C#排序，无法将Lambda表达式转换为System.Array [英] C# Sort, cannot convert lambda expression to System.Array

问题描述

根据我在.Sort()上找到的内容，这应该可以工作

using System;
using System.Linq;

public class Test
{
    public static void Main()
    {
        int[] test = new int[] {6, 2, 1, 4, 9, 3, 7};
        test.Sort((a,b) => a<b);
    }
}

但是，我收到此错误消息:

error CS1660: Cannot convert `lambda expression' to non-delegate type `System.Array'

这是我发现该错误的最简单版本.就我而言，我正在使用一个字符串，为它提供一个复杂的排名值，然后进行比较.

我在这里想念什么?

解决方案

排序过载，您期望

另外，对于数组，Sort方法是static，因此您使用类名而不是实例来调用它:

Array.Sort(test, (left, right) => left.CompareTo(right));

CompareTo是IComparable类型(如int)的内置函数，它以上述方式返回int，因此便于进行排序. /p>

Based on what I've found on .Sort() this should work

using System;
using System.Linq;

public class Test
{
    public static void Main()
    {
        int[] test = new int[] {6, 2, 1, 4, 9, 3, 7};
        test.Sort((a,b) => a<b);
    }
}

However, I'm getting this error message:

error CS1660: Cannot convert `lambda expression' to non-delegate type `System.Array'

That's the simplest version I could find to get that error. In my case, I'm taking a string, giving it a complex ranking value, and comparing that.

What am I missing here?

解决方案

The overload of Sort that you are after expects a delegate that takes in two objects of the type contained within the array, and returns an int. You need to change your expression to return an int, where you return a negative value for items that come before the other, zero when the items are "equal", and a positive value for items that come after the other.

Also, for arrays the Sort method is static, so you call it using the class name, not as an instance:

Array.Sort(test, (left, right) => left.CompareTo(right));

CompareTo is a built-in function on types that are IComparable (like int), and it returns an int in the manner I described above, so it is convenient to use for sorting.

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