错误所在事件：项目,AfterOpenProject
详细错误信息：
未将对象引用设置到对象的实例。

好像是下段代码出了问题， 请老师帮忙检查更改一下

Dim drs As New List(of DataRow)
With DataTables("库存明细表")
    For Each nm As String In .GetValues("产品ID") \'找出每个产品的第一行数据, 添加到集合drs中
        drs.Add(.Find("产品ID = \'" & nm & "\'", "[_SortKey]"))
    Next
    For Each r As DataRow In drs
        .DataCols("入库数量").RaiseDataColChanged(r) \'重置每个产品的第一行
    Next
End With

谢谢老师！ 是库存明细表的datacolchanged事件吗？

Select Case e.DataCol.Name
    Case "产品ID","入库数量","出库数量"
        Dim dr As DataRow
        Dim mr As DataRow = e.DataRow
        Dim drs As List(of DataRow)
        dr = e.DataTable.Find("[_SortKey] < " & mr("_SortKey") & " And [产品ID] = \'" & mr("产品ID") & "\'", "[_SortKey] Desc")
        If dr Is Nothing Then
            mr("库存数量") = mr("入库数量") - mr("出库数量")
            dr = mr
        End If
        drs = e.DataTable.Select("[_SortKey] >= " & dr("_SortKey") & " And [产品ID] = \'" & dr("产品ID") & "\'", "[_SortKey]")
        For i As Integer = 1 To drs.Count - 1
            drs(i)("库存数量") = drs(i-1)("库存数量") + drs(i)("入库数量") - drs(i)("出库数量")
        Next
        If e.DataCol.Name = "产品ID" AndAlso e.OldValue IsNot Nothing AndAlso e.OldValue <> e.NewValue Then
            dr = e.DataTable.Find("[_SortKey] < " & mr("_SortKey") & " And [产品ID] = \'" & e.OldValue & "\'", "[_SortKey] Desc")
            If dr Is Nothing Then
                dr = e.DataTable.Find("[产品ID] = \'" & e.OldValue & "\'", "[_SortKey]")
                If dr IsNot Nothing Then
                    dr("库存数量") = dr("入库数量") - dr("出库数量")
                End If
            End If
            If dr IsNot Nothing Then
                drs = e.DataTable.Select("[_SortKey] >= " & dr("_SortKey") & " And [产品ID] = \'" & dr("产品ID") & "\'", "[_SortKey]")
                For i As Integer = 1 To drs.Count - 1
                    drs(i)("库存数量") = drs(i-1)("库存数量") + drs(i)("入库数量") - drs(i)("出库数量")
                Next
            End If
        End If
End Select

 试试改一下

Dim drs As New List(of DataRow)
With DataTables("库存明细表")
    For Each nm As String In .GetValues("产品ID", "产品ID is not null") \'找出每个产品的第一行数据, 添加到集合drs中
        drs.Add(.Find("产品ID = \'" & nm & "\'", "[_SortKey]"))
    Next
    For Each r As DataRow In drs
        .DataCols("入库数量").RaiseDataColChanged(r) \'重置每个产品的第一行
    Next
End With

OK了， 谢谢老师！