C#字符串

str1 = str1.ToLower();

 str1 = str1.ToUpper();

bool result=str1.Equals(str2,StringComparison.OrdinalIgnoreCase);
if(result)
{}
else
{}

bool result=str1.Equals(str2,StringComparison.OrdinalIgnoreCase);
if(result)
{}
else
{}

char[]chs=new char[]{' ','-'};
string[]resykt=str.Split(chs);

for(int i=0;i<result.Length;i++)
{
  Console.Write(result[i]);

 string name = "小杨很邪恶";
            name=name.Replace("小杨","老苏");
            Console.WriteLine(name);
            Console.ReadKey();

 string str = "哈哈，小杨又变帅了";
            str = str.Substring(3,6);//截取字符串,从3开始截6个
            Console.WriteLine(str);
            Console.ReadKey();

string str = path.Substring(path.Length-6);
            Console.WriteLine(path);
            Console.ReadKey();

 string str = "小杨很纯洁";
            bool result = str.StartsWith("小");
            if (result)
            {
                Console.WriteLine("有这个字符串");
            }
            else
            {
                Console.WriteLine("没有这个字符串");
            }             
            Console.ReadKey();