DataListsTreeTryGetParameterT(String, T, Boolean) - метод

public bool TryGetParameter<T>(
	string parameterName,
	out T parameterValue,
	bool withSystemParameters
)

Public Function TryGetParameter(Of T) ( 
	parameterName As String,
	<OutAttribute> ByRef parameterValue As T,
	withSystemParameters As Boolean
) As Boolean

Dim instance As DataListsTree
Dim parameterName As String
Dim parameterValue As T
Dim withSystemParameters As Boolean
Dim returnValue As Boolean

returnValue = instance.TryGetParameter(parameterName, 
	parameterValue, withSystemParameters)

JScript не поддерживает универсальные типы и методы.