是否有一种方法可以使用Tuple类,但在其中提供项目的名称?

例如:

public Tuple<int, int, int int> GetOrderRelatedIds()

它返回OrderGroupId、OrderTypeId、OrderSubTypeId和OrderRequirementId的id。

让我的方法的用户知道哪个是哪个就好了。(当您调用该方法时,结果为result。Item1,结果。第二条,结果。Item3 result.Item4。不清楚哪个是哪个。)

(我知道我可以创建一个类来保存所有这些id,但这些id已经有自己的类,它们生活在其中,为这个方法的返回值创建一个类似乎很愚蠢。)


当前回答

如果你的项目类型都不同,这里是一个类,我做了更直观地获得他们。

这个类的用法:

var t = TypedTuple.Create("hello", 1, new MyClass());
var s = t.Get<string>();
var i = t.Get<int>();
var c = t.Get<MyClass>();

源代码:

public static class TypedTuple
{
    public static TypedTuple<T1> Create<T1>(T1 t1)
    {
        return new TypedTuple<T1>(t1);
    }

    public static TypedTuple<T1, T2> Create<T1, T2>(T1 t1, T2 t2)
    {
        return new TypedTuple<T1, T2>(t1, t2);
    }

    public static TypedTuple<T1, T2, T3> Create<T1, T2, T3>(T1 t1, T2 t2, T3 t3)
    {
        return new TypedTuple<T1, T2, T3>(t1, t2, t3);
    }

    public static TypedTuple<T1, T2, T3, T4> Create<T1, T2, T3, T4>(T1 t1, T2 t2, T3 t3, T4 t4)
    {
        return new TypedTuple<T1, T2, T3, T4>(t1, t2, t3, t4);
    }

    public static TypedTuple<T1, T2, T3, T4, T5> Create<T1, T2, T3, T4, T5>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5)
    {
        return new TypedTuple<T1, T2, T3, T4, T5>(t1, t2, t3, t4, t5);
    }

    public static TypedTuple<T1, T2, T3, T4, T5, T6> Create<T1, T2, T3, T4, T5, T6>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6)
    {
        return new TypedTuple<T1, T2, T3, T4, T5, T6>(t1, t2, t3, t4, t5, t6);
    }

    public static TypedTuple<T1, T2, T3, T4, T5, T6, T7> Create<T1, T2, T3, T4, T5, T6, T7>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7)
    {
        return new TypedTuple<T1, T2, T3, T4, T5, T6, T7>(t1, t2, t3, t4, t5, t6, t7);
    }

    public static TypedTuple<T1, T2, T3, T4, T5, T6, T7, T8> Create<T1, T2, T3, T4, T5, T6, T7, T8>(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7, T8 t8)
    {
        return new TypedTuple<T1, T2, T3, T4, T5, T6, T7, T8>(t1, t2, t3, t4, t5, t6, t7, t8);
    }

}

public class TypedTuple<T>
{
    protected Dictionary<Type, object> items = new Dictionary<Type, object>();

    public TypedTuple(T item1)
    {
        Item1 = item1;
    }

    public TSource Get<TSource>()
    {
        object value;
        if (this.items.TryGetValue(typeof(TSource), out value))
        {
            return (TSource)value;
        }
        else
            return default(TSource);
    }

    private T item1;
    public T Item1 { get { return this.item1; } set { this.item1 = value; this.items[typeof(T)] = value; } }
}

public class TypedTuple<T1, T2> : TypedTuple<T1>
{
    public TypedTuple(T1 item1, T2 item2)
        : base(item1)
    {
        Item2 = item2;
    }

    private T2 item2;
    public T2 Item2 { get { return this.item2; } set { this.item2 = value; this.items[typeof(T2)] = value; } }
}

public class TypedTuple<T1, T2, T3> : TypedTuple<T1, T2>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3)
        : base(item1, item2)
    {
        Item3 = item3;
    }

    private T3 item3;
    public T3 Item3 { get { return this.item3; } set { this.item3 = value; this.items[typeof(T3)] = value; } }
}

public class TypedTuple<T1, T2, T3, T4> : TypedTuple<T1, T2, T3>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3, T4 item4)
        : base(item1, item2, item3)
    {
        Item4 = item4;
    }

    private T4 item4;
    public T4 Item4 { get { return this.item4; } set { this.item4 = value; this.items[typeof(T4)] = value; } }
}

public class TypedTuple<T1, T2, T3, T4, T5> : TypedTuple<T1, T2, T3, T4>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3, T4 item4, T5 item5)
        : base(item1, item2, item3, item4)
    {
        Item5 = item5;
    }

    private T5 item5;
    public T5 Item5 { get { return this.item5; } set { this.item5 = value; this.items[typeof(T5)] = value; } }
}

public class TypedTuple<T1, T2, T3, T4, T5, T6> : TypedTuple<T1, T2, T3, T4, T5>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3, T4 item4, T5 item5, T6 item6)
        : base(item1, item2, item3, item4, item5)
    {
        Item6 = item6;
    }

    private T6 item6;
    public T6 Item6 { get { return this.item6; } set { this.item6 = value; this.items[typeof(T6)] = value; } }
}

