C# 将列表中的列表聚合为一个列表

我有这些定义

ClassCountryCollection

定义为：

public class ClassCountryCollection : KeyedCollection<string, ClassCountry>
    {
        protected override IEnumerable<string> GetKey(ClassCountry i)
        {
            return i.GetKey(i.Key);
        }
    }

public class ClassCityCollection : KeyedCollection<string, ClassCity>
{
    protected override string GetKeyForItem(ClassCity i)
    {
        return i.Name;
    }
}

ClassCityCollection

定义为：

public class ClassCountryCollection : KeyedCollection<string, ClassCountry>
    {
        protected override IEnumerable<string> GetKey(ClassCountry i)
        {
            return i.GetKey(i.Key);
        }
    }

public class ClassCityCollection : KeyedCollection<string, ClassCity>
{
    protected override string GetKeyForItem(ClassCity i)
    {
        return i.Name;
    }
}

我有一个类型为

ClassCountryCollection

country

1. Key=Spain, ClassCityCollection{{Population=55,Name=Barcelona},{Population=65,Name=Madrid}}
2. Key=Germany, ClassCityCollection{{Population=12,Name=Berlin},{Population=125,Name=Dresden}}

我想创建一个列表，使上面的内容

1. {"Spain|Population=55,Name=Barcelona,Population=65,Name=Madrid"}
2. {"Germany|Population=12,Name=Berlin,Population=125,Name=Dresden"}

我试过了

country.Select(x => new { x.ClassCityList.Select(w => string.Join(",",w.ToString().ToList())), x.Key }).ToList();

---

然后我陷入困境，不知道如何继续。也许我在那里的某个地方创建了

ToString（）

，使它更简单。

我假设了类结构并返回了这段代码

    namespace welcome
   {

class Program
{
    static void Main(string[] args)
    {

        ClassCountryCollection cc = new ClassCountryCollection();

        var c1 = new ClassCountry()
        {
            Key = "Spain",
            ClassCityList = new ClassCityCollection{
                new ClassCity{Name ="Barcelona", Population = 55},
                new ClassCity{Name ="Madrid", Population = 65},
            }
        };

        var c2 = new ClassCountry()
        {
            Key = "Germany",
            ClassCityList = new ClassCityCollection{
                new ClassCity{Name ="Berlin", Population = 12},
                new ClassCity{Name ="Dresden", Population = 125},
            }
        };

        cc.Add(c1);
        cc.Add(c2);

        var g = cc.Select(x => x.Key + "|" + x.ClassCityList.Select(x => nameof(x.Population) + "=" + x.Population + "," + nameof(x.Name) + "=" + x.Name).Aggregate((d, s) => d + "," + s));
        foreach (var item in g)
        {
            System.Console.WriteLine(item);
        }
        Console.ReadLine();
    }
}

public class ClassCountryCollection : KeyedCollection<string, ClassCountry>
{

    protected override string GetKeyForItem(ClassCountry item)
    {
        return item.Key;
    }

}
public class ClassCountry
{
    public string Key { get; set; }
    public ClassCityCollection ClassCityList { get; set; }
}

public class ClassCityCollection : KeyedCollection<string, ClassCity>
{
    protected override string GetKeyForItem(ClassCity i)
    {
        return i.Name;
    }
}


public class ClassCity
{
    public int Population { get; set; }
    public string Name { get; set; }

}
}

按键然后按名称排序时 输出为

  Germany|Population=12,Name=Berlin,Population=125,Name=Dresden
  Spain|Population=55,Name=Barcelona,Population=65,Name=Madrid

代码需要修改为

  var g = cc.OrderBy(x=>x.Key).Select(x=>x.Key + "|" + x.ClassCityList.OrderBy(x=>x.Name).Select(x=>nameof(x.Population) +"=" + x.Population+","+nameof(x.Name) +"="+x.Name).Aggregate((d,s)=>d+","+s)); 

