"您请求的报表需要更多信息"问题

Question

<connectionStrings>
<add name="NorthwindConnectionString" connectionString="Data Source=(Local);Initial Catalog=Northwind;User ID=sa" providerName="System.Data.SqlClient"/>
</connectionStrings>
为DataSet1.xsd在Web.Config中添加的连接信息生成报表视图代码如下：
protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            using (SqlConnection db_Conn = new SqlConnection())
            {
                string sql = "select * from Customers";
                db_Conn.ConnectionString = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
                db_Conn.Open();
                SqlDataAdapter sda = new SqlDataAdapter(sql, db_Conn);
                DataSet ds = new DataSet();
                sda.Fill(ds, "Customers");                CrystalReportSource1.ReportDocument.Load(Server.MapPath("./CrystalReport.rpt"));
                CrystalReportSource1.ReportDocument.SetDataSource(ds.Tables["Customers"]);
                CrystalReportSource1.DataBind();
                CrystalReportViewer1.ReportSource = CrystalReportSource1;
                CrystalReportViewer1.DataBind();
            }
        }    }
可是只要一过几分钟，你再发出请求，就会出现“您请求的报表需要更多信息”，网上好多讲法，都没有解决，因为客户不怎么懂电脑，他们可能一打开了报表好长时间都不动电脑，再提交时，就会出现上面提示。（VS2005）

Answer 1

去掉 if (!Page.IsPostBack) 
        {