Devexpress Gridview仅显示第一页数据，从第二页开始不显示数据

Question

我在devexpress网格视图数据显示中遇到问题。我通过c＃将数据插入到网格视图中，当我执行时，它仅显示数据的第一页，而当我单击第二页等等时，则不显示数据。

代码如下：

web.config

<connectionStrings>
<add name="cn" connectionString="data source=xx;initial catalog=xx;user id=xx;password=xx;" providerName="System.Data.SQLClient"/></connectionStrings>

webform.aspx

<dx:ASPxGridView ID="Grid" runat="server" CssClass="auto-style5" Width="888px" ></dx:ASPxGridView>

webform.aspx.cs

using System;
using System.Web.UI;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;

    public partial class WebForm1 : System.Web.UI.Page
    {

        DataTable dt = new DataTable();

        protected void Page_Load(object sender, EventArgs e)
        {
            if (!Page.IsPostBack)
            {
                ReadData();
            }  
        }

        public void ReadData()
        {
            try
            {
                using (SqlConnection cn = new SqlConnection(ConfigurationManager.ConnectionStrings["cn"].ConnectionString))
                {
                    if (cn.State == System.Data.ConnectionState.Closed)
                    {
                        cn.Open();
                    }
                    using(SqlDataAdapter da= new SqlDataAdapter("Select RULETYPE,RULENAME,seqNo,SUM(CNT) as CNT,SUM(WFS_QTY) as QTY,(Select SUM(WFS_QTY) from RANK_DECISIVE where EQPtype = 'IASCAN' and DATADATE = '2018/06/12') as TTL_QTY From(Select t1.EQPID, t1.RULETYPE, t1.RULENAME, t1.CNT, t1.WFS_QTY, isNull(t2.rankingIndex, 999) as seqNo from(select a.EQPID, a.RULETYPE, a.RULENAME, a.CNT, a.WFS_QTY, b.ruleName as reportName from RANK_DECISIVE a, station b where a.EQPtype = 'IASCAN' and a.DATADATE = '2018/06/12' and RULETYPE = 'HIGHWIP' and a.EQPID = b.StationName) t1 left join rankingRule t2 on t1.reportName = t2.ReportName and t1.RULETYPE = t2.ruleName and t1.RULENAME = t2.reason) t3 Group by RULETYPE, RULENAME, seqNo", cn))
                    {
                        //Grid.PageIndex = newPageIndex;
                        da.Fill(dt);
                        Grid.DataSource = dt;
                        Grid.DataBind();


                    }
                }
            }
            catch(Exception ex)
            {
                Response.Write(ex.Message);

            }
        }