C# 如何在模型绑定期间自动设置增量属性

我有一个ASP.NET核心MVC应用程序的输入请求主体，我将其绑定到C中的请求模型

public class Request 
{
    public int Index {get;set;}
    public string DocType {get;set;}
    public string DocId {get;set;}
}

这是我的请求

{
"request" : [
    {
        "DocType" : "MSWORD",
        "DocId"   : "553ed6c232da426681b7c45c65131d33"
    },
    {
        "DocType" : "MSEXCEL",
        "DocId"   : "256ed6c232da426681b7c45c651317895"
    }]
}

我想把这个请求映射到我的C模型，这样索引属性就会自动递增

换句话说，当我将我的C请求反序列化为JSON字符串时，它应该是这样的

{
"request" : [
    {
        "Index"   : 0,
        "DocType" : "MSWORD",
        "DocId"   : "553ed6c232da426681b7c45c65131d33"
    },
    {
        "Index"   : 1,
        "DocType" : "MSEXCEL",
        "DocId"   : "256ed6c232da426681b7c45c651317895"
    }]
}

---

在序列化为JSON之前，只需使用LINQ进行简单对话：

//below should be your original list instead of this test data
var list = new List<Request>
{
    new Request {DocId = "000", DocType = "type"},
    new Request {DocId = "111", DocType = "type"},
    new Request {DocId = "222", DocType = "type"}
};

var count = 0;

var newList = list.Select(x =>
{
    x.Index = count++;
    return x;
}).ToList();

---

声明一个静态int变量来保存数字，并使用构造函数将值赋给索引

using System.Collections.Generic;
using Newtonsoft.Json;

namespace ConsoleApp2 {
  class Program {
    static void Main() {

      string json = @"[{'DocType' : 'MSWORD','DocId'   : '553ed6c232da426681b7c45c65131d33'},{'DocType' : 'MSEXCEL','DocId'   : '256ed6c232da426681b7c45c651317895'}]";
      Request.Seed = 1;
      var r = JsonConvert.DeserializeObject<List<Request>>(json);
      Request.Seed = 100000;
      r = JsonConvert.DeserializeObject<List<Request>>( json );

    }
  }
  public class Request {
    public static int Seed { get; set; }

    public Request() {
      Index = Seed++;
    }
    public int Index { get; set; }
    public string DocType { get; set; }
    public string DocId { get; set; }
  }
}

---

? newList=list。选择x，index=>x。index=index….@ErikPhilips您是100%正确的。我忘了。@PiotrStapp问题中的输入是JSON字符串？如果输入是JSON反序列化到列表，然后使用上述技巧添加索引，则应用程序在整个生命周期内只能反序列化一次？您的代码仅有效一次。在第二次调用中，索引不会从零开始，而是从最后一个值开始。@PiotrStapp我不这么认为，我们应该为您编写一个完整的解决方案。@ErikPhilips谢谢您的评论，这是有效的解决方案。我希望能回答你的问题

using System.Collections.Generic;
using Newtonsoft.Json;

namespace ConsoleApp2 {
  class Program {
    static void Main() {

      string json = @"[{'DocType' : 'MSWORD','DocId'   : '553ed6c232da426681b7c45c65131d33'},{'DocType' : 'MSEXCEL','DocId'   : '256ed6c232da426681b7c45c651317895'}]";
      Request.Seed = 1;
      var r = JsonConvert.DeserializeObject<List<Request>>(json);
      Request.Seed = 100000;
      r = JsonConvert.DeserializeObject<List<Request>>( json );

    }
  }
  public class Request {
    public static int Seed { get; set; }

    public Request() {
      Index = Seed++;
    }
    public int Index { get; set; }
    public string DocType { get; set; }
    public string DocId { get; set; }
  }
}