c# 7元组的例子

var tuple = TupleExample(key, value);

     private (string key1, long value1) ValidateAPIKeyOwnerId(string key, string value)
            {
                return (key, value);
            }
      if (!string.IsNullOrEmpty(tuple.key1) && tuple.value1 > 0)
          {
                    //your code

                }     

(double, int) t1 = (4.5, 3);
Console.WriteLine($"Tuple with elements {t1.Item1} and {t1.Item2}.");
// Output:
// Tuple with elements 4.5 and 3.

(double Sum, int Count) t2 = (4.5, 3);
Console.WriteLine($"Sum of {t2.Count} elements is {t2.Sum}.");
// Output:
// Sum of 3 elements is 4.5.

来自Docs: https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/value-tuples

c# 7元组的例子

var tuple = TupleExample(key, value);

     private (string key1, long value1) ValidateAPIKeyOwnerId(string key, string value)
            {
                return (key, value);
            }
      if (!string.IsNullOrEmpty(tuple.key1) && tuple.value1 > 0)
          {
                    //your code

                }     

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?

只是补充一下@MichaelMocko的答案。元组目前有几个陷阱:

你不能在EF表达式树中使用它们

例子:

public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        // Selecting as Tuple
        .Select(person => (person.Name, person.Surname))
        .First();
}

这将导致编译失败，出现“表达式树可能不包含元组文字”错误。不幸的是，表达式树API在向语言中添加元组时并没有扩展对元组的支持。

跟踪(并投票)这个问题的更新:https://github.com/dotnet/roslyn/issues/12897

为了解决这个问题，你可以先将其转换为匿名类型，然后将值转换为元组:

// Will work
public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => new { person.Name, person.Surname })
        .ToList()
        .Select(person => (person.Name, person.Surname))
        .First();
}

另一种选择是使用ValueTuple。创建:

// Will work
public static (string name, string surname) GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => ValueTuple.Create(person.Name, person.Surname))
        .First();
}

引用:

https://www.damirscorner.com/blog/posts/20181207-NoSupportForTuplesInExpressionTrees.html 将匿名类型转换为新的c# 7元组类型

你不能用lambda解构它们

有一个增加支持的提议:https://github.com/dotnet/csharplang/issues/258

例子:

public static IQueryable<(string name, string surname)> GetPersonName(this PersonContext ctx, int id)
{
    return ctx.Persons
        .Where(person => person.Id == id)
        .Select(person => ValueTuple.Create(person.Name, person.Surname));
}

// This won't work
ctx.GetPersonName(id).Select((name, surname) => { return name + surname; })

// But this will
ctx.GetPersonName(id).Select(t => { return t.name + t.surname; })

引用:

c# 7元组和lambda

它们不会很好地连载

using System;
using Newtonsoft.Json;

public class Program
{
    public static void Main() {
        var me = (age: 21, favoriteFood: "Custard");
        string json = JsonConvert.SerializeObject(me);

        // Will output {"Item1":21,"Item2":"Custard"}
        Console.WriteLine(json); 
    }
}

元组字段名仅在编译时可用，并在运行时完全删除。

引用:

使值元组属性名在运行时可解析 c# 7元组支持(Newtonsoft.Json)

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()
    };