{"d":"[{\"ID\":\"6b2b8c62-31ce-4df2-982b-054ff5f6be72\",\"Name\":\"Carol\",\"Surname\":\"IrishWife\"},{\"ID\":\"d254740a-0a0f-4a1e-9e4f-0812227dd5af\",\"Name\":\"Willie\",\"Surname\":\"Le Roux\"},{\"ID\":\"660bf0dd-436a-4588-a9c0-19fd6fdcee23\",\"Name\":\"Emmas\",\"Surname\":\"Mum\"},{\"ID\":\"6b9403c5-b728-4e96-bcb1-203e7472eec3\",\"Name\":\"Owen\",\"Surname\":\"Lima\"},{\"ID\":\"d52c08fb-4418-4600-960f-243ff4443ee6\",\"Name\":\"Tim\",\"Surname\":\"Lee\"},{\"ID\":\"e2aacf5b-8855-44ce-9338-3d39f8ab3349\",\"Name\":\"Marcello\",\"Surname\":\"MT\"},{\"ID\":\"578be087-8385-46d6-89de-3db31d352cbc\",\"Name\":\"Carlyn\",\"Surname\":\"Homegroup\"},{\"ID\":\"4c805825-2bee-447a-8b75-41ead17db33e\",\"Name\":\"George\",{\"ID\":\"ae48804f-5e78-42c8-9ba0-4214c98a5a89\",\"Name\":\"Isla\",{\"ID\":\"f8be2f4f-fedb-4863-8a84-44fddea84ea9\",\"Name\":\"Peter\",\"Surname\":\"Anderson\"},{\"ID\":\"15e7644d-ec43-44ff-a959-47e00112da6b\",\"Name\":\"Kitty\",\"Surname\":\"Corbett\"},{\"ID\":\"8fd7fccc-335c-4d5c-93b5-4b00f96a9950\",\"Name\":\"Natalie\",\"Surname\":\"Archibald\"},{\"ID\":\"09b5aad2-2cf1-488a-962b-4d692b05ddea\",\"Name\":\"Miku\",\"Surname\":\"Heally\"},{\"ID\":\"affa369e-5af3-4537-a0f4-71422956da41\",\"Name\":\"Steven\",{\"ID\":\"65f57da3-4f88-4798-9590-83b4ccecfc44\",{\"ID\":\"53bfb451-f66f-4b6e-b430-8d13c95b30d8\",\"Name\":\"Philip\",{\"ID\":\"c7f22b9b-4030-4f82-9f75-bbb726cabb73\",\"Name\":\"Vincent\",\"Surname\":\"Van Der Walt\"},{\"ID\":\"232577be-3165-4316-a20d-c2f2a09c5382\",\"Name\":\"Scott\",\"Surname\":\"Lynn\"},{\"ID\":\"913508a1-5dca-4504-8caf-c8e3dc386fc0\",\"Name\":\"Dan\",{\"ID\":\"36054a07-b14d-4c1c-b35f-e00875dde7e5\",\"Name\":\"Sarah\",{\"ID\":\"f14e7d98-e040-4ba9-928f-f2ff48116b0b\",\"Name\":\"Josh\",\"Surname\":\"IrishDude\"}]"}

当我在fiddler的JSON视图中检查结果时，它显示以下JSON：

d=[{"ID":"6b2b8c62-31ce-4df2-982b-054ff5f6be72","Name":"Carol","Surname":"IrishWife"},{"ID":"d254740a-0a0f-4a1e-9e4f-0812227dd5af","Name":"Willie","Surname":"Le Roux"},{"ID":"660bf0dd-436a-4588-a9c0-19fd6fdcee23","Name":"Emmas","Surname":"Mum"},{"ID":"6b9403c5-b728-4e96-bcb1-203e7472eec3","Name":"Owen","Surname":"Lima"},{"ID":"d52c08fb-4418-4600-960f-243ff4443ee6","Name":"Tim","Surname":"Lee"},{"ID":"e2aacf5b-8855-44ce-9338-3d39f8ab3349","Name":"Marcello","Surname":"MT"},{"ID":"578be087-8385-46d6-89de-3db31d352cbc","Name":"Carlyn","Surname":"Homegroup"},{"ID":"4c805825-2bee-447a-8b75-41ead17db33e","Name":"George",{"ID":"ae48804f-5e78-42c8-9ba0-4214c98a5a89","Name":"Isla",{"ID":"f8be2f4f-fedb-4863-8a84-44fddea84ea9","Name":"Peter","Surname":"Anderson"},{"ID":"15e7644d-ec43-44ff-a959-47e00112da6b","Name":"Kitty","Surname":"Corbett"},{"ID":"8fd7fccc-335c-4d5c-93b5-4b00f96a9950","Name":"Natalie","Surname":"Archibald"},{"ID":"09b5aad2-2cf1-488a-962b-4d692b05ddea","Name":"Miku","Surname":"Heally"},{"ID":"affa369e-5af3-4537-a0f4-71422956da41","Name":"Steven",{"ID":"65f57da3-4f88-4798-9590-83b4ccecfc44",{"ID":"53bfb451-f66f-4b6e-b430-8d13c95b30d8","Name":"Philip",{"ID":"c7f22b9b-4030-4f82-9f75-bbb726cabb73","Name":"Vincent","Surname":"Van Der Walt"},{"ID":"232577be-3165-4316-a20d-c2f2a09c5382","Name":"Scott","Surname":"Lynn"},{"ID":"913508a1-5dca-4504-8caf-c8e3dc386fc0","Name":"Dan",{"ID":"36054a07-b14d-4c1c-b35f-e00875dde7e5","Name":"Sarah",{"ID":"f14e7d98-e040-4ba9-928f-f2ff48116b0b","Name":"Josh","Surname":"IrishDude"}]

所以fiddler可以解析成功，但在客户端上，jquery ajax错误回调函数显示以下错误：

Error: No conversion from text to application/json

wcf方法定义如下：

[OperationContract]
    [WebGet(ResponseFormat=WebMessageFormat.Json)]
    public string GetPeople(Guid groupId)
    {
        using (SchedulerContext context = new SchedulerContext())
        {
            JavaScriptSerializer ser = new JavaScriptSerializer();

            var query = from p in context.People
                        where p.Group_ID == groupId
                        select new
                        {
                            p.ID,p.Name,p.Surname
                        };

            return ser.Serialize(query.ToArray());
        }   
    }

最后，调用jquery是：

$.ajax(
        {
            type: "GET",dataType: "application/json",contentType: "json",data: { groupId: 'ae09a080-5d7c-4e92-9a87-591574b7c4b8' },url: "WebAPI.svc/GetPeople",error: function (jqXHR,textStatus,errorThrown) {
                alert("error");
            },success: function (msg) {
                alert(msg.d[0].Name);
            }
        }
);

提前致谢！

更新：
感谢@ user1370958，更接近解决方案。

将错误回调函数更改为以下内容时，会成功返回结果…

error: function (jqXHR,errorThrown) {
    var test = $.parseJSON(jqXHR.responseText);
    var test2 = $.parseJSON(test.d);
    alert(test2[0].Name);
},

不知道为什么，但我必须解析结果，然后解析嵌套的对象。我假设如果我的任何返回的类型包含复杂的对象，它也将需要另一个解析…