dim vFunction as string
vFunction="evaluateTest"
call vFunction
or
return=vFunction

You can use the CallByName VB methode of the
Microsoft.VisualBasic.Interaction class.

Or you can create your own function

    Public Function MyCallByName(ByVal O As Object, ByVal functionName As
String, ByVal Parameters() As Object) As Object
        Try
            Dim T As Type
            Dim MI As MethodInfo
            Dim ParamTypes(Parameters.Length - 1) As Type
            Dim i As Integer

            For i = 0 To Parameters.Length - 1
                ParamTypes(i) = Parameters(i).GetType
            Next i

            T = O.GetType
            MI = T.GetMethod(functionName, ParamTypes)

            Return MI.Invoke(O, Parameters)

            MI = Nothing
            T = Nothing
        Catch
            Return Nothing
        End Try
    End Function

The first parameter is the object or the module where the function is
implemented.

For exemple, you can use the functions like that :

Dim S As String

S = ""
S = S.Concat("Essai", " Toto")
Debug.WriteLine(S)

S = ""
S = CType(CallByName(S, "Concat", CallType.Method, New Object() {"Essai", "
Toto"}), String)
Debug.WriteLine(S)

S = ""
S = CType(MyCallByName(S, "Concat", New Object() {"Essai", " Toto"}),
String)
Debug.WriteLine(S)