C++ MFC容器列表的STL迭代器
我有一个文件夹类,它包含两个文件夹和文件列表 列表源于CObList<代码>类容器:公共CObList。我需要在foldersInFolder中按名称执行搜索,在FileInfolder中按名称和扩展名执行搜索。CObList::Find不允许我使用谓词。我通常将std::find_与谓词一起使用:C++ MFC容器列表的STL迭代器,c++,stl,mfc,iterator,function-pointers,C++,Stl,Mfc,Iterator,Function Pointers,我有一个文件夹类,它包含两个文件夹和文件列表 列表源于CObList类容器:公共CObList。我需要在foldersInFolder中按名称执行搜索,在FileInfolder中按名称和扩展名执行搜索。CObList::Find不允许我使用谓词。我通常将std::find_与谓词一起使用: struct Comparator { Folder::StringT stringToCompare; bool operator() ( const Folder* lhs )
struct Comparator
{
Folder::StringT stringToCompare;
bool operator() ( const Folder* lhs )
{
return lhs->GetFolderName( ) == stringToCompare;
}
};
所以我需要一个迭代器来使用这个函数。在[codeguru]上,他们定义了一个类basemCiter][1],它是std::iterator的子类:
#include < iterator >
// Define BaseMFCIter as a standard input iterator.
//
// The template arguments are:
// Item: the contained element type
// Cont: the container type
// Key: the access key (defaults to POSITION)
template < class Item, class Cont, class Key = POSITION >
class BaseMFCIter : public std::iterator < std::input_iterator_tag, Item >
{
public:
// Define types for the 2 member functions to be used:
typedef Key (Cont::*GetFirstFunctionPtr) () const;
typedef Item (Cont::*GetNextFunctionPtr) (Key&) const;
// Default constructor, makes a null iterator, equal to BaseMFCIter::end()
BaseMFCIter() : m_pCont(0), m_Pos(0), m_GetFirstFunc(0), m_GetNextFunc(0), m_End(true) {}
// Constructor taking pointer to container and the iteration functions
BaseMFCIter(Cont* pCont, GetFirstFunctionPtr pFF, GetNextFunctionPtr pNF)
: m_pCont(pCont), m_Pos(0), m_GetFirstFunc(pFF), m_GetNextFunc(pNF)
{ init(); }
// Copy constructor, initialises iterator to first element
BaseMFCIter(const BaseMFCIter& vi) : m_pCont(vi.m_pCont), m_Pos(0),
m_GetFirstFunc(vi.m_GetFirstFunc), m_GetNextFunc(vi.m_GetNextFunc)
{ init(); }
// Assignment operator, initialises iterator to first element
BaseMFCIter& operator=(const BaseMFCIter& vi)
{
m_pCont = vi.m_pCont;
m_GetFirstFunc = vi.m_GetFirstFunc;
m_GetNextFunc = vi.m_GetNextFunc;
init();
return *this;
}
bool operator == (const BaseMFCIter& rhs) const
{ return (m_Pos == rhs.m_Pos && m_End == rhs.m_End); }
bool operator != (const BaseMFCIter& rhs) const
{ return !operator==(rhs); }
BaseMFCIter& operator ++ () { advance(); return *this; }
BaseMFCIter& operator ++ (int) { BaseMFCIter ret(*this); advance(); return ret; }
Item operator * () { return m_Item; }
Item operator -> () { return m_Item; }
static BaseMFCIter end () { return BaseMFCIter(); } // end() returns default null iterator
private:
Item m_Item; // Current item from container
Cont* m_pCont; // Pointer to container
Key m_Pos; // Key to item in container
bool m_End; // Flag to indicate end of container reached
// Pointers to container iteration functions
GetFirstFunctionPtr m_GetFirstFunc;
GetNextFunctionPtr m_GetNextFunc;
// Use container GetFirst & GetNext functions to set to first element, or end() if not found
void init()
{
m_Pos = 0;
m_End = true;
if (m_pCont && m_GetFirstFunc != 0)
{
m_Pos = (m_pCont->*m_GetFirstFunc)();
advance();
}
}
// Use container GetNext function to find next element in container
void advance()
{
m_End = m_Pos ? false : true;
m_Item = (m_Pos && m_pCont && m_GetNextFunc != 0) ?
