javascript 调用后台方法

来自：http://blog.youkuaiyun.com/hellojimmy520/article/details/7242725

方法一：直接使用<%=%>调用

前台JS：

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1. <script type="text/javascript"> 
2.        var methodStr = "<%=BehindMethod() %>"; 
3.        alert(methodStr); 
4.        </script> 

 <script type="text/javascript">
        var methodStr = "<%=BehindMethod() %>";
        alert(methodStr);
        </script>

后头方法：

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1. public static string BehindMethod() 
2.         { 
3.             return "这是一个后台的方法"; 
4.         } 

public static string BehindMethod()
        {
            return "这是一个后台的方法";
        }

方法二：用ajax调用

前台js:

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1. <script type="text/javascript" src="js/jquery-1.4.3.min.js"></script> 
2. <script type="text/javascript">  
3. var params = '{ext:"p9hp"}';  //参数，注意参数名要注意和后台方法参数名要一致         
4.         $(function(){ 
5.            $("#btnOk").click(function(){ 
6.             $.ajax({ 
7.                 type:"POST",  //请求方式 
8.                 url:"AjaxDemo.aspx/GetImg",  //请求路径：页面/方法名字 
9.                 data: params,     //参数 
10.                 dataType:"text",   
11.                 contentType:"application/json; charset=utf-8", 
12.                 beforeSend:function(XMLHttpRequest){   
13.                     $("#tips").text("开始调用后头方法获取图片路径,请等待"); 
14.                     $("#imgFood").attr("src","image/loading.gif"); 
15.                 }, 
16.                 success:function(msg){  //成功 
17.                     $("#imgFood").attr("src",eval("("+msg+")").d);   
18.                     $("#tips").text("调用方法结束"); 
19.                 }, 
20.                 error:function(obj, msg, e){   //异常 
21.                     alert("OH,NO"); 
22.                 }                
23.             }); 
24.         }); 
25.         }); 
26. </script> 

<script type="text/javascript" src="js/jquery-1.4.3.min.js"></script>
 <script type="text/javascript"> 
var params = '{ext:"p9hp"}';  //参数，注意参数名要注意和后台方法参数名要一致        
        $(function(){
           $("#btnOk").click(function(){
            $.ajax({
                type:"POST",  //请求方式
                url:"AjaxDemo.aspx/GetImg",  //请求路径：页面/方法名字
                data: params,     //参数
                dataType:"text",  
                contentType:"application/json; charset=utf-8",
                beforeSend:function(XMLHttpRequest){  
                    $("#tips").text("开始调用后头方法获取图片路径,请等待");
                    $("#imgFood").attr("src","image/loading.gif");
                },
                success:function(msg){  //成功
                    $("#imgFood").attr("src",eval("("+msg+")").d);  
                    $("#tips").text("调用方法结束");
                },
                error:function(obj, msg, e){   //异常
                    alert("OH,NO");
                }               
            });
        });
        });
</script>

页面html:

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1. <body> 
2.     <form id="form1" runat="server"> 
3.     <div> 
4.     <label id="tips"></label> 
5.        <img id="imgFood" /> 
6.        <input value="点击我，给你看一张图片" type="button" width="35px" id="btnOk"  /> 
7.         
8.     </div> 
9.     </form> 
10. </body> 

<body>
    <form id="form1" runat="server">
    <div>
    <label id="tips"></label>
       <img id="imgFood" />
       <input value="点击我，给你看一张图片" type="button" width="35px" id="btnOk"  />
       
    </div>
    </form>
</body>

后台方法：

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1. [System.Web.Services.WebMethod] 
2.       public static string GetImg(string ext) 
3.       { 
4.           System.Threading.Thread.Sleep(5000);//为了有点等待的效果，延迟5秒 
5.           StringComparer sc = StringComparer.OrdinalIgnoreCase; 
6.           string[] extArr = new string[] { "php", "asp", "aspx", "txt", "bmp" }; 
7.           bool f = extArr.Any(s=>sc.Equals(s,ext));   //判断传入的后缀名是否存在 
8.            
9.           if (f) 
10.           { 
11.               return "image/54222860.jpg"; 
12.           } 
13.           return "image/star1.jpg"; 
14.       } 

  [System.Web.Services.WebMethod]
        public static string GetImg(string ext)
        {
            System.Threading.Thread.Sleep(5000);//为了有点等待的效果，延迟5秒
            StringComparer sc = StringComparer.OrdinalIgnoreCase;
            string[] extArr = new string[] { "php", "asp", "aspx", "txt", "bmp" };
            bool f = extArr.Any(s=>sc.Equals(s,ext));   //判断传入的后缀名是否存在
            
            if (f)
            {
                return "image/54222860.jpg";
            }
            return "image/star1.jpg";
        }

 

方法三：AjaxPro (也是ajax)

第一步：下载AjaxPro.dll(或者AjaxPro.2.dll),并且添加引用到项目

第二步：修改配置文件web.config  

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1. <system.web> 
2. <httpHandlers> 
3.       <!--注册ajaxPro.2--> 
4.       <add verb="*" path="*.ashx" type="AjaxPro.AjaxHandlerFactory,AjaxPro.2"/> 
5.     </httpHandlers> 
6.   </system.web> 

<system.web>
<httpHandlers>
      <!--注册ajaxPro.2-->
      <add verb="*" path="*.ashx" type="AjaxPro.AjaxHandlerFactory,AjaxPro.2"/>
    </httpHandlers>
  </system.web>

第三步：对AjaxPro在页Page_Load事件中进行运行时注册。如：

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1. protected void Page_Load(object sender, EventArgs e) 
2. { 
3.     AjaxPro.Utility.RegisterTypeForAjax(typeof(AjaxDemo));  //注册 
4. } 

        protected void Page_Load(object sender, EventArgs e)
        {
            AjaxPro.Utility.RegisterTypeForAjax(typeof(AjaxDemo));  //注册
        }

第四步：创建服务器方法，并且用[AjaxPro.AjaxMethod]标注

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1. [AjaxPro.AjaxMethod] 
2. public string GetImgByAjaxPro() 
3. { 
4.     return "image/54222860.jpg"; 
5. } 

        [AjaxPro.AjaxMethod]
        public string GetImgByAjaxPro()
        {
            return "image/54222860.jpg";
        }

第五步：前台JS的调用：

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1. function GetMethodByAjaxPro() { 
2.            var a = JustTest.AjaxDemo.GetImgByAjaxPro();//JustTest是当前的名字空间，AjaxDemo表示后台类 
3.            document.getElementById("imgAjaxPro").src = a.value; 
4.        }