---

我假设类结构并返回此代码

    namespace welcome
   {

class Program
{
    static void Main(string[] args)
    {

        ClassCountryCollection cc = new ClassCountryCollection();

        var c1 = new ClassCountry()
        {
            Key = "Spain",
            ClassCityList = new ClassCityCollection{
                new ClassCity{Name ="Barcelona", Population = 55},
                new ClassCity{Name ="Madrid", Population = 65},
            }
        };

        var c2 = new ClassCountry()
        {
            Key = "Germany",
            ClassCityList = new ClassCityCollection{
                new ClassCity{Name ="Berlin", Population = 12},
                new ClassCity{Name ="Dresden", Population = 125},
            }
        };

        cc.Add(c1);
        cc.Add(c2);

        var g = cc.Select(x => x.Key + "|" + x.ClassCityList.Select(x => nameof(x.Population) + "=" + x.Population + "," + nameof(x.Name) + "=" + x.Name).Aggregate((d, s) => d + "," + s));
        foreach (var item in g)
        {
            System.Console.WriteLine(item);
        }
        Console.ReadLine();
    }
}

public class ClassCountryCollection : KeyedCollection<string, ClassCountry>
{

    protected override string GetKeyForItem(ClassCountry item)
    {
        return item.Key;
    }

}
public class ClassCountry
{
    public string Key { get; set; }
    public ClassCityCollection ClassCityList { get; set; }
}

public class ClassCityCollection : KeyedCollection<string, ClassCity>
{
    protected override string GetKeyForItem(ClassCity i)
    {
        return i.Name;
    }
}


public class ClassCity
{
    public int Population { get; set; }
    public string Name { get; set; }

}
}

按键然后按名称排序时 输出为

  Germany|Population=12,Name=Berlin,Population=125,Name=Dresden
  Spain|Population=55,Name=Barcelona,Population=65,Name=Madrid

代码需要修改为

  var g = cc.OrderBy(x=>x.Key).Select(x=>x.Key + "|" + x.ClassCityList.OrderBy(x=>x.Name).Select(x=>nameof(x.Population) +"=" + x.Population+","+nameof(x.Name) +"="+x.Name).Aggregate((d,s)=>d+","+s)); 

---

您的示例无法编译。class

KeyCollection

是否来自standart图书馆？我猜你的意思是

KeyedCollection

。您是否希望生成的集合的类型为

IEnumerable

？请提供最小的可复制示例。是的，这就是

KeyedCollection

。不需要数不清。我不能复制这个，因为我是从一个大项目里拿的。定义所有可复制的内容需要十几个页面，您是否希望结果是元素的集合，其中每个元素都有两个字段：第一个字段-

字符串CountryName

，第二个字段-

字符串Cities

，用逗号分隔？您的示例无法编译。class

KeyCollection

是否来自standart图书馆？我猜你的意思是

KeyedCollection

。您是否希望生成的集合的类型为

IEnumerable

？请提供最小的可复制示例。是的，这就是

KeyedCollection

。不需要数不清。我不能复制这个，因为我是从一个大项目里拿的。定义所有可复制的内容需要十几页，您是否希望结果是元素的集合，其中每个元素有两个字段：第一个字段-

字符串CountryName

，第二个字段-

字符串Cities

，用逗号分隔？谢谢。我做了一些小改动，它完全符合我的需要。这个问题有点离题，所以这对我来说太完美了<代码>抄送选择（x=>x.Key+“|”+x.ClassCityList.Select（k=>k.Name+“=”+k.Population）。聚合（（d，s）=>d+，“+s））.ToList（）。若你们不介意的话，有一件事，我怎样才能确保上面的列表是按x键排序的，然后是按k名排序的？谢谢。我做了一些小改动，它完全符合我的需要。这个问题有点离题，所以这对我来说太完美了<代码>抄送选择（x=>x.Key+“|”+x.ClassCityList.Select（k=>k.Name+“=”+k.Population）。聚合（（d，s）=>d+，“+s））.ToList（）。若你们不介意的话，有一件事，我怎样才能确保上面的列表是按x.Key排序的，然后是按k.Name排序的？