在asp.net中,有时候页面加载时,后台需要进行一些操作,比如查询数据库等。而且可能这些操作需要花费较长时间,致使前台长时间无响应,甚至有可能造成页面超时。可以采用以下方法解决:
1、asp.net 1.1
2、asp.net 2.0
在asp.net2.0的代码中采用了异步页,实现效率提高了。但是有一点不明白,一定要循环3次以上(while(i<3))前台才会显示“正在读取数据请稍候...”.
1、asp.net 1.1
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using System.Web.UI;
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using System.Web.UI.WebControls;
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using System.Web.UI.WebControls.WebParts;
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using System.Web.UI.HtmlControls;
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using System.Threading;
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public partial class Default2 : System.Web.UI.Page
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{
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private int vlue = 0;
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protected void Page_Load(object sender, EventArgs e)
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{
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Thread td = new Thread(new ThreadStart(BindData));
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td.Start();
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WritePress();
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//BindData();
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}
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private void WritePress()
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{
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int i = 0;
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while (vlue == 0)
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{
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Response.Write("<table id='s" + i + "' width='100%'><tr ><td></td><td align=center >正在读取数据请稍候
.</td></tr></table>");
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if (i > 0)
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{
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Response.Write("<script>document.getElementById('s" + (i - 1) + "').style.display ='none';</script>");
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}
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i = i + 1;
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Response.Flush();
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}
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Response.Write("<script>document.getElementById('s" + (i - 1) + "').style.display ='none';</script>");
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}
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public void BindData()
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{
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dsOrders DSO = new dsOrders();
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DSO.Orders.AddOrdersRow("zp", "1", DateTime.Now, DateTime.Now, DateTime.Now, "s", "t", "sz");
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GridView1.DataSource = DSO;
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GridView1.DataBind();
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Thread.Sleep(700);
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vlue = 1;
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}
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}
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2、asp.net 2.0
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using System;
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using System.Data;
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using System.Configuration;
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using System.Web;
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using System.Web.Security;
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using System.Web.UI;
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using System.Web.UI.WebControls;
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using System.Web.UI.WebControls.WebParts;
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using System.Web.UI.HtmlControls;
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using System.Threading;
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public partial class _Default : System.Web.UI.Page
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{
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private AsyncDelegateGetDataSet dgs;
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private int i = 0;
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protected void Page_Load(object sender, EventArgs e)
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{
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PageAsyncTask task = new PageAsyncTask(
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new BeginEventHandler(BeginAsyncOperation),
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new EndEventHandler(EndAsyncOperation),
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new EndEventHandler(TimeoutAsyncOperation),
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null
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);
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RegisterAsyncTask(task);
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WritePress();
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}
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public void BindData()
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{
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dsOrders DSO = new dsOrders();
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DSO.Orders.AddOrdersRow("zp", "1", DateTime.Now, DateTime.Now, DateTime.Now, "s", "t", "sz");
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GridView1.DataSource = DSO;
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GridView1.DataBind();
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Thread.Sleep(3000);
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}
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IAsyncResult BeginAsyncOperation(object sender, EventArgs e,
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AsyncCallback cb, object state)
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{
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dgs=new AsyncDelegateGetDataSet(BindData);
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return dgs.BeginInvoke(cb, state);
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}
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void EndAsyncOperation(IAsyncResult ar)
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{
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Response.Write("<script>document.getElementById('s" + (i - 1) + "').style.display ='none';</script>");
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dgs.EndInvoke(ar);
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}
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void TimeoutAsyncOperation(IAsyncResult ar)
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{ }
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private void WritePress()
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{
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while (i<3)
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{
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Response.Write("<table id='s" + i + "' width='100%'><tr ><td></td><td align=center >正在读取数据请稍候
.</td></tr></table>");
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if (i > 0)
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{
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Response.Write("<script>document.getElementById('s" + (i - 1) + "').style.display ='none';</script>");
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}
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i = i + 1;
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Response.Flush();
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}
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}
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}
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public delegate void AsyncDelegateGetDataSet();
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在asp.net2.0的代码中采用了异步页,实现效率提高了。但是有一点不明白,一定要循环3次以上(while(i<3))前台才会显示“正在读取数据请稍候...”.