下面的代码在加载窗口事件中耗时9.89秒,怎么回事?外部数据是放在区域网中,请教老师

Dim st As Date = Date.Now \'将开始时间保存在变量st中
Tables("提取客户资料_Table1").DataTable.SysStyles("EmptyArea").BackColor = Color.White
Tables("提取客户资料_Table1").DataTable.Fill("Select [客户姓名],[省份],[地区],[联系电话] From {客户资料} ","数据库", True)
Tables("提取客户资料_Table1").SetColVisibleWidth("客户姓名|100|省份|50|地区|100|联系电话|200")
For Each r As Row In Tables("提取客户资料_Table1")
    Dim cmd As New SQLCommand
    Dim dt As DataTable
    cmd.C
    cmd.CommandText = "SELECT * From {客户短信电话} Where [客户姓名] = \'" & r("客户姓名") & "\'"
    dt = cmd.ExecuteReader
    If dt.DataRows.Count > 0 Then
        r.Checked = True
    End If
Next

e.Form.Controls("Label1").Text = "耗时: " & (Date.Now - st).TotalSeconds & "秒"

反正是查询表,这样更好:

Dim SQL As string

Dim t1 As Table = Tables("提取客户资料_Table1")

SQL = "Select a.客户姓名,a.省份,a.地区,a.联系电话,b.客户短信电话  From {客户资料} a "

SQL+ = "INNER JOIN {客户短信电话} b ON a.客户姓名 = b.客户姓名"

t1.redraw = 0
t1.DataTable.SysStyles("EmptyArea").BackColor = Color.White
t1.Fill(SQL,"数据库", True)
t1.SetColVisibleWidth("客户姓名|100|省份|50|地区|100|联系电话|200")

Dim drs As List(of Dadtarow) = t1.DataTable.Select("客户短信电话 > \'\'")

For Each dr As DaRow In drs

      t1.Rows(t1.FindRow(dr)).Checked = -1

Next

t1.redraw = 1