Public Class SomeType1
End Class
Public Class SomeType2
End Class

Dim readOnlyKeyedCollection1 As ReadOnlyKeyedCollection(Of SomeType1, SomeType2)

Dim key As Integer
Dim returnValue As SomeType2
returnValue = readOnlyKeyedCollection1.Item(key)

Dim sampleValue As SomeType2
readOnlyKeyedCollection1.Item(key) = sampleValue

Public Overridable Overloads Property Item( _
		ByVal index As Integer _
) As TValue

public virtual TValue this[
		int index
] {get; set;}

public:
property virtual TValue default[int] {
		TValue get(int index);
		void set(int index, TValue value);
}

public TValue get_Item(
		int index
);
public void set_Item(
		int index
TValue);

JScript does not support Generics.