CMapStringToPtr添加与释放

头文件.h

//--------------------------------------------------------------------
	CMapStringToPtr m_prjFiles;
	CStringList m_fileList;
	CStringList m_nameList;

	typedef struct 
	{
		CString strPath;
		CString strName;
	}ST_LINE_INFO;

源文件.cpp

1、插入元素

// 添加元素
	m_fileList.AddTail(_T("C:\\a"));
	m_fileList.AddTail(_T("C:\\b"));
	m_fileList.AddTail(_T("C:\\c"));

	m_nameList.AddTail(_T("testA"));
	m_nameList.AddTail(_T("testB"));
	m_nameList.AddTail(_T("testC"));

	//遍历CStringList变量,添加到CMapStringToPtr
	for (POSITION pos = m_fileList.GetHeadPosition(), pos1 = m_nameList.GetHeadPosition(); pos&&pos1; m_fileList.GetNext(pos), m_nameList.GetNext(pos1))
	{
		ST_LINE_INFO* fi = new ST_LINE_INFO; //一个自定义结构体
		fi->strName = m_nameList.GetAt(pos1);
		fi->strPath = m_fileList.GetAt(pos);

		void* pVoid = NULL;
		// BOOL CMapStringToPtr::LookUp(void*<key>,void*&<rvalue>)
		// 返回CString值为key的空指针
		if (m_prjFiles.Lookup(fi->strName, pVoid))
		{
			//查找元素
			delete fi;
			fi = NULL;
		}
		else
		{
			//往map添加元素
			m_prjFiles.SetAt(fi->strName, fi);
		}
	}

2、打印map元素信息按钮

//打印
void CMapStrToPtrDlg::OnBnClickedButton1()
{
	// TODO: Add your control notification handler code here
	//遍历链表
	POSITION pos = m_prjFiles.GetStartPosition(); //返回第一个元素的位置
	CString info = _T("");
	while (pos)
	{
		CString fileName;
		ST_LINE_INFO* fi = NULL;
		//void* rval = NULL;
		m_prjFiles.GetNextAssoc(pos, fileName, (void*&)fi); //pos++,获取的是堆上是地址
		if (fi)
		{
			OutputDebugString(fileName+_T("\n"));
			OutputDebugString(fi->strPath+_T("\n"));
			info += (fileName + _T("\n") + fi->strPath + _T("\n"));
			fi = NULL; //使指针变量重新指向,但堆中地址仍在那里
		}
	}
	MessageBox(info);
	/*
	testC
	C:\c
	testB
	C:\b
	testA
	C:\a
	*/

}

3、删除map元素按钮

//删除
void CMapStrToPtrDlg::OnBnClickedButton2()
{
	// TODO: Add your control notification handler code here
	for (POSITION pos = m_prjFiles.GetStartPosition(); pos;){
		CString strKey;
		ST_LINE_INFO* val = NULL;  // 注意这里必须是添加时的变量类型，如果用void*，则会有内存泄露。
		m_prjFiles.GetNextAssoc(pos, strKey, (void*&)val);    // 这里把定义的变量类型转换为void*&。pos++
		if (val)
		{
			delete val; //删除指针变量指向的堆中地址内容
			val = NULL; //指针变量重新指向
		}
	}
	m_prjFiles.RemoveAll();
	MessageBox(_T("删除成功!"));
}