Q:

Why dont have ConfigurationManager?

I was trying to use ConfigurationManager, at first System.Configuration didnt have it and I was wondering why.

After some tries, after include the reference System.Configuration now it show.

So how is I can use System.Configuration without reference? But need the reference to use System.Configuration.ConfigurationManager 

A:

In .net1.0 and 1.1 the namespace System.Configuration was under System.dll.
Since .net2.0 there's a new assembly - System.Configuration.dll.
Back at the days we had to use ConfigurationSettings, which is in the System.dll assembly and is obsolete now.
Now, we are using ConfigurationManager and its in the System.Configuration.dll assembly.
So, the reason you are getting System.Configuration is probably because you are referencing System.dll which is included by default in winforms applications.

