为什么不能将字符串变量分配给json :: value对象？

Question

This initialization is possible and can make the json::value object with the value of "hello1" as follows.

json::value v1 = json::value::string(U("hello1")); // ok

But this initialization is not working. What is the reason for that? How to create a JSON object by using the value of a variable such as string or char*.

string str1 = "Hello2";
    json::value v2 = json::value::string(str1);   //Error (1)
    json::value v3 = json::value::string(U(str1)); //Error (2)

Error 1

Severity    Code    Description Project File    Line    Suppression State
Error   C2248   'web::json::value::string': cannot access private member declared in class 'web::json::value'   StolenDetailsService    c:\users\nuwanst\source\repos\stolendetailsservice\stolendetailsservice\dbhandler.cpp   62  

Error 2

Severity    Code    Description Project File    Line    Suppression State
Error   C2065   'Lstr1': undeclared identifier  StolenDetailsService    c:\users\nuwanst\source\repos\stolendetailsservice\stolendetailsservice\dbhandler.cpp   62  

Answer 1

I used streams. It works for me.

   string st1="Hello";
    utility::stringstream_t ss1;
    ss1 << str1;
    json::value Jobj = json::value::parse(ss1);