c# – linq函数OrderByDescending和OrderBy如何在字符串长度内部

这是代码.

var lines = System.IO.File.ReadLines(@"C:test.txt");
var Minimum = lines[0];//Default length set
var Maximum = "";

foreach (string line in lines)
{    
    if (Maximum.Length < line.Length)
    {
        Maximum = line;
    }

    if (Minimum.Length > line.Length)
    {
        Minimum = line;
    }
}

使用LINQ(我的方法)替代此代码

var lines = System.IO.File.ReadLines(@"C:test.txt");
var Maximum = lines.OrderByDescending(a => a.Length).First().ToString();
var Minimum = lines.OrderBy(a => a.Length).First().ToString();

LINQ易于阅读和实现..

我想知道哪一个对性能有好处.
以及Linq如何在内部为OrderByDescending和OrderBy进行长度排序？