View::OnLButtonUp(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	m_bFlag=FALSE;//结束画线
	CShape * pshape=new CShape;
	pshape->m_ptBegin=m_ptBegin;
	pshape->m_ptEnd=m_ptEnd;
	pshape->m_nType=m_nType;
	CMFCdraw2Doc *pDoc=(CMFCdraw2Doc*)GetDocument();
	pDoc->m_arrShapes.Add(pshape);//保存到文档的图形集合中
	CView::OnLButtonUp(nFlags, point);
}

void CMFCdraw2View::OnMouseMove(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	CClientDC dc(this);
	if(m_bFlag)
	{
		//擦线
		DrawShape(&dc,m_ptBegin,m_ptEnd);
		//画线
		DrawShape(&dc,m_ptBegin,point);
		//保存终点位置，为擦线准备
		m_ptEnd=point;
    }
	CView::OnMouseMove(nFlags, point);
}
void CMFCdraw2View::DrawShape(CDC *pDC, CPoint p1, CPoint p2)
{
	//设置绘图模式，R2_NOT与当前画线处颜色相反
	pDC->SetROP2(R2_NOT);
	//设置画刷为透明画刷
	CBrush *pOldBrush=
		(CBrush*)pDC->SelectStockObject(NULL_BRUSH);
	switch (m_nType)
	{
	case 1://直线
		pDC->MoveTo(p1);
		pDC->LineTo(p2);
		break;
	case 2://矩形
		pDC->Rectangle(p1.x,p1.y,p2.x,p2.y);
		break;
	case 3://椭圆
		pDC->Ellipse(p1.x,p1.y,p2.x,p2.y);
		break;
	}
	//恢复默认画刷
	pDC->SelectObject(pOldBrush);
	
}

void CMFCdraw2View::OnUpdateDrawElipse(CCmdUI* pCmdUI) 
{
	// TODO: Add your command update UI handler code here
	pCmdUI->SetRadio(m_nType==3);//更改选中的状态
}

void CMFCdraw2View::OnUpdateDrawLine(CCmdUI* pCmdUI) 
{
	// TODO: Add your command update UI handler code here
	pCmdUI->SetRadio(m_nType==1);
}

void CMFCdraw2View::OnUpdateDrawRect(CCmdUI* pCmdUI) 
{
	// TODO: Add your command update UI handler code here
	pCmdUI->SetRadio(m_nType==2);
}



//doc头文件添加成员变量和函数声明
public:
	CObArray m_arrShapes;
	UINT m_nShapeCount;//图形数量
	void releaseShapes();

//Doc类cpp中
CMFCdraw2Doc::CMFCdraw2Doc()
{
	// TODO: add one-time construction code here
	releaseShapes();
}

CMFCdraw2Doc::~CMFCdraw2Doc()
{
	releaseShapes();
}

BOOL CMFCdraw2Doc::OnNewDocument()
{
	if (!CDocument::OnNewDocument())
		return FALSE;
	releaseShapes();
	// TODO: add reinitialization code here
	// (SDI documents will reuse this document)

	return TRUE;
}



/////////////////////////////////////////////////////////////////////////////
// CMFCdraw2Doc serialization

void CMFCdraw2Doc::Serialize(CArchive& ar)
{
	if (ar.IsStoring())
	{
		//存储图形数据前，先存储图形数量
		ar<<m_arrShapes.GetSize();
		for (int i=0;i<m_arrShapes.GetSize();i++)
		{
			CShape *pShape=(CShape *)m_arrShapes[i];
			ar<<pShape;
		}
		
	}
	else
	{
		//读取时，先要读取图形数量
		ar>>m_nShapeCount;
		for (int i=0;i<m_nShapeCount;i++)
		{
			CShape *pShape=NULL;
			ar>>pShape;
			m_arrShapes.Add(pShape);
			
		}
	}
}




/////////////////////////////////////////////////////////////////////////////
// CMFCdraw2Doc commands

void CMFCdraw2Doc::releaseShapes()
{
	for (int i=0;i<m_arrShapes.GetSize();i++)
	{
		delete m_arrShapes[i];
	}
    m_arrShapes.RemoveAll();
}


// Shape.h: interface for the CShape class.
//
//////////////////////////////////////////////////////////////////////

#if !defined(CSHAPE_H)
#define CSHAPE_H

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
//记录一个形状的类
class CShape : public CObject  
{
public:
	CShape();
	virtual ~CShape();
	virtual void Serialize( CArchive& ar );//序列化用的虚函数
public:
	CPoint m_ptBegin;//起点
	CPoint m_ptEnd;//终点
	UINT m_nType;//图形类型
	DECLARE_SERIAL(CShape)
};

#endif // !defined(CSHAPE_H)


//CShape.cpp
#include "stdafx.h"
#include "MFCdraw2.h"
#include "CShape.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
IMPLEMENT_SERIAL(CShape,CObject,1)
CShape::CShape()
{
	m_ptBegin=m_ptEnd=0;
	m_nType=1;//直线
}

CShape::~CShape()
{
	
}
void CShape::Serialize( CArchive& ar )
{
	CObject::Serialize(ar);
	if (ar.IsStoring())
	{
		ar<<m_ptBegin<<m_ptEnd<<m_nType;
	}
	else
	{
		ar>>m_ptBegin>>m_ptEnd>>m_nType;
	}
}

      的单击位置，判断单元格，然后使用当前颜色填充该单元格

【示例稍后补充】