串聯兩個BSTR的最佳方式是什麼？

Question

我試過幾種不同的方式來連接兩個BSTR，還沒有找到gopd的方式。我根本沒有在網上找到任何東西。

Answer 1

您應該使用像ATL CComBSTR這樣的包裝器，它也爲您處理資源管理。

沒有你有一個包裝做的：

BSTR Concat(BSTR a, BSTR b) 
{ 
    auto lengthA = SysStringLen(a); 
    auto lengthB = SysStringLen(b); 

    auto result = SysAllocStringLen(NULL, lengthA + lengthB); 

    memcpy(result, a, lengthA * sizeof(OLECHAR)); 
    memcpy(result + lengthA, b, lengthB * sizeof(OLECHAR)); 

    result[lengthA + lengthB] = 0; 
    return result; 
} 

int main() 
{ 
    auto a = SysAllocString(L"AAA"); 
    auto b = SysAllocString(L"BBB"); 
    auto c = Concat(a, b); 
    std::wcout << a << " + " << b << " = " << c << "\n"; 

    SysFreeString(a); 
    SysFreeString(b); 
    SysFreeString(c); 
} 

Answer 2

可以使用_bstr_t包裝：

#include <comutil.h> 

#pragma comment(lib, "comsupp.lib") 

// you have two BSTR's ... 
BSTR pOne = SysAllocString(L"This is a "); 
BSTR pTwo = SysAllocString(L"long string"); 

// you can wrap with _bstr_t 
_bstr_t pWrapOne = pOne; 
_bstr_t pWrapTwo = pTwo; 

// then just concatenate like this 
_bstr_t pConcat = pWrapOne + pWrapTwo;