AOP with PostSharp: Listing 2.
Handling selected exceptions in the aspect
Aspect-Oriented Programming
' <ExceptionWrapper() >
' <ExceptionWrapper(HandleExceptionSingleType:=GetType(OverflowException)) >
' <ExceptionWrapper(HandleExceptionSingleType:=GetType(DivideByZeroException)) >
' <ExceptionWrapper(HandleExceptionTypeArray:={GetType(OverflowException), _
GetType(DivideByZeroException)}) >
Public Property HandleExceptionTypeArray As Type()
Public Property HandleExceptionSingleType As Type
Public Overrides Function GetExceptionType( _
targetMethod As System.Reflection.MethodBase) As System.Type
Dim result As Type = Nothing
Dim MethodExceptionType = MyBase.GetExceptionType(targetMethod)
'If no explict exception types specified, handle any type of exception
If IsNothing(HandleExceptionSingleType) AndAlso IsNothing( _
HandleExceptionTypeArray) Then
result = MethodExceptionType
Else
'If there is a named single exception type and it is a match, handle it
If IsNothing(HandleExceptionSingleType) = False AndAlso _
HandleExceptionSingleType = MethodExceptionType Then
result = MethodExceptionType
End If
'If there is an array of exception types, and not already a match,
'handle the exception if any in the array are a match
If IsNothing(HandleExceptionTypeArray) = False AndAlso IsNothing(result) = True Then
For Each testType In HandleExceptionTypeArray
If testType = MethodExceptionType Then
result = MethodExceptionType
End If
Next
End If
End If
'Will be nothing only if types specified and no match
Return result
End Function
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].