Comment : effectuer une conversion entre différents types de chaînes

Mise à jour : novembre 2007

Cette rubrique explique comment convertir divers types de chaînes Visual C++ en d'autres chaînes. Les types de chaînes traités sont : char *, wchar_t*, _bstr_t, CComBSTR, CString, basic_string et System.String. Dans tous les cas, une copie de la chaîne est effectuée lors de la conversion vers le nouveau type. Toute modification apportée à la nouvelle chaîne n'affecte pas la chaîne d'origine, et inversement.

Exemple

Description

Cet exemple montre comment convertir un type char * en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (_bstr_t)
Hello, World! (CComBSTR)
Hello, World! (CString)
Hello, World! (basic_string)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type wchar_t * en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (wchar_t *)
Hello, World! (char *)
Hello, World! (_bstr_t)
Hello, World! (CComBSTR)
Hello, World! (CString)
Hello, World! (basic_string)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type _bstr_t en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (_bstr_t)
Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (CComBSTR)
Hello, World! (CString)
Hello, World! (basic_string)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type CComBSTR en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (CComBSTR)
Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (_bstr_t)
Hello, World! (CString)
Hello, World! (basic_string)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type CString en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (CString)
Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (_bstr_t)
Hello, World! (CComBSTR)
Hello, World! (basic_string)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type basic_string en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (basic_string)
Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (_bstr_t)
Hello, World! (CComBSTR)
Hello, World! (CString)
Hello, World! (System::String)

Exemple

Description

Cet exemple montre comment convertir un type System.String en un autre type de chaîne parmi ceux qui sont répertoriés ci-dessus.

Code

// 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;
}

Sortie

Hello, World! (System::String)
Hello, World! (char *)
Hello, World! (wchar_t *)
Hello, World! (_bstr_t)
Hello, World! (CComBSTR)
Hello, World! (CString)
Hello, World! (basic_string)

Voir aussi

Tâches

Visite guidée de Visual C++

Comment : convertir une chaîne standard en System::String

Comment : convertir System::String en chaîne standard

Comment : convertir System::String en wchar_t * ou char*

Concepts

ATL and MFC String Conversion Macros

CString Operations Relating to C-Style Strings

Programming with CComBSTR

Référence

mbstowcs_s, _mbstowcs_s_l

wcstombs_s, _wcstombs_s_l

strcpy_s, wcscpy_s, _mbscpy_s

strcat_s, wcscat_s, _mbscat_s

pin_ptr