reportview 数据更新的问题

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Configuration;
using Microsoft.Reporting.WinForms;
using System.Management;namespace WindowsApplication2
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }        private void Form1_Load(object sender, EventArgs e)
        {
            // TODO: 这行代码将数据加载到表“Database1DataSet1.Message”中。您可以根据需要移动或移除它。
            this.MessageTableAdapter.Fill(this.Database1DataSet1.Message);
            ReportDataSource myRD = new ReportDataSource("Database1DataSet1_Message", LoadMessageData());
            this.reportViewer1.LocalReport.DataSources.Add(myRD);
            this.reportViewer1.RefreshReport();
        }
        public DataTable LoadMessageData()
        {
                string strcon = ConfigurationManager.ConnectionStrings["WindowsApplication2.Properties.Settings.Database1ConnectionString"].ToString();
                SqlConnection sqlCon = new SqlConnection(strcon);
                DataSet myds = new DataSet();
                sqlCon.Open();
                string strCOM = "select * from Message";
                SqlDataAdapter myAdapter = new SqlDataAdapter(strCOM, sqlCon);
                myAdapter.Fill(myds, "Message");
                return myds.Tables[0];
        }        private void button1_Click(object sender, EventArgs e)
        {
            this.reportViewer1.LocalReport.DataSources.RemoveAt(0);
            Database1DataSet1.Message.Clear();
            ReportDataSource myRD = new ReportDataSource("Database1DataSet1_Message", LoadMessageData());
            this.reportViewer1.LocalReport.DataSources.Add(myRD);
            this.reportViewer1.RefreshReport();
        }
    }
}
启动了form读了200条消息  我在后台通过sql 加了10条信息
为什么我按下button1 reprotview1里面的数据不更新还是显示那200条 ？