มีใครช่วยผมได้บ้าง เรื่องของ Throw New Exception("HasAccountTransection") win app vb2008

Try
   ...
   If <ตรวจสอบความผิดพลาด> Then Throw New Exception("มีความผิดพลาด")
Catch ex As Exception
    Messagebox.Show(ex.Message)
End Try

Public Class MyDeleteGridEventArgs
	Inherits EventArgs
	Private _IsError As Boolean = False
	Private _Ex As Exception = Nothing

	Public Property IsError() As Boolean
		Get
			Return _IsError
		End Get
		Set
			_IsError = value
		End Set
	End Property

	Public Property Ex() As Exception
		Get
			Return _Ex
		End Get
		Set
			_Ex = value
			_IsError = (value IsNot Nothing)
		End Set
	End Property

	Public Sub New(argIsError As Boolean)
		_IsError = argIsError
	End Sub
	Public Sub New(argEx As Exception)
		Me.Ex = argEx
	End Sub
End Class

Class ....

    Delegate Sub OnGridRowDeleteHandler ( ByVal Sender As Object ,ByVal e As MyDeleteGridEventArgs )

    Public Event OnGridRowDeleteCancel AS OnGridRowDeleteHandler 

    ...
    ...
    ...

    Private Sub dt_RowDelete( ByVal Sender As Object ,ByVal e As DataRowChangedEvent ) Handles dt.RowDeleted
       if CancelAction Then
           
           CancelAction = False
           e.Row.RejectChanges()

           Dim ex As Exception = New Exception ("Has account transaction.")
           Dim myEventArgs As MyDeleteGridEventArgs = New MyDeleteGridEventArgs (ex)
        
           RaiseEvent OnGridRowDeleteCancel ( Sender ,myEventArgs )
       End If
    End Suub

    ...
    ...
    ...

End Class    

Public Class MyDeleteGridEventArgs
	
        Private _AllowDeleted As Exception = Nothing
        Private _DeleteAcquirorName As String = String.Empty

	Public Property AllowDeleted() As Boolean
		Get
			Return _AllowDeleted
		End Get
		Set
			_AllowDeleted = value			
		End Set
	End Property
        
        'Relax checking with no case-sensitive
        Public Property _DeleteAcquirorName () As String
		Get
			Return _DeleteAcquirorName 
		End Get
		Set
			_DeleteAcquirorName = value.ToUpper()			
		End Set
	End Property

        'Basic Constructor
        Public Sub New ()
        End Sub
 
        'Take Parameter Constructor
	Public Sub New( ByVal varAllowDeleted As Boolean, ByVal varDeleteAcquirorName As String )
		_DeleteAcquirorName = varDeleteAcquirorName 
                _AllowDeleted = varAllowDeleted 
	End Sub
	
End Class

Class ....

    Delegate Sub DeleteAccountDeleteHandler ( ByVal Sender As Object ,ByVal e As MyDeleteGridEventArgs )

    Public Overridable Sub BeginDeleteAccountDataHandler  ( ByVal Sender As Object ,ByVal e As MyDeleteGridEventArgs )
        
          Select Case e.DeleteAcquirorName 
              Case "MAINGRID" :
                  ' Check Bussiness rules with MAINGRIDaccquire
                  ' If valid Set AllowDeleted = true
                  ' Suppose custom function name CheckedDeletableWithBussinessRuleWithMainGrid
                  e.AllowDeleted = CheckedDeletableWithBussinessRuleWithMainGrid() 
              Case Else       
                   ' Suppose custom function name CheckedDeletableWithBussinessRuleByDefault
                  e.AllowDeleted = CheckedDeletableWithBussinessRuleByDefault() 
          End Select 

    End Sub

    ...
    ...
    ...

    Private Sub dt_RowDelete( ByVal Sender As Object ,ByVal e As DataRowChangedEvent ) Handles dt.RowDeleted

        Dim myEventArgs As MyDeleteGridEventArgs = New MyDeleteGridEventArgs ()
        myEventArgs.DeleteAcquirorName  = "MAINGRID"
        BeginDeleteAccountDataHandler  (  myEventArgs  )

        'Bypass delete with bussiness logic
        If (Not myEventArgs.AllowDeleted ) Then
              e.Row.RejectChanges()
        End if
      
    End Sub

    ...
    ...
    ...

End Class