C#:随记

1.实现vbs里面的DateDiff方法：（计算毫秒，s/m/d/mon/y依此类推）

DateTime startTime = DateTime.Now;
DateTime endTime = DateTime.Now;
int dateDiff = (int) new System.TimeSpan(endTime.Ticks - startTime.Ticks).TotalMilliseconds;

2.使用File类写/读log：

File.AppendAllText("1.log", "xx" + "
", Encoding.UTF8);

 string[] readAll = File.ReadAllLines("1.log");
 string str = null;
 for (int m = 0; m < readAll.Length; m++)
 {
       str += readAll[m] + "
";
  }

换行：

用stream实现：

写：
            FileStream fs = new FileStream("1.log", FileMode.Append);
            StreamWriter sw = new StreamWriter(fs);
            sw.WriteLine("contents" + "
");

读：
            FileStream fs = new FileStream("1.log", FileMode.Open);
            StreamReader sr = new StreamReader(fs);
            string strAll = sr.ReadToEnd();

对字符串排序："1.txt, 10.txt, 3.txt, 2.txt"    

期待结果 "1.txt ,2.txt,10.txt, 3.txt

 class Program
    {
        string[] arr = { "1.txt", "10.txt", "3.txt", "2.txt" };
        
        static void Main(string[] args)
        {
            Program p = new Program();
            Dictionary<int, string> dic = new Dictionary<int, string>();
          for(int i = 0 ;i< p.arr.Length;i++)
          {
            int arrInt =Convert.ToInt32(p.arr[i].Split('.')[0]);
            string arrString = p.arr[i].Split('.')[1];
           
            dic.Add(arrInt, arrString);
          }

          var query = dic.OrderBy(d => d.Key);
          foreach (var q in query)
          {
              Console.WriteLine(q.Key.ToString() +"."+  q.Value);
          }
             
            Console.ReadKey();
        }
    }

 找出字符串里所有的字母，并排序：

string str = "aiA[]@#.<>?BjckdlemCfDngpho";
            char[] tmpStr = str.ToCharArray();
            
            List<char> myList = new List<char>(); 
            for (int i = 0; i < tmpStr.Length; i++)//找字符
            {
                if ((tmpStr[i] >= 'A' && tmpStr[i] <= 'Z') || (tmpStr[i] >= 'a' && tmpStr[i] <= 'z'))
                {
                    myList.Add(tmpStr[i]);
                }
            }
            myList.Sort(); //排序
          
            for (var j = 0; j < myList.Count;j++ )
            {
                 Console.Write( myList[j].ToString()) ;
            }

            Console.ReadKey();