Visual Studio.NET Namespaces

Author : Exforsys Inc. Published on: 7th Jun 2005 | Last Updated on: 24th Dec 2007

Visual Studio.NET Namespaces

The .NET Framework class library has thousands of classes which are needed for developing and deploying solutions. In order to organize all those classes for ease of use .NET Framework uses namespaces. This Gives the Classes their own space and prevents conflicts between the various names in these classes. For instance if two classes contain a method Paint(), then to avoid conflicts in names we can place these classes in two different namespaces. Thus namespaces allow classes to be grouped in a consistent, hierarchical manner.

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The writing convention is that the word after the right–most dot is the name of the type and the string up to the dot is the name of the namespace. We shall see an example of this in the following statement.

System.Windows.Forms.Button

In the above statement the name of the namespace is System.Windows.Form and the type name is Button.

A namespace can contain classes, structures, enumerations, delegates, interfaces, and other namespaces. Namespaces can be nested and can have any number of members. The typical namespaces begin with Microsoft or System. The new namespace My is added in .NET 2005. If there is a conflict in the namespace in such a way that even fully qualified Object name is also not usable, then the classes cannot be used.

You can create a namespace by using the Namespace … End Namespace block. With in the namespace Block, you can create classes, enumerations, structures, delegates, interfaces, or other namespaces. It is not imperative that all the code should be kept in one single file. A namespace can span multiple files and even multiple assemblies.

Namespace VBTutorial

Class Class1

…….

End Class

Namespace Lesson2

Class Class2

…..

Public Sub Teach()

End Sub

End Class

End namespace

End Namespace

In order to access the methods teach defined in class2 you have to instantiate the class Class2.
Dim lessonObj as new VBTutorial.Lesson2.Class2

lessonObj.Teach()

Alternatively you can use the following lines of code:

Imports VBTutorial.Lesson2
Dim lessonObj as new Class2
lessonObj.Teach()

Let us quickly see some of the namespaces defined in .NET

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System.ComponentModel	Liending and design time implementation of components
System.Data	Data Access
System.Data.SQLClient	SQL Server data access
System.Data.OLEDB	OLE DB data access
System.Data.SML	XML processing
System.Diagnostics	Provides debugging and tracing services
System.Messaging	Microsoft Message Queue management
System.Net	Programmable access to network protocol
My.Computer	Gives access to local computer
My.User	Gives access to the local user logged in