private void ListEndTreatments(Document doc, List<Rebar> bars)
{
    StringBuilder info = new StringBuilder();
    for (int n = 0; n < bars.Count; n++)
    {
        // get end treatment for both ends of bar
        for (int i = 0; i < 2; i++)
        {
            ElementId treatmentTypeId = bars[n].GetEndTreatmentTypeId(i);
            if (treatmentTypeId != ElementId.InvalidElementId)
            {
                EndTreatmentType treatmentType = doc.GetElement(treatmentTypeId) as EndTreatmentType;
                info.AppendLine(string.Format("End treatment for bar {0} end {1}: {2}", n, i, treatmentType.EndTreatment));
            }
        }
    }

    TaskDialog.Show("Revit", info.ToString());
}

Private Sub ListEndTreatments(doc As Document, bars As List(Of Rebar))
    Dim info As New StringBuilder()
    For n As Integer = 0 To bars.Count - 1
        ' get end treatment for both ends of bar
        For i As Integer = 0 To 1
            Dim treatmentTypeId As ElementId = bars(n).GetEndTreatmentTypeId(i)
            If treatmentTypeId <> ElementId.InvalidElementId Then
                Dim treatmentType As EndTreatmentType = TryCast(doc.GetElement(treatmentTypeId), EndTreatmentType)
                info.AppendLine(String.Format("End treatment for bar {0} end {1}: {2}", n, i, treatmentType.EndTreatment))
            End If
        Next
    Next

    TaskDialog.Show("Revit", info.ToString())
End Sub