Is this OK.

[TechnoTone]

I'm a little nervous of this class that I have just written as it's doing some overloading and inheriting and as I'm new to all this I am unsure as to whether I've done it correctly. It all seems to work OK but I'd feel happier having some experts give it the once-over.

Here is the class in question:

Public Class bofaException
   Inherits Exception

   Public Sub New()
      MyBase.New()
   End Sub

   Public Sub New(ByVal ex As Exception)
      MyBase.New(GeneralUtilities.ExceptionString(ex))
   End Sub

   Public Sub New(ByVal ex As Exception, ByVal Source As String)
      MyBase.New(GeneralUtilities.ExceptionString(ex, Source))
   End Sub

   Public Sub New(ByVal ex As Exception, ByVal Source As String, ByVal Message As String)
      MyBase.New(GeneralUtilities.ExceptionString(ex, Source, Message))
   End Sub

   Public Sub New(ByVal ex As Exception, ByVal Source As String, ByVal Message As String, ByVal ShowStack As Boolean)
      MyBase.New(GeneralUtilities.ExceptionString(ex, Source, Message, ShowStack))
   End Sub

End Class

Here is the GeneralUtilities class:

Public Class GeneralUtilities

   Shared Function ExceptionString(ByVal ex As Exception, Optional ByVal Source As String = "", Optional ByVal Message As String = "", Optional ByVal ShowStack As Boolean = False) As String

      If Message <> "" Then Message &= Environment.NewLine

      Message &= "Error source:    " & Microsoft.VisualBasic.vbTab & ex.Source
      If Source <> "" Then Message &= ": " & Source.Trim

      If ShowStack And (ex.StackTrace.Length > 0) Then
         Dim sPrefix As String
         Dim sStackString As String

         sPrefix = Environment.NewLine & "Stack trace:    " & Microsoft.VisualBasic.vbTab
         sStackString = ex.StackTrace.Trim

         While sStackString.Length > 0
            If sStackString.Substring(0, 2) = "at" Then
               If sStackString.IndexOf(" in ") > 0 Then
                  Message &= sPrefix & sStackString.Substring(0, sStackString.IndexOf(" in ", 4)).Trim
                  sStackString = sStackString.Remove(0, sStackString.IndexOf(" in ", 4)).Trim
                  sPrefix = Environment.NewLine & "                       " & Microsoft.VisualBasic.vbTab
               Else
                  Message &= sPrefix & sStackString
                  sStackString = ""
               End If
            End If
            If sStackString.Substring(0, 2) = "in" Then
               If sStackString.IndexOf(" at ") > 0 Then
                  Message &= sPrefix & sStackString.Substring(0, sStackString.IndexOf(" at ", 4)).Trim.Insert(3, " ")
                  sStackString = sStackString.Remove(0, sStackString.IndexOf(" at ", 4)).Trim
                  sPrefix = Environment.NewLine & "                       " & Microsoft.VisualBasic.vbTab
               Else
                  Message &= sPrefix & sStackString.Insert(3, " ")
                  sStackString = ""
               End If
            End If
         End While
      End If

      If ShowStack Then
         Message &= Environment.NewLine & Environment.NewLine & "Error message: " & Microsoft.VisualBasic.vbTab & ex.Message
      Else
         Message &= Environment.NewLine & "Error message: " & Microsoft.VisualBasic.vbTab & ex.Message
      End If

      ExceptionString = Message

   End Function

End Class

The idea of this is that when we get errors in our classes we can pass them back up the call-stack until we get to a position where we want to display the error. It will then show a complete list of all the levels involved in the error.

For example, this is the exception handler of a property:

Throw New bofaException(ex, "SecurityUtilities: PassApplicationID property set", "An error occurred while setting the property.", True)

...and this is the exception handler of a button click event which will display a message box showing the errors that occurred:

MessageBox.Show(GeneralUtilities.ExceptionString(ex, "ColumnHeaderButton1_Click", "OOPS!!!"))