Handling Page Level Errors

The Page_Error() event, exposed by the Page object, can be used to catch errors on a

page level.The following code demonstrates how you can use this event for page level

error handling.

In <script runat="server" /> block or codebehind:

Private Sub Page_Load(Source As Object, E As EventArgs)

Dim _Connection As New

➥SqlConnection("Server=localhost;Database=pubs;uid=sa;pwd=;")

Dim _Command As New SqlCommand("Select * From Authors", _Connection)

'_Connection.Open() causes an exception

DG1.DataSource = _Command.ExecuteReader(CommandBehavior.CloseConnection)

DG1.DataBind()

_Connection.Close()

End Sub

Public Sub Page_Error(Source As Object, E As EventArgs)

Response.Write(Server.GetLastError.ToString())

Server.ClearError()

End Sub

Comments

The demonstrated code tries to execute a query without having an open connection to

the datasource.This raises an exception, which is captured by the Page_Error() event of

the Page object itself.Within the Page_Error event, the code displays the error message

by calling the GetLastError method of the Server object.This returns an exception

object that is generated by the error. Note that the data access technique used in this

code is not a good approach for connecting to datasources; it has been adopted here

only for demonstrating the Page_Error event.You should always use the

Try/Catch/Finally statements for interacting with datasources.

Errors can also be handled at the application level using the Application_Error

event found in global.asax.

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