C# syntax - Colon after a variable name

Question

Quick question; I\'ve recently upgraded to VS2010, and got the new version of ReSharper.

Now, when ReSharper is giving me autocomplete options for a variable, it give me

Answer 1

The second is for C# 4.0 named arguments. And here's a link on MSDN.

Answer 2

The colon is necessary to indicate parameters. In C# 4.0, you can re-order and name your parameters, optionally, but the variable name must match the prototype and have the colon postfix.

public void Test(string something1, string something2)
{
}

can be called as:

Test(something2: "bar", something1: "foo");

if you want