C#字符格式化占位符

using System;
using System.Diagnostics;
using System.Text;
using System.Collections;
using System.Collections.Generic;

class Test
{
    public delegate void deltest(string str);
    public static void Callbk(string str)
    {
        Console.WriteLine(str);
    }
    static void Main()
    {
        byte[] bs = { , , ,  };
        StringBuilder sb = new StringBuilder();
        for(int i=; i<bs.Length; ++i)
        {
            sb.Append(bs[i].ToString("x3"));//16进制，占3个字符宽度
            sb.Append(bs[i].ToString().PadLeft(, '_'));//占4字符宽度，不足用下划线填充
        }

        Console.WriteLine(sb); //
    }

}