CODEWITHSUNDEEP
c#
Pavel
Pavel

Reputation: 1288

Using and namespace

Where to place using System or other namespaces? Which is the correct or the better way to write code and why? According to my c# trainer it is the second, but everywhere I see the first one. 

using System;
namespace Program
{
    class SomeClass
    {
    }
}

or

namespace Program
{
using System;

    class SomeClass
    {
    }
}

According to my c# trainer it is the second, but everywhere I see the first one.

Upvotes: 0

Views: 299

Answers (4)

NDJ
NDJ

Reputation: 5194

Stylecop by default requires you to put usings inside namespaces - see here; for the following reason: (from linked page):

There are subtle differences between placing using directives within a namespace element, rather than outside of the namespace, including:

  1. Placing using-alias directives within the namespace eliminates compiler confusion between conflicting types.

  2. When multiple namespaces are defined within a single file, placing using directives within the namespace elements scopes references and aliases.

Upvotes: 1

Tyrant
Tyrant

Reputation: 106

The scope of a using directive is limited to the file in which it appears.

Create a using alias to make it easier to qualify an identifier to a namespace or type. The right side of a using alias directive must always be a fully-qualified type regardless of the using directives that come before it.

Create a using directive to use the types in a namespace without having to specify the namespace. A using directive does not give you access to any namespaces that are nested in the namespace you specify.

Refer: http://msdn.microsoft.com/en-us/library/sf0df423.aspx

Upvotes: 3

Georg
Georg

Reputation: 5771

It is your choice. The second can be handy if you have a code file with multiple namespaces, but only want to use a namespace import within one of these namespaces. However, most coding guidelines that I have seen so far specify that a file may only contain one namespace at most and the usings at the top of the file, in alphabetic order.

Upvotes: 2

Dieter B
Dieter B

Reputation: 1142

Using is always on the top of the document.

Upvotes: 0

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