Question

What namespace does StringBuilder belong to?

I typed:

using System.Text.StringBuilder;

But the intellisense, won’t let me type StringBuilder.

Answer 1

Its very easy to determine in which namespace .NET class lives. you have two ways:

1. Find interesting class in MSDN and in Inheritance Hierarchy section you can see FULL class name. Full class name means that before class name would be its namespace. For StringBuilder full class name would face as System.Text.StringBuilder. Just omit class name (StringBuilder) and you get namespace
2. Open Object browser in VS and search for interesting class. In results, click on the class and in detail view interesting information will appear:
   

I always use second way, because its more easy for me.