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Asp.net回调技术Callback学习
.aspx:
Html代码
- <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head runat="server">
- <title>无标题页</title>
- <script type="text/javascript">
- //向服务器传递参数
- function DoSearch(){
- var firstName=document.getElementById("TextBox1").value;
- CallServer(firstName,"");
- }
- //得到服务器的数据
- function ReceiveServerData(txtUserInfo){
- Results.innerHTML=txtUserInfo;
- }
- //设置每1秒执行一次
- setInterval("DoSearch()",1000);
- </script>
- </head>
- <body>
- <form id="form1" runat="server">
- <div>
- 姓名:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
- <br />
- <span id="Results" style=" width:500px;"></span>
- </div>
- </form>
- </body>
- </html>
.aspx.cs
C#代码
- using System;
- using System.Collections;
- using System.Configuration;
- using System.Data;
- using System.Web;
- using System.Web.Security;
- using System.Web.UI;
- using System.Web.UI.HtmlControls;
- using System.Web.UI.WebControls;
- using System.Web.UI.WebControls.WebParts;
- using System.Data.SqlClient;
- public partial class _Default : System.Web.UI.Page, ICallbackEventHandler
- {
- protected string txtUserInfo;
- protected void Page_Load(object sender, EventArgs e)
- {
- //获取一个对客户端函数的引用
- string cbReference = Page.ClientScript.GetCallbackEventReference(this, "arg", "ReceiveServerData", "context");
- //动态注册回调函数
- string callbackScript = "function CallServer(arg,context)" + "{" + cbReference + "};";
- //引发callbackScript
- Page.ClientScript.RegisterStartupScript(this.GetType(), "CallServer", callbackScript, true);
- }
- //引发Callback事件处理
- public void RaiseCallbackEvent(string txtFirstName)
- {
- if (txtFirstName != null)
- {
- String connString = System.Configuration.ConfigurationManager.ConnectionStrings["sqlserver2008"].ToString();
- SqlConnection conn = new SqlConnection(connString);
- conn.Open();
- SqlCommand comm = new SqlCommand("select * from zzx where [name]=@name", conn);
- comm.Parameters.Add("@name", SqlDbType.VarChar).Value = txtFirstName;
- SqlDataReader reader = comm.ExecuteReader(CommandBehavior.CloseConnection);
- if (reader.Read())
- {
- txtUserInfo = "员工编号:" + reader["id"].ToString() + "<br>";
- txtUserInfo += "员工姓名:" + reader["name"].ToString() + "<br>";
- txtUserInfo += "地址:" + reader["address"].ToString() + "<br>";
- txtUserInfo += "服务器查询时间:" + DateTime.Now.ToString();
- }
- else
- {
- if (string.IsNullOrEmpty(txtFirstName))
- {
- txtUserInfo = "请输入姓名";
- }
- else
- {
- txtUserInfo = "查无此人";
- }
- }
- comm.Dispose();
- reader.Dispose();
- conn.Dispose();
- }
- }
- //得到回调的结果,返回给客户端
- public string GetCallbackResult()
- {
- return txtUserInfo;
- }
- }
简化版(偷懒一下):
Html代码
- <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head runat="server">
- <title>无标题页</title>
- <script type="text/javascript">
- function OnCallBack(txtUserInfo,context){
- Results.innerHTML=txtUserInfo;
- }
- </script>
- </head>
- <body>
- <form id="form1" runat="server">
- <div>
- 姓名:<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
- <input id="Button2" type="button" value=http://www.mamicode.com/"button"
- onclick="<%=Page.ClientScript.GetCallbackEventReference(this, "document.getElementById(‘TextBox1‘).value", "OnCallBack",null)%>" />
- <br />
- <span id="Results" style="pink; width: 500;"></span>
- </div>
- </form>
- </body>
- </html>
.aspx.cs
C#代码
- using System;
- using System.Collections;
- using System.Configuration;
- using System.Data;
- using System.Web;
- using System.Web.Security;
