ModelDoc2:GetEntityName return a empty string ?

Hi,

I work in a Drawing document and I selected a vertex.

Show the following partial code:

Dim mySwApp As SldWorks

Dim myDoc As ModelDoc2

Dim mySelMgr As SelectionMgr

PublicSelName As String = ""

...

For i As Integer = 1 To nbSel

     Dim SelType As Integer = mySelMgr.GetSelectedObjectType3(i, -1)

     Select Case SelType

          Case swSelectType_e.swSelVERTICES

               Dim myVertex As Vertex = mySelMgr.GetSelectedObject6(i, -1)

               SelName = myDoc.GetEntityName(myVertex)

or this methode

               Dim myEntity As Entity = myVertex

               SelName = myDoc.GetEntityName(myEntity)

               SelName = myDoc.GetEntityName(myEntity)

...

SelName is empty ! ?

Tank you for your Help !

SolidworksApi macros