如何将double转换为BSTR [英] How to convert double to BSTR

问题描述

想要为BSTR字符串分配一个双精度值.
此

Want to assign a double value to BSTR string.
Are there any macros /functions for this

推荐答案

是否有任何宏/函数，您可以代表一个带有BSTR的双精度值，例如

You may just represent a double value with a BSTR, for instance

#include <windows.h>
#include <tchar.h>
#include <sstream>
using namespace std;

int main()
{
  wostringstream wos;
  double d = 0.57;
  wos << d;
  BSTR bstr = SysAllocString(wos.str().c_str());
  // enjoy with bstr
  // ...
  SysFreeString(bstr);
}

#include "windows.h"
#include "comutil.h"

void your_func(BSTR bstr);

int main()
{
   _bstr_t str(_variant_t(double(123.456)));
   
   // str is castable to BSTR
   // use it like this

   your_func(str);

   // or simply
   your_func(_bstr_t(_variant_t(double(123.456))));
   
   return 0;
}

为什么不使用 VarBstrFromR8 [ ^ ] Windows API?

还有许多其他数据类型转换函数 [

Why not use VarBstrFromR8[^] Windows API?

There are many other Data Type Conversion Functions[^] provided with Windows too.

Best regards
Espen Harlinn

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