- using System.Web.UI;
- using System.Web.UI.HtmlControls;
- using System.Web.UI.WebControls;
- using System.Web.UI.WebControls.WebParts;
- using System.Data.SqlClient;
- using System.Text;
- public partial class _Default : System.Web.UI.Page, ICallbackEventHandler
- {
- protected StringBuilder txtUserInfo;
- protected void Page_Load(object sender, EventArgs e)
- {
- }
- public string GetCallbackResult()
- {
- return txtUserInfo.ToString();
- }
- public void RaiseCallbackEvent(string txtFirstName)
- {
- txtUserInfo = new StringBuilder();
- String connString = ConfigurationManager.ConnectionStrings["sqlserver2008"].ToString();
- SqlConnection conn = new SqlConnection(connString);
- conn.Open();
- SqlCommand comm = new SqlCommand("select * from zzx where [name]=@name", conn);
- comm.Parameters.Add("@name", SqlDbType.VarChar).Value = txtFirstName;
- SqlDataReader reader = comm.ExecuteReader(CommandBehavior.CloseConnection);
- if (reader.Read())
- {
- txtUserInfo.Append("员工编号:" + reader["id"].ToString() + "<br>");
- txtUserInfo.Append("员工姓名:" + reader["name"].ToString() + "<br>");
- txtUserInfo.Append("地址:" + reader["address"].ToString() + "<br>");
- txtUserInfo.Append("查询时间:" + DateTime.Now.ToString());
- }
- else
- {
- if (txtFirstName == string.Empty)
- {
- txtUserInfo.Append("请输入姓名");
- }
- else
- {
- txtUserInfo.Append("查无此人");
- }
- reader.Dispose();
- comm.Dispose();
- conn.Dispose();
- }
- }
- }
示例3:
Html代码
- <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default3.aspx.cs" Inherits="Default3" %>
- <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
- <html xmlns="http://www.w3.org/1999/xhtml">
- <head runat="server">
- <title>无标题页</title>
- <script type="text/javascript">
- //客户端执行的方法
- //下面的方法是接收并处理服务器方法返回的结果
- function Success(args,context){
- message.innerHTML=args;
- }
- //下面的方式是当接收服务器方法处理的结果发生异常时调用的方法
- function Error(){
- message.innerHTML="发生了异常!";
- }
- </script>
- </head>
- <body>
- <form id="form1" runat="server">
- <div>
- 用户名:<input type="text" id="txtUserName" onblur="CallServerMethod(txtUserName.value,null)" />
- <span id="message"></span>
- <br />
- 密码:<input type="password" size="10" maxlength="20" id="txtPwd" />
- </div>
- </form>
- </body>
- </html>
C#代码
- public partial class Default3 : System.Web.UI.Page,ICallbackEventHandler //实现ICallbackEventHandler接口
- {
- String result = String.Empty;
- protected void Page_Load(object sender, EventArgs e)
- {
- //获取当前页的ClientScriptManager的引用
- ClientScriptManager csm = Page.ClientScript;
- /*获取回调的引用.会在客户端生成WebForm_DoCallback方法,
- * 调用它来达到异步调用.这个方法是微软写的方法,会被发送
- 到客户端*/
- /*注意这里的"Success"和Error两个字符串分别是客户端代码中
- *定义的两个javascript函数*/
- //下面的方法最后一个参数的意义:true表示执行异步回调,false标志执行同步回调
- String reference = csm.GetCallbackEventReference(this, "args", "Success", "", "Error", true);
- String callbackScript = "function CallServerMethod(args,context){\n"+
- reference+";\n }";
- //向当前页面注册javascript脚本代码
- csm.RegisterClientScriptBlock(this.GetType(), "CallServerMethod",callbackScript,true);
- }
- #region ICallbackEventHandler 成员
- /// <summary>
- /// 返回回调方法执行结果的方法
- /// </summary>
- public string GetCallbackResult()
- {
- return result;
- }
- /// <summary>
- /// 在服务器端运行回调方法
- /// </summary>
- public void RaiseCallbackEvent(string eventArgument)
- {
- if (eventArgument.ToLower().IndexOf("admin")!=-1)
- {
- result =eventArgument+ "不能作为用户注册.";
- }
- else
- {
- result = eventArgument + "可以注册.";
- }
- }
- #endregion
- }
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