from System import DateTime

from Kingdee.BOS.Core import *

def BeforeSave(e):

counts = this.Model.GetEntryRowCount("FPAYBILLENTRY") ---单据明细的ID

for i in range(counts):

x = this.Model.GetValue("FCOSTID",i)

if  x is not None: 

this.Model.SetValue("FCOMMENT",str(this.Model.GetValue("FCOSTID",i)["NAME"]),i)

丁老师厉害