syntax - In c# what does 'where T : class' mean?

Question

In C# what does where T : class mean?

Ie.

public IList<T> DoThis<T>() where T : class

Answer 1

Simply put this is constraining the generic parameter to a class (or more specifically a reference type which could be a class, interface, delegate, or array type).

See this MSDN article for further details.