Question

目前我想在C ++ Buillder XE2中使用TDitionary

在我阅读documentation后，我认为应该很容易，但我甚至无法创建TDictionary对象......

我的代码：

#include <vcl.h>
#pragma hdrstop
#include <Generics.collections.hpp>
#include "TDictionaryTest.h"

#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;

void __fastcall TForm2::FormCreate(TObject *Sender)
{
    TDictionary__2 <String, String> *Dir = new  TDictionary__2<String, String>(0);
    delete Dir;
}

错误讯息：

[ILINK32 Error] Error: Unresolved external '__fastcall           System::Generics::Collections::TDictionary__2<System::UnicodeString,   System::UnicodeString>::~TDictionary__2<System::UnicodeString, System::UnicodeString>()'  referenced from ...\PRACTICE\C++\WIN32\DEBUG\TDICTIONARYTEST.OBJ
[ILINK32 Error] Error: Unresolved external '__fastcall System::Generics::Collections::TEnumerable__1<System::Generics::Collections::TPair__2<System::UnicodeString, System::UnicodeString> >::~TEnumerable__1<System::Generics::Collections::TPair__2<System::UnicodeString, System::UnicodeString> >()' referenced from ...\PRACTICE\C++\WIN32\DEBUG\TDICTIONARYTEST.OBJ
[ILINK32 Error] Error: Unresolved external 'System::Generics::Collections::TDictionary__2<System::UnicodeString, System::UnicodeString>::' referenced from ...\PRACTICE\C++\WIN32\DEBUG\TDICTIONARYTEST.OBJ
[ILINK32 Error] Error: Unresolved external '__fastcall System::Generics::Collections::TDictionary__2<System::UnicodeString, System::UnicodeString>::TDictionary__2<System::UnicodeString, System::UnicodeString>(int)' referenced from ...\PRACTICE\C++\WIN32\DEBUG\TDICTIONARYTEST.OBJ
[ILINK32 Error] Error: Unable to perform link

任何人都有任何想法？谢谢！

Answer 1

就像@mhtaqia所说的那样，C ++还不能实例化Delphi的Generics类，只有在用Delphi代码创建它们时才会使用它们。对于C ++代码，您应该使用STL std::map代替：

#include <map> 

void __fastcall TForm2::FormCreate(TObject *Sender) 
{ 
    std::map<String, String> *Dir = new std::map<String, String>; 
    delete Dir; 
}

或者：

#include <map> 

void __fastcall TForm2::FormCreate(TObject *Sender) 
{ 
    std::map<String, String> Dir; 
}

旁注：不要曾在C ++中使用TForm::OnCreate和TForm::OnDestroy事件。它们是Delphi习惯用法，可以在C ++中产生非法行为，因为它们可以分别在派生构造函数和派生析构函数之后触发。改为使用实际的构造函数/析构函数。

Answer 2

TDictionary仅用于访问Delphi变量和字段。您不能在C ++代码中使用和实例化它。模板类在头文件中完全定义时可用。

在C ++ Builder XE2中使用TDictionary

2 个答案: