Server.GetLastError

Hello,
I am trying to get the last occured error via the
following code:
Sub Page_Load(...)
Dim zero As Integer = 0
Try
Dim err As Integer = 10 / zero
Catch ex As Exception
End Try
Response.write(Server.GetLastError.Message)
End Sub
However the above code always throws an error at the
response.write line with:
Object reference not set to an instance of an object.
Anybody knows why this is happening?Well, first off 10/0 will not throw an error. I also assume you must have
Option Strict Off or your code would not even compile: err would need to be
dimmed as a double or you would need ctype(10/zero, double) for code to
compile.
I think GetLastError only returns the last unhandled error, during the
current context, and I think the page's Page_Error event or global.asax
Application_Error event has to be raised to access it. Once one of those
events is raised Server.GetLastError is available anywhere in your
code...for the remainder of the current context / request
Example:
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Dim zero As Integer = 0
Dim err As Double = 10 / CType("x", Integer)
End Sub
Private Sub Page_Error(ByVal sender As Object, ByVal e As System.EventArgs)
Handles MyBase.Error
Response.Write(Server.GetLastError.Message)
End Sub
Or since it's now available anywhere, you could also do something like this:
Private Sub Page_Error(ByVal sender As Object, ByVal e As System.EventArgs)
Handles MyBase.Error
Server.Transfer("error.aspx")
End Sub
And then in error.aspx
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
Response.Write(Server.GetLastError.Message)
End Sub
"VK" <anonymous@.discussions.microsoft.com> wrote in message
news:0dfb01c54132$353bf820$a401280a@.phx.gbl...
> Hello,
> I am trying to get the last occured error via the
> following code:
> Sub Page_Load(...)
> Dim zero As Integer = 0
> Try
> Dim err As Integer = 10 / zero
> Catch ex As Exception
> End Try
> Response.write(Server.GetLastError.Message)
> End Sub
> However the above code always throws an error at the
> response.write line with:
> Object reference not set to an instance of an object.
> Anybody knows why this is happening?
Since you are catching the exception, it is no longer an error.
bill
"VK" <anonymous@.discussions.microsoft.com> wrote in message
news:0dfb01c54132$353bf820$a401280a@.phx.gbl...
> Hello,
> I am trying to get the last occured error via the
> following code:
> Sub Page_Load(...)
> Dim zero As Integer = 0
> Try
> Dim err As Integer = 10 / zero
> Catch ex As Exception
> End Try
> Response.write(Server.GetLastError.Message)
> End Sub
> However the above code always throws an error at the
> response.write line with:
> Object reference not set to an instance of an object.
> Anybody knows why this is happening?
Hello VK,
If this code would generate an error (which it wont as detailed by Brad),
you're swallowing it anyways. You need to remove the try/catch.
Matt Berther
http://www.mattberther.com

> Hello,
> I am trying to get the last occured error via the following code:
> Sub Page_Load(...)
> Dim zero As Integer = 0
> Try
> Dim err As Integer = 10 / zero
> Catch ex As Exception
> End Try
> Response.write(Server.GetLastError.Message)
> End Sub
> However the above code always throws an error at the response.write
> line with:
> Object reference not set to an instance of an object.
> Anybody knows why this is happening?
>