public class TypedTuple<T1, T2, T3, T4, T5, T6, T7> : TypedTuple<T1, T2, T3, T4, T5, T6>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3, T4 item4, T5 item5, T6 item6, T7 item7)
        : base(item1, item2, item3, item4, item5, item6)
    {
        Item7 = item7;
    }

    private T7 item7;
    public T7 Item7 { get { return this.item7; } set { this.item7 = value; this.items[typeof(T7)] = value; } }
}

public class TypedTuple<T1, T2, T3, T4, T5, T6, T7, T8> : TypedTuple<T1, T2, T3, T4, T5, T6, T7>
{
    public TypedTuple(T1 item1, T2 item2, T3 item3, T4 item4, T5 item5, T6 item6, T7 item7, T8 item8)
        : base(item1, item2, item3, item4, item5, item6, item7)
    {
        Item8 = item8;
    }

    private T8 item8;
    public T8 Item8 { get { return this.item8; } set { this.item8 = value; this.items[typeof(T8)] = value; } }
}

其他回答

您可以编写一个包含元组的类。

您需要重写Equals和GetHashCode函数

和==和!=操作符。

class Program
{
    public class MyTuple
    {
        private Tuple<int, int> t;

        public MyTuple(int a, int b)
        {
            t = new Tuple<int, int>(a, b);
        }

        public int A
        {
            get
            {
                return t.Item1;
            }
        }

        public int B
        {
            get
            {
                return t.Item2;
            }
        }

        public override bool Equals(object obj)
        {
            return t.Equals(((MyTuple)obj).t);
        }

        public override int GetHashCode()
        {
            return t.GetHashCode();
        }

        public static bool operator ==(MyTuple m1, MyTuple m2)
        {
            return m1.Equals(m2);
        }

        public static bool operator !=(MyTuple m1, MyTuple m2)
        {
            return !m1.Equals(m2);
        }
    }

    static void Main(string[] args)
    {
        var v1 = new MyTuple(1, 2);
        var v2 = new MyTuple(1, 2);

        Console.WriteLine(v1 == v2);

        Dictionary<MyTuple, int> d = new Dictionary<MyTuple, int>();
        d.Add(v1, 1);

        Console.WriteLine(d.ContainsKey(v2));
    }
}

将返回:

True

True

下面是你所问问题的一个过于复杂的版本:

class MyTuple : Tuple<int, int>
{
    public MyTuple(int one, int two)
        :base(one, two)
    {

    }

    public int OrderGroupId { get{ return this.Item1; } }
    public int OrderTypeId { get{ return this.Item2; } }

}

为什么不直接创建一个类呢?

从这篇文章中复制我的答案,因为它更适合这里。

从c# v7.0开始,现在可以将元组属性命名为Item1、Item2等早先默认的名称。

命名元组字面量的属性:

var myDetails = (MyName: "Foo", MyAge: 22, MyFavoriteFood: "Bar");
Console.WriteLine($"Name - {myDetails.MyName}, Age - {myDetails.MyAge}, Passion - {myDetails.MyFavoriteFood}");

控制台的输出:

Name - Foo, Age - 22, Passion - Bar

从一个方法返回元组(有命名属性):

static void Main(string[] args)
{
    var empInfo = GetEmpInfo();
    Console.WriteLine($"Employee Details: {empInfo.firstName}, {empInfo.lastName}, {empInfo.computerName}, {empInfo.Salary}");
}

static (string firstName, string lastName, string computerName, int Salary) GetEmpInfo()
{
    //This is hardcoded just for the demonstration. Ideally this data might be coming from some DB or web service call
    return ("Foo", "Bar", "Foo-PC", 1000);
}

控制台的输出:

Employee Details: Foo, Bar, Foo-PC, 1000

创建具有命名属性的元组列表

var tupleList = new List<(int Index, string Name)>
{
    (1, "cow"),
    (5, "chickens"),
    (1, "airplane")
};

foreach (var tuple in tupleList)
    Console.WriteLine($"{tuple.Index} - {tuple.Name}");

控制台输出:

1 - cow  
5 - chickens  
1 - airplane

注意:本文中的代码片段使用了c# v6的字符串插值特性。

不,你不能命名元组成员。

中间的方法是使用ExpandoObject而不是Tuple。

在。net 4中,你也许可以看看ExpandoObject,但是,不要在这种简单的情况下使用它,因为编译时错误会变成运行时错误。

class Program
{
    static void Main(string[] args)
    {
        dynamic employee, manager;

        employee = new ExpandoObject();
        employee.Name = "John Smith";
        employee.Age = 33;

        manager = new ExpandoObject();
        manager.Name = "Allison Brown";
        manager.Age = 42;
        manager.TeamSize = 10;

        WritePerson(manager);
        WritePerson(employee);
    }
    private static void WritePerson(dynamic person)
    {
        Console.WriteLine("{0} is {1} years old.",
                          person.Name, person.Age);
        // The following statement causes an exception
        // if you pass the employee object.
        // Console.WriteLine("Manages {0} people", person.TeamSize);
    }
}
// This code example produces the following output:
// John Smith is 33 years old.
// Allison Brown is 42 years old.

另一个值得一提的是方法中的匿名类型,但是如果您想要返回它,则需要创建一个类。

var MyStuff = new
    {
        PropertyName1 = 10,
        PropertyName2 = "string data",
        PropertyName3 = new ComplexType()
    };