With a vector defined as `std::vector<std::string>`,
Wondering why the following is valid:

```
if ( vecMetaData[0] != "Some string" ) 
{
    ...

```

But not this:

```
switch ( vecMetaData[1] )
{
    ...

```

Visual studio complains :

```
error C2450: switch expression of type 'std::basic_string<_Elem,_Traits,_Ax>' is illegal
1>        with
1>        [
1>            _Elem=char,
1>            _Traits=std::char_traits<char>,
1>            _Ax=std::allocator<char>
1>        ]
1>        No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

```