C#学习追根溯源之集合方法集

1. System.Collections命名空间中的枚举器接口（IEnumerator）

   ***attention field :   object Current{get;}

   ***interface method: bool MoveNext()

   ***interface method: void Reset();
   

   using System;
   using System.Runtime.InteropServices;
   namespace System.Collections
   {
       // Summary:
       //     Supports a simple iteration over a nongeneric collection.
       [ComVisible(true)]
       [Guid("496B0ABF-CDEE-11d3-88E8-00902754C43A")]
       public interface IEnumerator
       {
           // Summary:
           //     Gets the current element in the collection.
           //
           // Returns:
           //     The current element in the collection.
           //
           // Exceptions:
           //   System.InvalidOperationException:
           //     The enumerator is positioned before the first element of the collection or
           //     after the last element.
           object Current { get; }
   
           // Summary:
           //     Advances the enumerator to the next element of the collection.
           //
           // Returns:
           //     true if the enumerator was successfully advanced to the next element; false
           //     if the enumerator has passed the end of the collection.
           //
           // Exceptions:
           //   System.InvalidOperationException:
           //     The collection was modified after the enumerator was created.
           bool MoveNext();
           //
           // Summary:
           //     Sets the enumerator to its initial position, which is before the first element
           //     in the collection.
           //
           // Exceptions:
           //   System.InvalidOperationException:
           //     The collection was modified after the enumerator was created.
           void Reset();
       }
   }

2.System.Collections命名空间中的可枚举类型接口（IEnumerable）

***interface method: GetEnumerator()

using System.Runtime.InteropServices;
namespace System.Collections
{
    // Summary:
    //     Exposes the enumerator, which supports a simple iteration over a non-generic
    //     collection.
    [ComVisible(true)]
    [Guid("496B0ABE-CDEE-11d3-88E8-00902754C43A")]
    public interface IEnumerable
    {
        // Summary:
        //     Returns an enumerator that iterates through a collection.
        //
        // Returns:
        //     An System.Collections.IEnumerator object that can be used to iterate through
        //     the collection.
        [DispId(-4)]
        IEnumerator GetEnumerator();
    }
}

3.System.Collections命名空间中的集合接口（ICollection）

***field: int Count{get;}

***field: bool isSynchronized{get;}

***field: object SyncRoot{get;}//同步根

***inteface method: CopyTo(Array array,int index);//attention there is a argument:Array

using System;
using System.Runtime.InteropServices;

namespace System.Collections
{
    // Summary:
    //     Defines size, enumerators, and synchronization methods for all nongeneric
    //     collections.
    [ComVisible(true)]
    public interface ICollection : IEnumerable
    {
        // Summary:
        //     Gets the number of elements contained in the System.Collections.ICollection.
        //
        // Returns:
        //     The number of elements contained in the System.Collections.ICollection.
        int Count { get; }
        //
        // Summary:
        //     Gets a value indicating whether access to the System.Collections.ICollection
        //     is synchronized (thread safe).
        //
        // Returns:
        //     true if access to the System.Collections.ICollection is synchronized (thread
        //     safe); otherwise, false.
        bool IsSynchronized { get; }
        //
        // Summary:
        //     Gets an object that can be used to synchronize access to the System.Collections.ICollection.
        //
        // Returns:
        //     An object that can be used to synchronize access to the System.Collections.ICollection.
        object SyncRoot { get; }

        // Summary:
        //     Copies the elements of the System.Collections.ICollection to an System.Array,
        //     starting at a particular System.Array index.
        //
        // Parameters:
        //   array:
        //     The one-dimensional System.Array that is the destination of the elements
        //     copied from System.Collections.ICollection. The System.Array must have zero-based
        //     indexing.
        //
        //   index:
        //     The zero-based index in array at which copying begins.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     array is null.
        //
        //   System.ArgumentOutOfRangeException:
        //     index is less than zero.
        //
        //   System.ArgumentException:
        //     array is multidimensional.-or- The number of elements in the source System.Collections.ICollection
        //     is greater than the available space from index to the end of the destination
        //     array.
        //
        //   System.ArgumentException:
        //     The type of the source System.Collections.ICollection cannot be cast automatically
        //     to the type of the destination array.
        void CopyTo(Array array, int index);
    }
}

4.System.Collections命名空间中的列表接口（IList）

***field: bool IsFixedSize{get;}

***field: bool IsReadOnly{get;}

***indexer: object this[int index]{get;set;}//索引器 (indexer)是这样一个成员：它支持按照索引数组的方法来索引对象。索引器的声明与属性类似，不同的是该成员的名称是this，后跟一个位于定界符[和]之间的参数列表。在索引器的访问器中可以使用这些参数。与属性类似，索引器可以是读写、只读和只写的，并且索引器的访问器可以是虚的。

