目测应该是 试图取控制字符串 位置为1的值.

在操作通过目录树进行数据筛选时提示的，一般出现在打开窗口后， 第一次筛选报错。（但有时候又不报错，所以不解了）

Dim wc As WinForm.Control = e.Sender

If Typeof wc Is winForm.TreeView

    Tables("生产数据查询_Table1").DataSource = DataTables("生产信息子表")

    Tables("生产数据查询_Table1").GrandTotal = False

    Dim dt As DataTable = DataTables("生产信息子表")

    Dim tv1 As WinForm.TreeView = e.Form.Controls("TreeView1")

    Dim tv2 As WinForm.TreeView = e.Form.Controls("TreeView2")

    Dim tv3 As WinForm.TreeView = e.Form.Controls("TreeView3")

    Dim flr As String

    Select Case e.Sender.Name

        Case "TreeView1"

            If tv1.SelectedNode.Name <> "" And  left(tv1.SelectedNode.Name,2) <> "所有"

                Dim year As Integer = tv1.SelectedNode.DataRow("年")

                Dim month As Integer = tv1.SelectedNode.DataRow("月")

                If tv1.SelectedNode.Level = 0

                    Dim y1 As Date = new Date(year,1,1)

                    Dim y2 As Date = new Date(year,12,31)

                    vars("flr1") = "订单日期 >= #" & y1 & "# and 订单日期<= #" & y2 & "#"

                Else

                    Dim m1 As Date = new Date(year,month,1)

                    Dim m2 As Date = new Date(year,month,Date.DaysInMonth(year,month))

                    vars("flr1") = "订单日期 >= #" & m1 & "# and 订单日期<= #" & m2 & "#"

                End If

            Else

                vars("flr1") = ""

            End If

        Case "TreeView2"

            If tv2.SelectedNode.Name <> "" And   left(tv2.SelectedNode.Name,2) <> "所有"

                If tv2.SelectedNode.Level = 0

                    vars("flr2") = "订单编号 = \'" & tv2.SelectedNode.Name & "\'"

                Else

                    vars("flr2")  = "订单编号 = \'" & tv2.SelectedNode.ParentNode. Name & "\' and 产品名称= \'" & tv2.SelectedNode.Name & "\'"

                End If

            Else

                vars("flr2")  = ""

            End If

        Case "TreeView3"

            If tv3.SelectedNode.Name <> "" And  left(tv3.SelectedNode.Name,2) <> "所有"

                If tv3.SelectedNode.Level = 0

                    vars("flr3")  = "生产工序 = \'" & tv3.SelectedNode.Name & "\'"

                Else

                    vars("flr3")  = "生产工序 = \'" & tv3.SelectedNode.ParentNode. Name & "\' and 生产组别= \'" & tv3.SelectedNode.Name & "\'"

                End If

            Else

                vars("flr3")  = ""

            End If

    End Select

    For i As Integer = 1 To 3

        If vars("flr" & i) > "" Then

            flr + = " And " & vars("flr" & i)

        End If

    Next

    If flr > "" Then

        flr = flr.SubString(5)

    Else

        flr = ""

    End If

    Tables("生产数据查询_Table1").Filter = flr

End If