ASP.NET

Try
'Error if the user inputs some string
Dim strCode As Integer= Request.QueryString("Code")

Catch ex As Exception
Response.Write(Request.QueryString("Code"))
End Try

Response.Write(Request.QueryString("strCode"))

Try
            'Error if the user inputs some string
            Dim strCode As Integer= Request.QueryString("Code")
        Catch ex As Exception
            Response.Write("Invalid code")
        End Try

 Try
            'Error if the user inputs some string
            Dim strCode As Integer= Request.QueryString("Age")
        Catch ex As Exception
            Response.Write("Invalid Age")
        End Try

Try
            'Error if the user inputs some string
            Dim strCode As Integer= Request.QueryString("Code")
            Dim strCode As Integer= Request.QueryString("Age")
        Catch ex As Exception
            Dim strDescription as string=String.Empty
            'Check for the value generted the eror 
            'and assign description

            Response.Write("Invalid" & strDescription )  
        End Try

Fred_Smith wrote:

How do I set about protecting .pdf, .doc, jpg etc files from unauthorised access in this way?