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How to find what type or class an instance is based on |
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Its alway very useful in VB.NET/ASP.NET to be able to find out whether or not a class is of a particular type, or is inherited.
You can do this by using the typeof keyword in VB.NET
for example if we were overloading an Arraylist, but wanting to check that an add is of the correct type when we could use the following snippet
Imports Microsoft.VisualBasic
Namespace Shop
Public Class OrderLinesCollection
Inherits ArrayList
Public Overrides Function Add(ByVal value As Object) As Integer
If TypeOf value Is OrderLine Then
Return MyBase.Add(value)
Else
Throw New NotSupportedException("You can only add OrderLines to this collection")
End If
End Function
End Class
End Namespace
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VB.NET/ASP.NET