Markdown 功能测试

Code Block Test

四个空格

hello?
    help？

代码段直接粘贴

public static partial class ArrayExtension
{
    public static TItem[] SortBy(this TItem[] array, Func sortKeySelector)
    {
        if (array == null) {
            throw new ArgumentNullException(nameof(array));
        }
        if (sortKeySelector == null) {
            throw new ArgumentNullException(nameof(sortKeySelector));
        }

        return SortBy(array, sortKeySelector, Comparer.Default);
    }

    public static TItem[] SortBy(this TItem[] array, Func sortKeySelector, IComparer comparer)
    {
        if (array == null) {
            throw new ArgumentNullException(nameof(array));
        }
        if (sortKeySelector == null) {
            throw new ArgumentNullException(nameof(sortKeySelector));
        }
        if (comparer == null) {
            throw new ArgumentNullException(nameof(comparer));
        }
        if (array.Length == 0) {
            return array;
        }

        TKey[] keys = new TKey[array.Length];

        for (int i = 0; i < array.Length; i++) {
            keys[i] = sortKeySelector(array[i]);
        }

        Array.Sort(keys, array, comparer);

        return array;
    }
}

看起来还可以。虽然在这里讨论代码有些浮云。