Asp.net回调技术Callback学习笔记
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2024-02-22 07:58:10
.aspx:
<%@ page language="c#" autoeventwireup="true" codefile="default.aspx.cs...
.aspx:
<%@ 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>
[/code]
.aspx.cs
[code]
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):
<%@ 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="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
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:
<%@ 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>
[code]
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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