How to: Add or Remove Imported Namespaces (Visual Basic)
Importing a namespace allows you to use elements from that namespace in your code without fully qualifying the element. For example, if you want to access the Create method in the System.Messaging.MessageQueue class, you can import the System.Messaging namespace and just refer to the element you need in code as MessageQueue.Create.
Imported namespaces are managed on the References page of the Project Designer. The imports you specify in this dialog box are passed directly to the compiler (/imports) and apply to all files in your project. Use the Imports statement to use a namespace in a single source code file.
To add an imported namespace
In Solution Explorer, double-click the My Project node for the project.
In the Project Designer, click the References tab.
In the Imported Namespaces list, select the check box for the namespace that you wish to add.
Note
In order to be imported, the namespace must be in a referenced component. If the namespace does not appear in the list, you will need to add a reference to the component that contains it. For more information, see How to: Add or Remove References in Visual Studio.
To remove an imported namespace
In Solution Explorer, double-click the My Project node for the project.
In the Project Designer, click the References tab.
In the Imported Namespaces list, clear the check box for the namespace that you wish to remove.
User Imports
User imports allow you to import a specific class within a namespace rather than the entire namespace. For example, your application might have an import for the Systems.Diagnostics namespace, but the only class within that namespace that you are interested in is the Debug class. You can define System.Diagnostics.Debug as a user import, and then remove the import for System.Diagnostics.
If you later change you mind and decide that was really the EventLog class that you needed, you could enter System.Diagnostics.EventLog as a user import and overwrite System.Diagnostics.Debug using the update functionality.
To add a user import
In Solution Explorer, double-click the My Project node for the project.
In the Project Designer, click the References tab.
In the text box below the Imported Namespaces list, enter the full name for the namespace you wish to import, including the root namespace.
Click the Add user import button to add the namespace to the Imported Namespaces list.
Note
The Add user import button will be disabled if the namespace matches one already in the list; you cannot add an import twice.
To update a user import
In Solution Explorer, double-click the My Project node for the project.
In the Project Designer, click the References tab.
In the Imported Namespaces list, select the namespace you wish to change.
In the text box below the Imported Namespaces list, enter the name for the new namespace.
Click the Update user import button to update the namespace in the Imported Namespaces list.