Question

我的gridview有一个问题，我每次循环时都会追加到字符串的末尾，我尝试在再次循环之前删除附加（如下面的代码所示）但它似乎没有起作用：

Private Sub LoadData()

    conn = New SqlConnection(connectionString)
    ds = New DataSet("Accounts")
    da = New SqlDataAdapter("SELECT [branch], [no] , [surname], [name], [type], [sub], [totalAmount], loc, locstatus, HoldCalc, odTimes " & _
                            "FROM [DmdOD]", conn)

    conn.Open()

    da.FillSchema(ds, SchemaType.Source, "Accounts")
    da.Fill(ds, "Accounts")

    conn.Close()

    Dim loc As String
    Dim hold As String
    Dim holdString As String
    Dim odString As String

    Dim tblAccounts As DataTable
    tblAccounts = ds.Tables("Accounts")

    'Clone table in order to manipulate data
    Dim dtClone As DataTable = tblAccounts.Clone()
    dtClone.Columns("loc").DataType = System.Type.GetType("System.String")
    dtClone.Columns("odtimes").DataType = System.Type.GetType("System.String")
    dtClone.Columns("HoldCalc").DataType = System.Type.GetType("System.String")

    'Perform logic on fields before binding to gridview

    tblAccounts = DeleteDuplicateFromDataTable(tblAccounts, "no")

    For Each dr As DataRow In tblAccounts.Rows
        dtClone.ImportRow(dr)
        For Each drClone As DataRow In dtClone.Rows
            loc = drClone.Item("loc")
            odString = drClone.Item("odtimes")
            hold = drClone.Item("HoldCalc")
            If loc = "0.0000" Then
                loc = " "
                drClone.Item("loc") = loc
            End If

            'hold = CType(drClone.Item("HoldCalc"), Decimal)
            holdString = hold

            If loc <> "0.0000" AndAlso holdString < "0.0000" Then
                holdString &= " EX"
                drClone.Item("HoldCalc") = holdString
            ElseIf loc = "0.000" AndAlso hold < 0 Then
                holdString &= " OD"
                drClone.Item("HoldCalc") = holdString
            Else
                holdString = ""
                drClone.Item("HoldCalc") = holdString
            End If

            If odString = "0" Then
                odString = ""
                drClone.Item("odtimes") = odString
            End If

            If holdString.Length > 2 AndAlso (holdString.Contains(" EX EX") OrElse holdString.Contains(" OD OD")) Then
                drClone.Item("HoldCalc") = holdString.Substring(0, holdString.Length - 2)
            End If
        Next
    Next



    dtClone.AcceptChanges()


    GVAccounts.DataSource = dtClone
    GVAccounts.DataBind()

End Sub

每次循环时它只会附加到字符串的末尾，虽然如果符合条件，它会进入我的If语句，但我仍然会输出错误的结果。我想要的输出应该只有价格之后的EX或OD，而是它最后输出EX多次，我不希望这个....我希望这是有道理的。

无论如何，我对如何解决这个问题感到困惑，Google对此毫无帮助，我们将不胜感激。

Answer 1

很多时候它会附加很多次，因为你在克隆中循环遍历行很多次。

将tblAccounts行添加到dtClone之后，您遍历dtClone中的所有行，然后对新行及其前面的所有行执行操作，因此它是正常，你要多次附加字符串结束。

为什么不从tblAccounts克隆行，处理它然后将其添加到dtClone？

字符串在Gridview中无法正确显示

1 个答案: