用三楼的方法就行了,简单可靠。
如果你想自动更新,可以在MainTablechanged事件设置代码:
If MainTable.Name = "备料跟踪登记表" Then
Dim dt_beiliao As DataTable = DataTables("备料跟踪登记表")
Dim dt_ruku As DataTable = DataTables("每日入库")
Dim datas As List(Of String()) = dt_ruku.GetUniqueValues("", "备料单号", "物料代码")
For Each data As String() In datas
Dim filter As String = "备料单号 = '" & data(0) & "' and 物料代码 = '" & data(1) & "'"
Dim fdr As DataRow = dt_beiliao.Find(filter)
If fdr Is Nothing Then
fdr = dt_beiliao.AddNew
fdr("备料单号") = data(0)
fdr("物料代码") = data(1)
End If
fdr("入库数量") = dt_ruku.Compute("sum(入库数量)", filter)
Next
End If