首先我要说的是，您选择的方法不是最简单的。 ScriptMethods 很容易与 ASP.NET ScriptManager 一起使用，而不是与 jQuery 一起使用。我会建议你最好使用支持 JSON 的 WCF HTTP 服务（作为 RESTfull 服务更好），而不是你现在尝试使用的 ASMX Web 服务。
不过，无需在客户端使用任何 Microsoft 技术即可让您的代码正常工作。
首先验证服务器端。
- 将 webmethods.aspx 重命名为 webmethods.asmx。
-
验证您放置在 \ 的内部，并且配置中也存在 asmx 扩展的 httpHandlers (ScriptHandlerFactory)：
<configuration>
<!-- ... -->
<system.web>
<webServices>
<protocols>
<add name="HttpGet"/>
</protocols>
</webServices>
<httpHandlers>
<!-- ... -->
<add verb="*" path="*.asmx"
type="System.Web.Script.Services.ScriptHandlerFactory"
validate="false"/>
</httpHandlers></system.web></configuration>
-
验证为继承自 System.Web.Services.WebService 的类设置的 [ScriptService] 属性（如果您喜欢全名，则为 [System.Web.Script.Services.ScriptService]）。
李>
现在您可以测试服务了。在您的 Web 浏览器 URL 中打开，例如 http://localhost/webmethods.asmx/AjaxGet?id=li1234
如果您收到类似
<?xml version="1.0" encoding="utf-8" ?>
<string xmlns="http://tempuri.org/">li1234</string>
您可以确定您的维修部件工作正常。
备注： 独立于“ResponseFormat = System.Web.Script.Services.ResponseFormat.Json”属性，如果“Content-Type:application/json;”，则服务应答带有 XML 响应未在请求中设置。
现在我们将修复客户端代码。我希望我在下面的代码中放置的 cmets 能解释一切。
还有一点小评论。在代码的最后一部分，我调用了另一个“复杂”的 web 方法：
[WebMethod]
[ScriptMethod (UseHttpGet = true, ResponseFormat = ResponseFormat.Json)]
public OutputData AjaxGetMore (InputData input) {
return new OutputData () {
id = input.id,
message = "it's work!",
myInt = input.myInt+1
};
}
在哪里
public class OutputData {
public string id { get; set; }
public string message { get; set; }
public int myInt { get; set; }
}
public class InputData {
public string id { get; set; }
public int myInt { get; set; }
}
现在只有在某些地方使用 JSON 插件的 JavaScript 代码，如果有人愿意，可以用 Crockford 的 json2.js 替换它。
var id = "li1234";
// version 1 - works
var idAsJson = '"' + id + '"'; // string serializes in JSON format
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGet?id=" + idAsJson,
contentType: "application/json; charset=utf-8",
success: function(msg) {
alert(msg.d); // var msg = {d: "li1234"}
},
error: function(res, status) {
if (status ==="error") {
// errorMessage can be an object with 3 string properties: ExceptionType, Message and StackTrace
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
}
}
});
// version 2 with respect of JSON plugin
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGet?id=" + $.toJSON(id),
contentType: "application/json; charset=utf-8",
success: function(msg) {
alert(msg.d); // var msg = {d: "li1234"}
},
error: function(res, status) {
if (status ==="error") {
// errorMessage can be an object with 3 string properties: ExceptionType, Message and StackTrace
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
}
}
});
// version 3 where jQuery will construct URL for us
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGet",
data: {id: $.toJSON(id)},
dataType: "json",
contentType: "application/json; charset=utf-8",
success: function(msg) {
alert(msg.d); // var msg = {d: "li1234"}
},
error: function(res, status) {
if (status ==="error") {
// errorMessage can be an object with 3 string properties: ExceptionType, Message and StackTrace
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
}
}
});
// version 4. We set "Content-Type: application/json" about our data, but we use no
// not 'dataType: "json"' parameter. Then we have "Accept: */*" in the request
// instead of "Accept: application/json, text/javascript, */*" before.
// Everithing work OK like before.
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGet",
data: {id: $.toJSON(id)},
contentType: "application/json; charset=utf-8",
success: function(msg) {
alert(msg.d); // var msg = {d: "li1234"}
},
error: function(res, status) {
if (status ==="error") {
// errorMessage can be an object with 3 string properties: ExceptionType, Message and StackTrace
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
}
}
});
// version 5. If we don't place "Content-Type: application/json" in our reqest we
// receive back XML (!!!) response with "HTTP/1.1 200 OK" header and
// "Content-Type: text/xml; charset=utf-8" which will be placed.
// How one can read in
// http://weblogs.asp.net/scottgu/archive/2007/04/04/json-hijacking-and-how-asp-net-ajax-1-0-mitigates-these-attacks.aspx),
// ASP.NET AJAX will not make JSON serialized of response data for
// security reasons.
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGet",
data: {id: $.toJSON(id)},
dataType: "json",
//contentType: "application/json; charset=utf-8",
success: function(msg) {
alert(msg.d); // var msg = {d: "li1234"}
},
error: function (res, status, ex) {
// the code here will be works because of error in parsing server response
if (res.status !== 200) { // if not OK
// we receive exception in the next line, be
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
} else {
alert("status=" + status + "\nex=" + ex + "\nres.status=" + res.status + "\nres.statusText=" + res.statusText +
"\nres.responseText=" + res.responseText);
}
}
});
// version 6. Send more komplex data to/from the service
var myData = { id: "li1234", myInt: 100}
$.ajax({
type: "GET",
url: "/webmethods.asmx/AjaxGetMore",
data: {input:$.toJSON(myData)},
dataType: "json",
contentType: "application/json; charset=utf-8",
success: function(msg) {
// var msg = {__type: "Testportal.OutputData", id: "li1234", message: "it's work!", myInt:101}
alert("message=" + msg.d.message + ", id=" + msg.d.id + ", myInt=" + msg.d.myInt);
},
error: function(res, status) {
if (status ==="error") {
// errorMessage can be an object with 3 string properties: ExceptionType, Message and StackTrace
var errorMessage = $.parseJSON(res.responseText);
alert(errorMessage.Message);
}
}
});