C#入门教程笔记

Substring(),//截取字符串,接受两个参数，第一个是偏移量，第二个是截取长度

replace(),//替换字符串，接受两个参数，第一个指定被替换的字符串，第二个指定被替换的字符串

IndexOf(),//返回指定字符在字符串中的位置，从0开始

//一个重载ToString()方法案例
//Format将double转换为string
struct Location
{
    private double x;
    private double y;

    public Location(double x,double y)
    {
        this.x = x;
        this.y = y;
    }
    public override string ToString()
    {
        return System.String.Format("Location:{0}degree,latitude:{1}degree", x, y);
    }
}

//一个访问控制字符
readonly //常用在定义常量，与const 的区别在于，readonly在程序运行时被赋值，赋值之后程序运行中不能更改值

bool result = root.Equals(root2, StringComparison.Ordinal);
            System.Console.WriteLine("{0} and {1},is{2}", root, root2, result ? ",equel." : ",not equel.");
            result = root.Equals(root2, StringComparison.OrdinalIgnoreCase);//忽略大小写
            System.Console.WriteLine("{0}and{1},is{2}", root, root2, result ? ",equel." : ",not equel.");

            //静态方法也可用
            bool isEquel = String.Equals(root, root2, StringComparison.Ordinal);
            System.Console.WriteLine(isEquel.ToString());

CompareTo() //用于根据一个字符串是小于 (<) 还是大于 (>) 另一个字符串来返回一个整数值。比较字符串时使用的是 Unicode 值，并且小写的值小于大写的值。

Split(),//Split方法将字符串拆分成带分隔符的char数组

string numString = "1287543"; //"1287543.0" will return false for a long
long number1 = 0;
bool canConvert = long.TryParse(numString, out number1);
if (canConvert == true)
  Console.WriteLine("number1 now = {0}", number1);
else
  Console.WriteLine("numString is not a valid long");

byte number2 = 0;
numString = "255"; // A value of 256 will return false
canConvert = byte.TryParse(numString, out number2);
if (canConvert == true)
  Console.WriteLine("number2 now = {0}", number2);
else
  Console.WriteLine("numString is not a valid byte");

decimal number3 = 0;
numString = "27.3"; //"27" is also a valid decimal
canConvert = decimal.TryParse(numString, out number3);
if (canConvert == true)
  Console.WriteLine("number3 now = {0}", number3);
else
  Console.WriteLine("number3 is not a valid decimal");