ASP.NET in a Nutshell

Name

Unload

Synopsis

Sub Page_Unload(Sender As Object, e As EventArgs)
   ‘cleanup code
End Sub

Fired when the page is unloaded from memory. Since this event is fired before the page is unloaded, we can perform cleanup operations, such as closing open files and database connections.

The Unload event is passed the following arguments by ASP.NET:

Sender

An argument containing information about the object that raised the event.

e

An object of type EventArgs containing additional information about the event.

Example

The example demonstrates the Unload event by closing a file that was opened for display in the Page_Load event handler:

Dim TheFile As System.IO.StreamReader
Sub Page_Load(  )
   TheFile = System.IO.File.OpenText(MapPath("Init.aspx"))
   Message.Text = "<pre>" & _
      Server.HtmlEncode(TheFile.ReadToEnd(  )) & "</pre>"
End Sub
  
Sub Page_Unload(  )
   TheFile.Close(  )
End Sub

Notes

While the Unload event is useful for performing page-level cleanup tasks, for resources such as databases, for which it is possible that an exception will interrupt the normal flow of page processing, it may be better to place the cleanup code for that resource in the Finally block of a Try...Catch...Finally statement, which will ensure that the cleanup code is always executed. For more information on Try...Catch...Finally, see Chapter 10.

Note that the Sender and e arguments are optional for this event, as shown in the example.

When the AutoEventWireup attribute of the @ Page directive is set to True (the default), ASP.NET ...