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Methods of 'System.Nullable(Of T)' cannot be used as operands of the 'AddressOf' operator

A statement uses the AddressOf operator with an operand that represents a procedure of the Nullable structure.

Error ID: BC32126

To correct this error

  • Replace the procedure name in the AddressOf clause with an operand that is not a member of Nullable.

  • Write a class that wraps the method of Nullable that you want to use. In the following example, the NullableWrapper class defines a new method named GetValueOrDefault. Because this new method is not a member of Nullable, it can be applied to nullInstance, an instance of a nullable type, to form an argument for AddressOf.

    Module Module1
        Delegate Function Deleg() As Integer
        Sub Main()
            Dim nullInstance As New Nullable(Of Integer)(1)
            Dim del As Deleg
            ' GetValueOrDefault is a method of the Nullable generic
            ' type. It cannot be used as an operand of AddressOf.
            ' del = AddressOf nullInstance.GetValueOrDefault
            ' The following line uses the GetValueOrDefault method
            ' defined in the NullableWrapper class.
            del = AddressOf (New NullableWrapper(
                Of Integer)(nullInstance)).GetValueOrDefault
        End Sub
        Class NullableWrapper(Of T As Structure)
            Private m_Value As Nullable(Of T)
            Sub New(ByVal Value As Nullable(Of T))
                m_Value = Value
            End Sub
            Public Function GetValueOrDefault() As T
                Return m_Value.Value
            End Function
        End Class
    End Module