Try
Dim objpartdoc As PartDocument
objpartdoc = objapp.ActiveDocument
If objpartdoc.DocumentType = DocumentTypeEnum.kPartDocumentObject Then
Dim objPartCompDef As PartComponentDefinition
objPartCompDef = objpartdoc.ComponentDefinition
'Dim part = objPartCompDef.Occurrences.Item(1).Constraints.Item(1)
Dim objBrawserpanes As BrowserPanes
objBrawserpanes = objapp.ActiveDocument.BrowserPanes
Dim browserPan As Inventor.BrowserPane = (From _Pan As BrowserPane In objBrawserpanes Where _Pan.TreeBrowser Select _Pan).FirstOrDefault
Dim DoDelete As Boolean = False
Dim ObjCollection As ObjectCollection = objapp.TransientObjects.CreateObjectCollection()
For Each _node As BrowserNode In browserPan.TopNode.BrowserNodes
If DoDelete Then
Dim obj = _node.NativeObject
ObjCollection.Add(obj)
End If
Dim def = _node.BrowserNodeDefinition
Dim x = def.Label
If x.ToUpper().Contains("END OF PART") Then
DoDelete = True
End If
Next
objPartCompDef.DeleteObjects(ObjCollection)
Else
MessageBox.Show("Please Open Part Document...")
End If