CORS 不适用于 jQuery

Question

我在 WCF RESTful 服务中有以下代码

public EmployeeJSON GetEmployeeJSON(string id)
    {
        List<EmployeeJSON> employees = new List<EmployeeJSON>()
        {
             new EmployeeJSON() {Name="Sumanth",Id=101,Salary=5000.00 },
             new EmployeeJSON() {Name="Ehsan",Id=102,Salary=6000.00 },
        };

        var Employee = (from x in employees
                        where x.Id.ToString() == id
                        select x);


        return Employee.FirstOrDefault() as EmployeeJSON;
    }

下面是RESTful Service的声明

[OperationContract]
[WebInvoke(Method = "GET", UriTemplate = "GetJson/{id}", ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.Wrapped)]
EmployeeJSON GetEmployeeJSON(string id);

当我在浏览器中执行以下 URL 时

http://localhost:1249/Service1.svc/GetJson/101

我得到如下结果

{"GetEmployeeJSONResult":{"Id":101,"Name":"Sumanth","Salary":5000}}

但是当我从 jQuery 调用时，代码会出错并显示空消息

$(document).ready(function () {
    });

    var GetJson = function () {
        $.ajax({
            type: "GET",
            url: "http://localhost:1249/Service1.svc/GetJson/101",
            contentType: "application/json;charset=utf-8",
            dataType: "json",
            success: function (data) {
                var result = data.GetEmployeeJSONResult;
                var id = result.Id;
                var name = result.Name;
                var salary = result.Salary;
                $('#jsonData').html('');
                $('#jsonData').append('<table border="1"><tr><th>Employee Id</th><th>Name</th><th>Salary</th></tr><tr><td>' + id + '</td><td>' + name + '</td><td>' + salary + '</td></tr></table>');

            },
            error: function (xhr) {
                alert(xhr.responseText);
            }
        });
    }

下面是代码，我放在WCF RESTful Service的web.config中

<system.webServer>
<httpProtocol>
  <customHeaders>
    <add name="Access-Control-Allow-Origin" value="*" />
  </customHeaders>
 </httpProtocol>
</system.webServer>

我在这里错过了什么？

Answer 1

通过将下一行代码添加到 Startup 类来配置您的 WEB API 以使用 CORS：

app.UseCors(CorsOptions.AllowAll);
var config = new HttpConfiguration();
var enableCors = new EnableCorsAttribute("*", "*", "*");
config.EnableCors(enableCors);

*其中app 是IAppBuilder 而config 是HttpConfiguration