Convert.ToInt32 does not work, get error

I just want to convert a object to an integer.

slot_number = Convert.ToInt32(client.HostGame.data["map_slots"]);

I get this error "The name `Convert' does not exist in the current context" I guess I miss the library (using..), but I fount no fitting lib

Hope someone can help

You can always try System.Convert.ToInt32(...)

But I think you just missing:

using System;