In c# 3.0, is it possible to add implicit operators to the string class?

Question

something like

public static class StringHelpers
{
    public static char first(this string p1)
    {
        return p1[0];
    }

    public static implicit operator Int32(this string s) //this doesn't work
    {
        return Int32.Parse(s);
    }
}

so :

string str = "123";
char oneLetter = str.first(); //oneLetter = '1'

int answer = str; // Cannot implicitly convert ...

Answer 1

Unfortunately C# does not allow you to add operators to any types that you don't own. Your extension method is about as close as you are going to get.

Answer 2

No, there's no such thing as extension operators (or properties etc) - only extension methods.

The C# team have considered it - there are various interesting things one could do (imagine extension constructors) - but it's not in C# 3.0 or 4.0. See Eric Lippert's blog for more information (as always).

Answer 3

What you are trying to do in your example (defining an implicit operation from string to int) is not allowed.

Since an operation (implicit OR explicit) can only be defined in the class definition of the target or destination class, you cannot define your own operations between framework types.

Answer 4

I am thinking your best bet is something like this:

public static Int32 ToInt32(this string value)
{
    return Int32.Parse(value);
}