为什么使用Ajax将参数传递给ASP.NET Core中的控制器始终为NULL？

Question

它可以工作，但是传递的参数始终为null，该代码在ASP.NET Framework（.Net Framework）上的其他项目中起作用，但在ASP.NET Core中不起作用。

var inputParams = "{namex: '" + 'testdata' + "'}";

var xhr = $.ajax({
    url: "/Test/MyFunction",
    type: 'POST',
    dataType: 'json',
    data: inputParams,
    contentType: 'application/json; charset=utf-8',
    success: function (msg) {

    },
    error: function (xhr) {

    }
});

测试控制器包含：

   [HttpPost]
   public JsonResult MyFunction(string namex) <--- namex is always NULL
    {
        return Json(false);
    }

Answer 1

将FromBodyAttribute添加到参数

MyFunction（[FromBody]字符串namex）

Answer 2

没有以正确的格式发送数据，以便内容正确绑定到操作

首先正确构造要发布的有效负载

var inputParams = { namex: "testdata" }; //<-- NOTE JavaScript

var xhr = $.ajax({
    url: "/Test/MyFunction",
    type: 'POST',
    dataType: 'json',
    data: JSON.stringify(inputParams), //<-- NOTE CONVERSION TO JSON
    contentType: 'application/json; charset=utf-8',
    success: function (msg) {

    },
    error: function (xhr) {

    }
});

下一步创建一个模型以将数据保存在服务器端

public class MyModel {
    public string namex { get; set;}
}

最后重构操作以绑定到请求正文中的预期数据

[HttpPost]
public IActionResult MyFunction([FromBody]MyModel model) {
    if(ModelState.IsValid) {
        string namex = model.namex;
        return Ok();
    }
    return BadRequest(ModelState);
}

参考Model Binding in ASP.NET Core

Answer 3

仅发送而没有对象

var inputParams = 'testdata';

var xhr = $.ajax({
    url: "/Test/MyFunction",
    type: 'POST',
    dataType: 'json',
    data: inputParams,
    contentType: 'application/json; charset=utf-8',
    success: function (msg) {

    },
    error: function (xhr) {

    }
});

---

或

---

var xhr = $.ajax({
    url: "/Test/MyFunction?namex=testdata", // <------ here
    type: 'POST',
    dataType: 'json',
    contentType: 'application/json; charset=utf-8',
    success: function (msg) {

    },
    error: function (xhr) {

    }
});