AOP with PostSharp: Listing 1.
A simple error-handling aspect
Module Module1
Sub Main()
Try
Call CreateError()
Trace.WriteLine("OnExceptionAspect_Demo: Returned from CreateError")
Catch ex As Exception
Trace.WriteLine("")
Trace.WriteLine("An Application Error Ocurred. " & ex.Message)
End Try
End Sub
<ExceptionWrapper() >
Sub CreateError()
Dim zero As Integer = 0
Dim DivByZero As Integer = 10 / zero
Trace.WriteLine("Numerator Divided by Zero:", DivByZero.ToString)
End Sub
<Serializable() >
Public Class ExceptionWrapper
Inherits PostSharp.Aspects.OnExceptionAspect
Public Overrides Sub OnException( _
args As PostSharp.Aspects.MethodExecutionArgs)
Dim ErrorID = Guid.NewGuid
Dim TraceMsg1 = String.Format("PostSharp: Error ID = {0}", ErrorID)
Dim TraceMsg2 = String.Format( _
"PostSharp: {0} had an error at {1} of type {2}",
args.Method.Name, DateTime.Now, args.Exception)
Trace.WriteLine("PostSharp Detected An Application Error")
Trace.WriteLine(TraceMsg1)
Trace.WriteLine(TraceMsg2)
Trace.WriteLine("")
Dim ExceptionMsg = String.Format( _
"Please contact support with Error ID: {0}", ErrorID)
Throw New Exception(ExceptionMsg, innerException:=args.Exception)
End Sub
End Class
End Module
About the Author
Joe Kunk is a Microsoft MVP in Visual Basic, three-time president of the Greater Lansing User Group for .NET, and developer for Dart Container Corporation of Mason, Michigan. He's been developing software for over 30 years and has worked in the education, government, financial and manufacturing industries. Kunk's co-authored the book "Professional DevExpress ASP.NET Controls" (Wrox Programmer to Programmer, 2009). He can be reached via email at [email protected].