c# - 用于继承/类型区分的自定义模型绑定器

Question

抱歉，如果这个问题已经被问了一百万次，但我似乎无法在 Google 或 SO 上找到解决方案。

在 ASP.NET Core 中，是否可以编写自定义模型绑定器或类似的东西，这将允许我在 Web API 中获得一些继承支持？

基本上我有一个像这样的课程：

public class Order {
   public Guid Id { get; set; }
   public PaymentContainer PaymentParameters { get; set; }
}

还有一个容器类

public class PaymentContainer 
{
    public string Type { get; set; }

    public IPaymentParameters Value { get; set; }
}

以及一些实现IPaymentParameters接口的类，以及一个控制器方法，例如：

[HttpPost]
public IActionResult CreateOrder([FromBody]Order order)
{
}

我非常希望客户端能够发送 json，例如：

{
  "id" : "1234-..-1234",
  "paymentParameters" : {
      "type": "SpecialParameters1",
      "value" : { /* instance of specialparameters1 here */ }
  }
}

然后让“value”属性成为“SpecialParameters1”的一个实例，一旦它到达控制器方法。

我认为可以编写一个模型绑定器，但我不能完全理解它是如何完成的。

注意：我知道可以更改 Json.Net TypeNameHandling 的方法，但我宁愿不搞乱所有其他依赖 json 序列化程序的东西，而只需将其设置为 Auto 或 All 将开辟一些途径远程代码执行。

澄清：第一个答案后的小更新目标是有多个参数实例，这样以下输入也“有效”

{
  "id" : "1234-..-1234",
  "paymentParameters" : {
      "type": "SpecialParameters2",
      "value" : { /* instance of specialparameters2 here */ }
  }
}

当然我会上课

public class SpecialParameters1 : IPaymentParameters{}
public class SpecialParameters2 : IPaymentParameters{}

标签： c#asp.net-core

Answer 1

Yes, it ASP.NET Core is quite good at model binding, I will setup example for you (just had refactored a little your classes - not sure in details what you have to do, but as a demonstration of a principle I think it will suit well)

In View you setup something like this:

<h2>orders with ajax</h2>
<dl>
    <dt>Order Id:</dt>
    <dd id="order-id">D3BCDEEE-AE26-4B20-9170-D1CA01B52CD4</dd>

    <dt>Payment container - Type</dt>
    <dd id="order-paymentcontainer-type">Card payment</dd>

    <dt>Payment Parameters - Name</dt>
    <dd id="order-paymentcontainer-paymentParameters-name">Card payment nr. 1</dd>

    <dt>Payment Parameters - Provider</dt>
    <dd id="order-paymentcontainer-paymentParameters-provider">Big Bank</dd>
</dl>
<a id="submit-button">Process order</a>


@section Scripts {
    <script src="~/js/paymentTest.js"></script>
}

Then you setup classes:

public class Order
{
    public Guid Id { get; set; }
    public PaymentContainer PaymentContainer { get; set; }
}

public class PaymentContainer
{
    public string Type { get; set; }
    public PaymentParameters PaymentParameters { get; set; }
}

public class PaymentParameters
{
    public string Name { get; set; }
    public string Provider { get; set; }
}

Then write in your paymentTest.cs

var order = {
        Id: "",
        PaymentContainer: {
            Type: "",
            PaymentParameters: {
                Name: "",
                Provider: ""
            }
        }
    };

order.Id = document.getElementById("order-id").innerHTML;
order.PaymentContainer.Type = document.getElementById("order-paymentcontainer-type").innerHTML;
order.PaymentContainer.PaymentParameters.Name = document.getElementById("order-paymentcontainer-paymentParameters-name").innerHTML;
order.PaymentContainer.PaymentParameters.Provider = document.getElementById("order-paymentcontainer-paymentParameters-provider").innerHTML;

$("#submit-button").click(function () {
    $.ajax({
        url: 'api/orders',
        type: 'POST',
        dataType: "json",
        contentType: 'application/json',
        data: JSON.stringify(order),
        success: function (data) {
            location.reload();
        }
    });
});

And finally in controller setup method for binding

[Route("api/orders")]
[HttpPost]
public async Task ProcessOrder([FromBody] Order order)
{
    var orders = new List<Order>();
    orders.Add(order);

    // and some other code ...
}