Anders Hesselbom

Visual Basic: Importing namespaces

2011-05-07

In C# you can use the using directive to import the classes in a given namespace to your current scope. If you want to use the classes in System.Data.SqlClient, you could refer to them using their full path, like so:

var r = new System.Data.SqlClient.SqlDataAdapter();

You can add namespaces to your scope by adding a using directive in the beginning of your source file. If you add this directive:

using System.Data.SqlClient;

You could then access the SqlDataAdapter class in your code, without typing the full path, like so:

var r = new SqlDataAdapter();

Visual Basic does not have the using directive, but it has a more powerful directive called Imports. Imports can import both classes and other namespaces. The code that creates a SqlDataAdapter in Visual Basic looks like this:

Dim R As New System.Data.SqlClient.SqlDataAdapter()

If you use the Imports directive to import System.Data in the beginning of your file, like so:

Imports System.Data

You can access both the namespaces (like SqlClient) and the classes in System.Data without providing the full path.

Dim R As New SqlClient.SqlDataAdapter()

If course, you can go on and import the SqlClient namespace to access the SqlDataAdapter class without specifying it’s full path, just as you can do in C#. So, the using directive in C# can import classes, but the Imports directive in VB imports both classes and namespaces.

Categories: VB.NET