【解决方法：】

可以在给该字段赋值后，调用以下代码：

1、单据体字段

Call DoAction("FQty",1) 'FQty为该字段的关键字，1为行号

2、单据头字段

Call DoAction("FDecimal", -1) 'FDecimal为该字段的关键字

Private Sub DoAction(ByVal strKey As String, Optional ByVal Row As Long = -1)
Dim dctTemp As KFO.Dictionary, dctTempFld As KFO.Dictionary

Set dctTemp = m_BillInterface.GetFieldInfoByKey(strKey, "", 0)
Set dctTempFld = m_BillInterface.GetDataFld(dctTemp)
m_BillInterface.BillCtl.DoAction dctTemp, dctTempFld, Row

Set dctTemp = Nothing
Set dctTempFld = Nothing
End Sub