Question

I would like to write a generic function that would search a List(Of T) for all elements of type TFilter and return a List(Of TFilter) which comprises those elements. I’ve tried this:

Public Function FilterList(Of T, TFilter)(ByVal ListToFilter As List(Of T)) As List(Of TFilter)
    Return ListToFilter.FindAll(Function(z) z.GetType.Equals(GetType(TFilter))).ConvertAll(New Converter(Of T, TFilter)(Function(z) CType(z, TFilter)))
End Function

But, it gives the following error:

Value of type ‘T’ cannot be converted
to ‘TFilter’.

Is there any way to do this or am I SOL?

Thanks in advance

Answer 1

You need to constrain TFilter to inherit T:

Public Function FilterList(Of T, TFilter As T)(...