Asp.net POST 参数始终为空

Question

为了传递电子邮件地址，我使用 Ajax 并以 POST 作为类型。

$.ajax({
    url: "api/Search/UserByEmail",
    type: "POST",
    data: JSON.stringify({ emailAddress: userEmail }),
    contentType: "application/json;charset=utf-8",
    dataType: "json",
    success: function (data) { ... }
});

Controller :

[HttpPost]
public IEnumerable<Object> UserByEmail([FromBody] string emailAddress) { ... }

Fiddler 是这么说的:

POST http://localhost:52498/api/Search/UserByEmail HTTP/1.1
Accept: application/json, text/javascript, */*; q=0.01
Content-Type: application/json;charset=utf-8
X-Requested-With: XMLHttpRequest
Referer: http://localhost:52498/#
Accept-Language: de-DE
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/5.0 (compatible; MSIE 10.0; Windows NT 6.1; WOW64; Trident/6.0)
Host: localhost:52498
Content-Length: 35
DNT: 1
Connection: Keep-Alive
Pragma: no-cache

{"emailAddress":"mail@example.com"}

为什么 emailAddress 参数始终为空？

Answer 1

 // JS - jQuery 
 $.ajax({
        url: "/Home/UserByEmail",
        type: "POST",
        data: { emailAddress: "joe@gmail.com" },
        dataType: "json",
        success: function (data) { if(data != null) { alert(data.toString()); } }
    });



  [Serializable]
  public class EmailFormModel {
     public string emailAddress { get; set; }
  }

    [HttpPost]
    public JsonResult UserByEmail(EmailFormModel emailFormModel)
    {
        bool ok = emailFormModel.emailAddress != null;
        return Json(new { ok }); 
    }

使用 formModel 并在类上放置一个可序列化的属性，它将序列化您的 javascript 自动转换为 C# 等效项。而且您不需要使用 Json-stringify。

注意删除了//contentType: "application/json;charset=utf-8",来自 ajax 方法的声明。我其实从来没有用过它。