如何：在各种字符串类型之间进行转换（zz）

 

zz from：http://msdn.microsoft.com/zh-cn/library/ms235631(VS.80).aspx

本主题演示如何将各种 Visual C++ 字符串类型转换为其他字符串。可以转换的字符串类型包括 char *、wchar_t*、_bstr_t、CComBSTR、CString、basic_string 和 System.String。在所有情况下，在将字符串转换为新类型时，都会创建字符串的副本。对新字符串进行的任何更改都不会影响原始字符串，反之亦然。

 

 

1. 从 char * 转换

// convert_from_char.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){ char *orig = "Hello, World!"; cout << orig << " (char *)" << endl; // Convert to a wchar_t* size_t origsize = strlen(orig) + 1; const size_t newsize = 100; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig, _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl; // Convert to a basic_string string basicstring(orig); basicstring += " (basic_string)"; cout << basicstring << endl; // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

2. 从 wchar_t * 转换

// convert_from_wchar_t.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){ wchar_t *orig = L"Hello, World!"; wcout << orig << L" (wchar_t *)" << endl; // Convert to a char* size_t origsize = wcslen(orig) + 1; const size_t newsize = 100; size_t convertedChars = 0; char nstring[newsize]; wcstombs_s(&convertedChars, nstring, origsize, orig, _TRUNCATE); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl; // Convert to a basic_string wstring basicstring(orig); basicstring += L" (basic_string)"; wcout << basicstring << endl; // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

3. 从 _bstr_t 转换

// convert_from_bstr_t.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){ _bstr_t orig("Hello, World!"); wcout << orig << " (_bstr_t)" << endl; // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, (char *)orig); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, (wchar_t *)orig); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a CComBSTR CComBSTR ccombstr((char *)orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a CString CString cstring((char *)orig); cstring += " (CString)"; cout << cstring << endl; // Convert to a basic_string string basicstring((char *)orig); basicstring += " (basic_string)"; cout << basicstring << endl; // Convert to a System::String String ^systemstring = gcnew String((char *)orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

4. 从 CComBSTR 转换

// convert_from_ccombstr.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"using namespace std;using namespace System;using namespace System::Runtime::InteropServices;int main(){ CComBSTR orig("Hello, World!"); CW2A printstr(orig); cout << printstr << " (CComBSTR)" << endl; // Convert to a char* const size_t newsize = 100; char nstring[newsize]; CW2A tmpstr1(orig); strcpy_s(nstring, tmpstr1); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, orig); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CString CString cstring(orig); cstring += " (CString)"; cout << cstring << endl; // Convert to a basic_string wstring basicstring(orig); basicstring += L" (basic_string)"; wcout << basicstring << endl; // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

5. 从CString转换

// convert_from_cstring.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){ CString orig("Hello, World!"); wcout << orig << " (CString)" << endl; // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, orig); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a wchar_t* // You must first convert to a char * for this to work. size_t origsize = strlen(orig) + 1; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig, _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a _bstr_t _bstr_t bstrt(orig); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CComBSTR CComBSTR ccombstr(orig); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a basic_string string basicstring(orig); basicstring += " (basic_string)"; cout << basicstring << endl; // Convert to a System::String String ^systemstring = gcnew String(orig); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

6. 从 basic_string 转换

// convert_from_basic_string.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"using namespace std;using namespace System;int main(){ string orig("Hello, World!"); cout << orig << " (basic_string)" << endl; // Convert to a char* const size_t newsize = 100; char nstring[newsize]; strcpy_s(nstring, orig.c_str()); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a wchar_t* // You must first convert to a char * for this to work. size_t origsize = strlen(orig.c_str()) + 1; size_t convertedChars = 0; wchar_t wcstring[newsize]; mbstowcs_s(&convertedChars, wcstring, origsize, orig.c_str(), _TRUNCATE); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a _bstr_t _bstr_t bstrt(orig.c_str()); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CComBSTR CComBSTR ccombstr(orig.c_str()); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a CString CString cstring(orig.c_str()); cstring += " (CString)"; cout << cstring << endl; // Convert to a System::String String ^systemstring = gcnew String(orig.c_str()); systemstring += " (System::String)"; Console::WriteLine("{0}", systemstring); delete systemstring;} 

 

7. 从 System::String 转换

// convert_from_system_string.cpp// compile with: /clr /link comsuppw.lib#include <iostream>#include <stdlib.h>#include <string>#include "atlbase.h"#include "atlstr.h"#include "comutil.h"#include "vcclr.h"using namespace std;using namespace System;using namespace System::Runtime::InteropServices;int main(){ String ^orig = gcnew String("Hello, World!"); Console::WriteLine("{0} (System::String)", orig); pin_ptr<const wchar_t> wch = PtrToStringChars(orig); // Convert to a char* size_t origsize = wcslen(wch) + 1; const size_t newsize = 100; size_t convertedChars = 0; char nstring[newsize]; wcstombs_s(&convertedChars, nstring, origsize, wch, _TRUNCATE); strcat_s(nstring, " (char *)"); cout << nstring << endl; // Convert to a wchar_t* wchar_t wcstring[newsize]; wcscpy_s(wcstring, wch); wcscat_s(wcstring, L" (wchar_t *)"); wcout << wcstring << endl; // Convert to a _bstr_t _bstr_t bstrt(wch); bstrt += " (_bstr_t)"; cout << bstrt << endl; // Convert to a CComBSTR CComBSTR ccombstr(wch); if (ccombstr.Append(L" (CComBSTR)") == S_OK) { CW2A printstr(ccombstr); cout << printstr << endl; } // Convert to a CString CString cstring(wch); cstring += " (CString)"; cout << cstring << endl; // Convert to a basic_string wstring basicstring(wch); basicstring += L" (basic_string)"; wcout << basicstring << endl; delete orig;}