เตือน rows is not a member of devexpress.xtragrid.gridcontrol

Private Sub nbi_disability_LinkClicked(sender As Object, e As DevExpress.XtraNavBar.NavBarLinkEventArgs) Handles nbi_disability.LinkClicked
        Dim contxt As String = "c:\ProgramData\sn_tool.txt"
        'อ่านค่าใน sn_tool.txt เพิ่อเอาค่ามาแสดงใน textbox
        Dim line() As String = IO.File.ReadAllLines(contxt)
        Dim host As String = line(0)
        Dim user As String = line(1)
        Dim pwd As String = line(2)
        Dim db As String = line(3)
        Dim con As MySqlConnection = New MySqlConnection()
        con.ConnectionString = String.Format("server={0}; user id={1}; password={2}; database={3}; pooling=false", host, user, pwd, db)
        sql = "select hoscode,d315,count(b210) as b210,count(d310) as d310,count(d315) as d315,count(d330) as d330,count(d335) as d335 " & _
              "from person_deform_head pdh " & _
              "group by pdh.hoscode,pdh.b210,pdh.d315  "

        command = New MySqlCommand(sql, con)
        con.Open()
        command.Connection = con
        'MsgBox("Successfully connected!", MsgBoxStyle.Information)
        adapter = New MySqlDataAdapter(command)
        datast = New DataSet()
        adapter.Fill(datast, "ph")

        gc1.DataSource = datast.Tables("ph")

        
        
        sql = "SELECT count(b210) FROM person_deform_head "
        command = New MySqlCommand(sql, con)
        Dim b210 As Integer = command.ExecuteScalar()

        sql = "SELECT count(d310) FROM person_deform_head "
        command = New MySqlCommand(sql, con)
        Dim d310 As Integer = command.ExecuteScalar()


        gc1.rows.Add(New String() {b210, d310}) '--เพิ่มรายการที่ละแถว

    End Sub