Passing List (Of ChildClass) as parameter to method expecting List (Of ParentClass)?
- by Nicholas
Hi, I have implemented inheritance for two parent classes called Table and Field. Each parent class has several child classes. In the Table parent class, I created a method that expects parameter List(Of Field).
I get an error when trying to pass in parameter List(Of ChildField) to the method that expects a parameter of List(Of Field). The error message is as below:
Value of type
'System.Collections.Generic.List(Of
com.hlb.icisbatch.data.ChildField)'
cannot be converted to
'System.Collections.Generic.List(Of
com.hlb.icisbatch.data.Field)'
My question, is it possible to pass in list of child class as parameter? If it is not a list then it works fine. But somehow it is not possible with lists?
Below is sample class structure:
Table Field
| |
ChildTable ChildField
I have a method in the parent class:
Public Class Table
Public Sub New()
End Sub
Public Overridable Sub setFields(ByVal list As List(Of Field)
'Do work here'
End Sub
End Class
and method in child class:
Public Class ChildTable
Public Sub New(ByVal list As List(Of ChildField)
setFields(ChildField)
End Sub
End Class