(m_pCont->*m_GetNextFunc)(m_Pos) : Item();
}
};
#包括
//将BaseMCiter定义为标准输入迭代器。
//
//模板参数包括:
//项:包含的元素类型
//Cont:容器类型
//键:访问键(默认为位置)
模板<类别项目,类别控制,类别键=位置>
类BaseMFCIter:public std::iterator
{
公众:
//定义要使用的2个成员函数的类型:
typedef键(Cont::*GetFirstFunctionPtr)()常量;
typedef项(续::*GetNextFunctionPtr)(键和)常量;
//默认构造函数,生成一个空迭代器,等于BaseMFCIter::end()
BaseMFCIter():m_pCont(0),m_Pos(0),m_GetFirstFunc(0),m_GetNextFunc(0),m_End(true){}
//使用指向容器和迭代函数的指针的构造函数
BaseMFCIter(续*pCont、GetFirstFunctionPtr pFF、GetNextFunctionPtr pNF)
:m_pCont(pCont)、m_Pos(0)、m_GetFirstFunc(pFF)、m_GetNextFunc(pNF)
{init();}
//复制构造函数,初始化迭代器到第一个元素
BaseMfcitter(const BaseMfcitter&vi):m_pCont(vi.m_pCont),m_Pos(0),
m_GetFirstFunc(vi.m_GetFirstFunc)、m_GetNextFunc(vi.m_GetNextFunc)
{init();}
//赋值运算符,初始化迭代器到第一个元素
BaseMFCIter和运算符=(常量BaseMFCIter和vi)
{
m_pCont=vi.m_pCont;
m_GetFirstFunc=vi.m_GetFirstFunc;
m_GetNextFunc=vi.m_GetNextFunc;
init();
归还*这个;
}
布尔运算符==(常量BaseMFCIter和rhs)常量
{return(m_Pos==rhs.m_Pos&&m_End==rhs.m_End)}
布尔运算符!=(常量BaseMFCIter和rhs)常量
{return!运算符==(rhs);}
BaseMFCIter&operator++(){advance();返回*this;}
BaseMFCIter&operator++(int){BaseMFCIter-ret(*this);advance();return-ret;}
项运算符*(){return m_Item;}
项运算符->(){return m_Item;}
静态BaseMFCIter end(){return BaseMFCIter();}//end()返回默认的空迭代器
私人:
Item m_Item;//容器中的当前项
Cont*m_pCont;//指向容器的指针
Key m_Pos;//容器中项目的键
bool m_End;//表示已到达容器末尾的标志
//指向容器迭代函数的指针
GetFirstFunction PTR m_GetFirstFunc;
GetNextFunction PTR m_GetNextFunc;
//使用容器GetFirst和GetNext函数设置为第一个元素,如果找不到,则设置为end()
void init()
{
m_Pos=0;
m_End=真;
if(m_pCont&&m_GetFirstFunc!=0)
{
m_Pos=(m_pCont->*m_GetFirstFunc)();
前进();
}
}
//使用container GetNext函数查找容器中的下一个元素
作废预付款()
{
m_End=m_Pos?false:true;
m_Item=(m_Pos和m_pCont和m_GetNextFunc!=0)?
(m_pCont->*m_GetNextFunc)(m_Pos):Item();
}
};
但如果我定义自己的ListItemer类,myObject是File或Folder
class ListIter : public BaseMFCIter < myCObject, CObList >
{
public:
ListIter( CObList* pObj = 0) : BaseMFCIter< myCObject, CObList >
(pObj, &CObList::GetHeadPosition, &CObList::GetNext )
{}
};
class列表项:public-basemCiter
{
公众:
ListIter(CObList*pObj=0):BaseMFCIter
(pObj,&CObList::GetHeadPosition,&CObList::GetNext)
{}
};
这会导致编译器错误:
Error 1 error C2664: 'BaseMFCIter<Item,Cont>::BaseMFCIter(Cont *,__POSITION (__thiscall CObList::* )(void) const,myCObject (__thiscall CObList::* )(Key &) const)' : cannot convert parameter 3 from 'overloaded-function' to 'myCObject (__thiscall CObList::* )(Key &) const'
Error 1 Error C2664:'BaseMFCIter::BaseMFCIter(Cont*,'u位置('u thiscall CObList::*)(void)const,myobject('u thiscall CObList::*)(Key&)const)':无法将参数3从“重载函数”转换为“myobject('u thiscall CObList::*)(Key&)const”
对于这个重载函数的问题,有解决方法吗?如果有类似于std::find_If的MFC集合,请告诉我 以下是一个基于您提供的测试源的完整工作修复的示例: 下载链接:
struct Container : public CObList
{
myCObject* GetNext(POSITION& rPosition)
{
return dynamic_cast<myCObject*>(CObList::GetNext(rPosition));
}
myCObject const* GetNext(POSITION& rPosition) const
{
return dynamic_cast<const myCObject*>(CObList::GetNext(rPosition));
}
};
class ListIter : public BaseMFCIter < const myCObject*, Container, POSITION >
{
public:
ListIter( Container* pObj = 0)
: BaseMFCIter< const myCObject*, Container, POSITION >
(pObj, &CObList::GetHeadPosition, &Container::GetNext)
{
}
};
void main( )
{
myCObject* m = new myCObject( 1 );
myCObject* n = new myCObject( 2 );
myCObject* p = new myCObject( 3 );
myCObject* q = new myCObject( 4 );
Container cont;
cont.AddHead( m );
cont.AddHead( n );
cont.AddHead( p );
cont.AddHead( q );
POSITION pos = cont.GetHeadPosition( );
while (pos != NULL)
{
const myCObject& item = *cont.GetNext( pos );
std::cout << "Oldfashioned: " << item.x << std::endl;
}
for (ListIter it=ListIter(&cont); it!= ListIter(); ++it)
{
std::cout << "Newfangled: " << it->x << std::endl;
}
}
如你所见,我
- 使用strong类型的访问器扩展了
派生类(todo:您可能需要添加其他容器
接口成员,例如CObList:*
)GetAt(…)
- 修复了来自的
模板的实例化BaseMFCIter
BaseMFCIter < myCObject, Container, POSITION >
到BaseMFCIter
BaseMFCIter
- 包括一个STL标准样式的循环到
,以演示它的工作原理main
Oldfashioned: 4
Oldfashioned: 3
Oldfashioned: 2
Oldfashioned: 1
Newfangled: 4
Newfangled: 3
Newfangled: 2
Newfangled: 1
BaseMFCIter < myCObject, Container, POSITION >
BaseMFCIter < const myCObject*, Container, POSITION >