c# - 在 C# 中更新列表

Question

我有一个存储库类，其中包含一个列表，其中包含在我的网站上填写表格的人是否会参加我的聚会。
我使用 GetAllRespones 读取值，并使用 AddResponse 将值添加到列表中(通过接口(interface))

现在我想检查是否有人已经填写了我的表格，如果是，我想检查 WillAttend 的值是否已更改并更新它。

我可以在这里看到我在下面做了什么

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using PartyInvites.Abstract;

namespace PartyInvites.Models
{
public class GuestResponseRepository : IRepository

{
    private static List<GuestResponse> responses = new List<GuestResponse>();

    IEnumerable<GuestResponse> IRepository.GetAllResponses()
    {
        return responses;
    }

    bool IRepository.AddResponse(GuestResponse response)
    {
       bool exists = responses.Any(x => x.Email == response.Email);
        bool existsWillAttend = responses.Any(x => x.WillAttend == response.WillAttend);

        if (exists == true)
        {
            if (existsWillAttend == true)
            {
                return false;
            }

           var attend =  responses.Any(x => x.Email == response.Email && x.WillAttend == response.WillAttend);
           attend.WillAttend = response.WillAttend;
           return true;

        }

        responses.Add(response);
        return true;
    }
}
}

问题是，我在“attend.WillAttend”收到一条错误消息

the error is: bool does not contain definition for WillAttend and has no extension method 'WillAttend' accepting a first argument of type bool could be found

谁能帮我修复我的代码？ :)

Answer 1

问题在这里:

var attend = 
        responses.Any(x => x.Email == response.Email && x.WillAttend == response.WillAttend);

Any<>()返回 bool . bool没有房产WillAttend .如果您想通过 x => x.Email == response.Email && x.WillAttend == response.WillAttend 获得第一响应使用 First() (或 FirstOrDefault() 但在你的情况下，你总是至少有一个元素，所以只需使用 First() ):

var attend = responses.First(x => x.Email == response.Email && x.WillAttend != response.WillAttend);
attend.WillAttend = response.WillAttend;

如果您想要许多具有指定条件的响应，请使用 Where() :

var attend = responses.Where(x => x.Email == response.Email && x.WillAttend != response.WillAttend);

if (attend.Any())
{
    //do something
}

此外，您可以使您的方法更简单:

bool IRepository.AddResponse(GuestResponse response)
{
    if (responses.Any(x => x.Email == response.Email)) //here
    {
        if (responses.Any(x => x.WillAttend != response.WillAttend)) //here
        {
            return false;
        }

        var attend = responses.First(x => x.Email == response.Email && x.WillAttend != response.WillAttend);
        attend.WillAttend = response.WillAttend;          
        return true;
    }

    responses.Add(response);
    return true;
}