在 datagridview 上加载数据的更快方法？

Posted 2023-04-12

【中文标题】在 datagridview 上加载数据的更快方法？

【英文标题】：Faster way to load data on datagridview?

【发布时间】：2020-03-21 10:23:17

【问题描述】：

我想更快地加载数据，因为完成所有这些过程大约需要 2 分钟。我想要发生的是更快地加载它，有没有办法做到这一点？

每个 datagridview 我有将近 1k 数据，数据库处理大约需要 1-2 秒。

下面是我的代码

试试
            暗循环 As Integer = txt_Cycle.Text
            昏暗 cyclelast, cycle2last, cycle3last As Integer
            暗淡 rt = txt_Route.Text


            cyclelast = 周期 - 1
            cycle2last = cyclelast - 1
            cycle3last = cycle2last - 1

            '2个月
            使用命令作为新的 SqlCommand()
                command.Connection = conn

                将参数名称调暗为新列表（字符串）（dt_data.RowCount - 2）
                For i As Integer = 0 To dt_data.RowCount - 3
                    Dim parameterName As String = "@meter_num_" & i
                    暗淡meter_number As String = dt_data.Rows(i).Cells(3).Value
                    command.Parameters.AddWithValue(parameterName,meter_number)
                    参数名称。添加（参数名称）
                下一个

                command.CommandText = String.Format("SELECT * FROM customer WHERE cycle = @cycle2last and Meter_num IN (SELECT Meter_num FROM customer WHERE cycle = @cyclelast and rt = @rt and meter_num IN (0))
                AND Meter_num IN (SELECT Meter_num FROM customer WHERE cycle = @cycle AND rt = @rt AND Meter_num IN (0)) ORDER BY Client_Name ASC,meter_num ASC, MtrType ASC", String.Join(",", parameterNames))
                command.Parameters.AddWithValue("@cycle2last", cycle2last)
                command.Parameters.AddWithValue("@cyclelast", cyclelast)
                command.Parameters.AddWithValue("@cycle", 循环)
                command.Parameters.AddWithValue("@rt", rt)

                将 da 作为新的 SqlDataAdapter（命令）
                暗淡为新数据集
                da.Fill(ds, "客户")
                Compare_Reading.dt_last2month.DataSource = ds.Tables(0)
            结束使用

            '上个月
            使用命令作为新的 SqlCommand()
                command.Connection = conn

                将参数名称调暗为新列表（字符串）（dt_data.RowCount - 2）
                For i As Integer = 0 To dt_data.RowCount - 3
                    Dim parameterName As String = "@meter_num_" & i
                    暗淡meter_number As String = dt_data.Rows(i).Cells(3).Value
                    command.Parameters.AddWithValue(parameterName,meter_number)
                    参数名称。添加（参数名称）
                下一个

                command.CommandText = String.Format("SELECT * FROM customer WHERE cycle = @cyclelast and meter_num IN (SELECT meter_num FROM customer WHERE cycle = @cycle2last and rt = @rt and meter_num IN (0))
                AND Meter_num IN (SELECT Meter_num FROM customer WHERE cycle = @cycle AND rt = @rt AND Meter_num IN (0)) ORDER BY Client_Name ASC,meter_num ASC, MtrType ASC", String.Join(",", parameterNames))
                command.Parameters.AddWithValue("@cyclelast", cyclelast)
                command.Parameters.AddWithValue("@cycle2last", cycle2last)
                command.Parameters.AddWithValue("@cycle", 循环)
                command.Parameters.AddWithValue("@rt", rt)

                将 da 作为新的 SqlDataAdapter（命令）
                暗淡为新数据集
                da.Fill(ds, "客户")
                Compare_Reading.dt_lastmonth.DataSource = ds.Tables(0)
            结束使用
            '本月
            使用命令作为新的 SqlCommand()
                command.Connection = conn

                将参数名称调暗为新列表（字符串）（dt_data.RowCount - 2）
                For i As Integer = 0 To dt_data.RowCount - 3
                    Dim parameterName As String = "@meter_num_" & i
                    暗淡meter_number As String = dt_data.Rows(i).Cells(3).Value
                    command.Parameters.AddWithValue(parameterName,meter_number)
                    参数名称。添加（参数名称）
                下一个

                command.CommandText = String.Format("SELECT * FROM customer WHERE cycle = @cycle AND Meter_num IN (SELECT Meter_num FROM customer WHERE cycle = @cyclelast AND rt = @rt AND Meter_num IN (0))
                                    AND Meter_num IN (SELECT Meter_num FROM customer WHERE cycle = @cycle2last AND rt = @rt AND Meter_num IN (0)) ORDER BY Client_Name ASC,meter_num ASC, MtrType ASC", String.Join(",", parameterNames))
                command.Parameters.AddWithValue("@cycle", 循环)
                command.Parameters.AddWithValue("@cyclelast", cyclelast)
                command.Parameters.AddWithValue("@cycle2last", cycle2last)
                command.Parameters.AddWithValue("@rt", rt)

