1 　 /// <summary>
 2     /// 返回jsonp上下文
 3     /// </summary>
 4     public class JsonpResult : JsonResult
 5     {
 6         const string CALLBACKNAME = "callback";
 7         /// <summary>
 8         /// 复写渲染视图方法
 9         /// </summary>
10         /// <param name="context"></param>
11         public override void ExecuteResult(ControllerContext context)
12         {
13             if (context == null)
14             {
15                 throw new ArgumentNullException("当前请求上下文出错");
16             }
17             if ((JsonRequestBehavior == JsonRequestBehavior.DenyGet)
18                 && String.Equals(context.HttpContext.Request.HttpMethod, "GET"))
19             {
20                 throw new InvalidOperationException("Jsonp只能是ＧＥＴ请求");
21             }
22             var response = context.HttpContext.Response;
23             if (!String.IsNullOrEmpty(ContentType))
24             {
25                 response.ContentType = ContentType;
26             }
27             else
28             {
29                 response.ContentType = "application/json";
30             }
31             if (ContentEncoding != null)
32             {
33                 response.ContentEncoding = this.ContentEncoding;
34             }
35             if (Data != null)
36             {
37                 String buffer;
38                 var request = context.HttpContext.Request;
39                 var serializer = new JavaScriptSerializer();
40                 if (request[CALLBACKNAME] != null)
41                     buffer = String.Format("{0}({1})", request[CALLBACKNAME], serializer.Serialize(Data));
42                 else
43                     buffer = serializer.Serialize(Data);
44                 response.Write(buffer);
45             }
46         }
47     }

 1  　　　　/// <summary>
 2         /// 跨域ＡＰＩ
 3         /// </summary>
 4         /// <returns></returns>
 5         public JsonpResult GetUserAPI(string userID)
 6         {
 7             JsonpResult result = new JsonpResult()
 8             {
 9                 Data = new { name = "zzl", res = true, },
10                 JsonRequestBehavior = JsonRequestBehavior.AllowGet
11             };
12             return result;//反回一个callback(msg)对象
13         }

 1  //跨域调用公用的ＡＰＩ，如果希望它相应error事件，需要使用$.jsonp，而不是JQ的$.ajax
 2     function jsonpFun() {
 3         $.ajax({
 4             dataType: 'jsonp', //跨域使用它
 5             jsonp: 'callback', //可以省略，但如果显示声明它，必须是callback，因为在JsonResult里jsonp字符串已经被规定成它了
 6             url: 'http://www.jsonp.com/Common/GetUserAPI',
 7             data: { userID: 1 },
 8             type: 'GET',
 9             success: function (data) {
10                 alert(data.name);
11             },
12             error: function (data) {
13                 alert("获取用户信息失败");
14             }
15         });
16     }

 1       $.jsonp({
 2             url: 'http://www.jsonp.com/Common/GetUserAPI?userID=1',
 3             callbackParameter: 'callback',
 4             success: function (data) {
 5                 alert(data.name);
 6             },
 7             error: function (xOptions, textStatus) {
 8                 alert("获取用户信息失败");
 9             }
10         });

1 <script src="http://www.cnblogs.com/Scripts/jquery.jsonp-2.3.0.min.js" type="text/javascript"></script>