c#基础

属性

    public abstract class Shape
    {
        private string myId;
        public string Id 
        {
            get {return myId;}
            set { myId = value; }
        }
　　}

属性是 私有变量的 代言人，存取器. 紧挨着变量声明就好

函数重载

public abstract class Shape
{
      public abstract double Area
      { get; }
 }

 public class Squre : Shape
{
       public override double Area
       {   get{ return mySide * mySide;}}
}

索引器, 模板

class SampleCollection<T>
{
    // Declare an array to store the data elements.
    private T[] arr = new T[100];

    // Define the indexer, which will allow client code
    // to use [] notation on the class instance itself.
    // (See line 2 of code in Main below.)        
    public T this[int i]
    {
        get
        {
            // This indexer is very simple, and just returns or sets
            // the corresponding element from the internal array.
            return arr[i];
        }
        set
        {
            arr[i] = value;
        }
    }
}

// This class shows how client code uses the indexer.
class Program
{
    static void Main(string[] args)
    {
        // Declare an instance of the SampleCollection type.
        SampleCollection<string> stringCollection = new SampleCollection<string>();

        // Use [] notation on the type.
        stringCollection[0] = "Hello, World";
        System.Console.WriteLine(stringCollection[0]);
    }
}

内容都是由变量存的， 任何行为都要定义存取。

<T>模板. 

public T this[int i]:　下标　返回　string, get{}set{}