                将 da 作为新的 SqlDataAdapter（命令）
                暗淡为新数据集
                da.Fill(ds, "客户")
                Compare_Reading.dt_curmonth.DataSource = ds.Tables(0)
            结束使用
            我.Hide()



            Compare_Reading.computation()
            Compare_Reading.txt_Route.Text = txt_Route.Text
            Compare_Reading.txt_billday.Text = txt_BillDay.Text
            Compare_Reading.txt_itn.Text = txt_itn.Text
            Compare_Reading.nup_cycle.Value = txt_Cycle.Text
            '标题名称
            Compare_Reading.headername()
            Compare_Reading.Show()
        捕获 ex As SqlException
            MsgBox（例如消息，MsgBoxStyle.Critical，“SQL 错误”）
        抓住前任作为例外
            MsgBox（例如Message，MsgBoxStyle.Critical，“一般错误”）
            '结束尝试
            '抓住前任例外
            'MessageBox.Show(String.Format("Error: 0", ex.Message), "Error", MessageBoxButtons.OKCancel, MessageBoxIcon.Error)
        结束尝试

这是计算类

公共子计算()
        'Showmonth GridView
        For i As Integer = 0 To dt_curmonth.RowCount - 1
            dt_showmonth.Rows.Add(dt_curmonth.Rows(i).Cells(0).Value)



            dt_showmonth.Rows(i).Cells(1).Value = dt_curmonth.Rows(i).Cells(4).Value '行程
            dt_showmonth.Rows(i).Cells(2).Value = dt_curmonth.Rows(i).Cells(11).Value 'mtr num
            dt_showmonth.Rows(i).Cells(3).Value = dt_last2month.Rows(i).Cells(14).Value ' dec
            dt_showmonth.Rows(i).Cells(4).Value = dt_lastmonth.Rows(i).Cells(14).Value ' jan
            dt_showmonth.Rows(i).Cells(5).Value = dt_curmonth.Rows(i).Cells(14).Value ' 2 月
            'dt_showmonth.Rows(i).Cells(10).Value = dt_curmonth.Rows(i).Cells(11).Value 'mtr num
            dt_showmonth.Rows(i).Cells(10).Value = dt_curmonth.Rows(i).Cells(12).Value 'mtr 类型
            dt_showmonth.Rows(i).Cells(11).Value = dt_last2month.Rows(i).Cells(18).Value 'mtr ff
            dt_showmonth.Rows(i).Cells(12).Value = dt_lastmonth.Rows(i).Cells(18).Value 'mtr ff
            dt_showmonth.Rows(i).Cells(13).Value = dt_curmonth.Rows(i).Cells(18).Value 'mtr ff

            如果 dt_last2month.Rows(i).Cells(14).Value = 0 那么 'last2
                dt_showmonth.Rows(i).Cells(3).Value = dt_lastmonth.Rows(i).Cells(13).Value
            万一
            如果 dt_lastmonth.Rows(i).Cells(14).Value = 0 那么 'last
                dt_showmonth.Rows(i).Cells(4).Value = dt_curmonth.Rows(i).Cells(13).Value
            万一

            Dim month2nd As Integer = dt_showmonth.Rows(i).Cells(3).Value
            Dim month1st As Integer = dt_showmonth.Rows(i).Cells(4).Value
            Dim curmonth As Integer = dt_showmonth.Rows(i).Cells(5).Value
            Dim high20 As Double
            将差异变暗为整数
            将 diff1 调暗为整数
            Dim per20 As Double
            Dim less20 As Double

            差异 = 第 1 个月 - 第 2 个月
            diff1 = curmonth - month1st
            per20 = 差异 * 0.3
            high20 = Math.Round((diff + per20), 2)
            less20 = Math.Round((diff - per20), 2)

            dt_showmonth.Rows(i).Cells(6).Value = diff
            dt_showmonth.Rows(i).Cells(7).Value = diff1
            dt_showmonth.Rows(i).Cells(8).Value = less20
            dt_showmonth.Rows(i).Cells(9).Value = high20


        下一个
    结束子

【问题讨论】：

你要拉回多少行？数据库检索需要多长时间？本地计算需要多长时间？将页面数据传输到客户端需要多长时间？

整个过程大约需要 2 分钟

我知道，但是您必须对每个部分进行计时才能知道哪个部分需要改进。因此，我们需要知道所有这些单独的时间。

您可以使用 3 个 select 语句进行 1 个 db 调用，并以更少的代码在一个数据集中加载 3 个表

使用服务器端分页实现显示数据。没有人会对在屏幕上一次看到 1000 行感兴趣。

【参考方案1】：

缓慢是由于在计算过程中更新 UI 的 datagridview。您不应该为数据绑定网格编辑 DataGridView 的 .Cells 属性。除此之外，单击列标题以按该列排序会造成严重破坏。

首先在内存中进行所有计算，并在所有计算完成后在最后设置 DataSource。这样 DataGridView 只会渲染一次屏幕。