C# 元组、匿名对象、ref&out

元组

private (int number,int newNumber) CaculateByTuple(int number)
{
    return (number: number,
        newNumber: number * number);
}

private List<(int number, int newNumber)> CaculateByTuple(List<int> numbers)
{
    return numbers.AsEnumerable().Select(
        x =>
        {
            return (number: x,
            newNumber: x * x);
        })
        .ToList();
}

匿名对象

private dynamic CaculateByDynamic(int number)
{
    return new
    {
        number = number,
        newNumber = number * number
    };
}

参考资料
C# 匿名类型：https://www.w3cschool.cn/csharp/csharp-anonymous-types.html

ref&out

ref

private int CaculateByRef(ref int number)
{
    //对于ref
    //在进入方法CaculateByRef之前，number必须赋值
    //在方法CaculateByRef里面，number可以不进行修改
    number = 2;
    return number * number;
}

out

private int CaculateByOut(out int number)
{
    //对于ref
    //在进入方法CaculateByOut之前，number不必赋值
    //在方法CaculateByOut里面，number必须进行赋值
    number = 3;
    return number * number;
}

ref&out的坏处在于:
查询number值的引用时，只能查询到ref&out这个方法名上面，对于IDE来说，方法修改了一个变量值，而不是修改了number
在开发过程中的查询检索会遇到困难，如下所示：

 

 

 

 

测试方法

public void Test()
{
    //ref
    int number = 1;
    int newNumber=CaculateByRef(ref number);

    //out
    newNumber = CaculateByOut(out number);

    //元组
    var returnValues = CaculateByTuple(number);
    number = returnValues.number;
    newNumber = returnValues.newNumber;

    //匿名对象
    var returnValues2 = CaculateByDynamic(number);
    number = returnValues2.number;
    newNumber = returnValues2.newNumber;

    //元组2
    List<int> numbers = new List<int>();
    numbers.Add(1);
    numbers.Add(2);
    numbers.Add(3);
    var returnValues3 = CaculateByTuple(numbers);
}

示例

https://github.com/zLulus/NotePractice/blob/dev3/Console/ConsoleDemo/ReturnsMultipleValuesTest.cs