***interface method: int Add(object value);

***interface method: void Clear();

***interface method: bool Contains(object value);

***interface method: int IndexOf(object value);

***interface method:void Insert(int index,object value);

***interface method:void Remove(object value);

***interface method: void RemoveAt(int index);

using System;
using System.Reflection;
using System.Runtime.InteropServices;

namespace System.Collections
{
    // Summary:
    //     Represents a non-generic collection of objects that can be individually accessed
    //     by index.
    [ComVisible(true)]
    public interface IList : ICollection, IEnumerable
    {
        // Summary:
        //     Gets a value indicating whether the System.Collections.IList has a fixed
        //     size.
        //
        // Returns:
        //     true if the System.Collections.IList has a fixed size; otherwise, false.
        bool IsFixedSize { get; }
        //
        // Summary:
        //     Gets a value indicating whether the System.Collections.IList is read-only.
        //
        // Returns:
        //     true if the System.Collections.IList is read-only; otherwise, false.
        bool IsReadOnly { get; }

        // Summary:
        //     Gets or sets the element at the specified index.
        //
        // Parameters:
        //   index:
        //     The zero-based index of the element to get or set.
        //
        // Returns:
        //     The element at the specified index.
        //
        // Exceptions:
        //   System.ArgumentOutOfRangeException:
        //     index is not a valid index in the System.Collections.IList.
        //
        //   System.NotSupportedException:
        //     The property is set and the System.Collections.IList is read-only.
        object this[int index] { get; set; }

        // Summary:
        //     Adds an item to the System.Collections.IList.
        //
        // Parameters:
        //   value:
        //     The object to add to the System.Collections.IList.
        //
        // Returns:
        //     The position into which the new element was inserted, or -1 to indicate that
        //     the item was not inserted into the collection,
        //
        // Exceptions:
        //   System.NotSupportedException:
        //     The System.Collections.IList is read-only.-or- The System.Collections.IList
        //     has a fixed size.
        int Add(object value);
        //
        // Summary:
        //     Removes all items from the System.Collections.IList.
        //
        // Exceptions:
        //   System.NotSupportedException:
        //     The System.Collections.IList is read-only.
        void Clear();
        //
        // Summary:
        //     Determines whether the System.Collections.IList contains a specific value.
        //
        // Parameters:
        //   value:
        //     The object to locate in the System.Collections.IList.
        //
        // Returns:
        //     true if the System.Object is found in the System.Collections.IList; otherwise,
        //     false.
        bool Contains(object value);
        //
        // Summary:
        //     Determines the index of a specific item in the System.Collections.IList.
        //
        // Parameters:
        //   value:
        //     The object to locate in the System.Collections.IList.
        //
        // Returns:
        //     The index of value if found in the list; otherwise, -1.
        int IndexOf(object value);
        //
        // Summary:
        //     Inserts an item to the System.Collections.IList at the specified index.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which value should be inserted.
        //
        //   value:
        //     The object to insert into the System.Collections.IList.
        //
        // Exceptions:
        //   System.ArgumentOutOfRangeException:
        //     index is not a valid index in the System.Collections.IList.
        //
        //   System.NotSupportedException:
        //     The System.Collections.IList is read-only.-or- The System.Collections.IList
        //     has a fixed size.
        //
        //   System.NullReferenceException:
        //     value is null reference in the System.Collections.IList.
        void Insert(int index, object value);
        //
        // Summary:
        //     Removes the first occurrence of a specific object from the System.Collections.IList.
        //
        // Parameters:
        //   value:
        //     The object to remove from the System.Collections.IList.
        //
        // Exceptions:
        //   System.NotSupportedException:
        //     The System.Collections.IList is read-only.-or- The System.Collections.IList
        //     has a fixed size.
        void Remove(object value);
        //
        // Summary:
        //     Removes the System.Collections.IList item at the specified index.
        //
        // Parameters:
        //   index:
        //     The zero-based index of the item to remove.
        //
        // Exceptions:
        //   System.ArgumentOutOfRangeException:
        //     index is not a valid index in the System.Collections.IList.
        //
        //   System.NotSupportedException:
        //     The System.Collections.IList is read-only.-or- The System.Collections.IList
        //     has a fixed size.
        void RemoveAt(int index);
    }
}

5.介绍一种实现了以上其中三个接口的抽象类（CollectionBase）

扫盲：如果一个类不与具体的事物相联系，而只是表达一种抽象的概念，仅仅是作为其派生类的一个基类，这样的类就是抽象类，在抽象类中声明方法时，如果加上abstract时就是抽象方法。

抽象类与非抽象类的主要区别：

·抽象类不能直接被实例化

·抽象类中可以包含抽象成员，但非抽象类中不可以

·抽象类不能被密封

抽象方法概述及声明

声明抽象方法时需注意：·抽象方法必须声明在抽象类中　　·声明抽象方法时，不能使用virtual、static、private修饰符。

在抽象类中抽象方法不提供实现。

抽象类和接口的区别：

·它们的派生类只能继承一个基类，即只能继承一个抽象类，但是可以继承多个接口。

·抽象类中可以定义成员的实现，但接口中不可以。

·抽象类中包含字段、构造函数、析构函数、静态成员或常量等，接口中不可以。

·抽象类中的成员可以私有的(只要不是抽象的)、受保护的、内部的或受保护的内部成员，但接口中的成员必须是公共的。

PS：抽象类和接口这两种类型用于完全不同的目的。抽象类主要用作对象系列的基类，共享某些主要特性，例如共同的目的和结构。接口则主要用于类，这些类在基础水平上有所不同，但仍然可以完成某些相同的任务。

***construction method: protected CollectionBase();

***construction method: protected CollectionBase();

***normal field:public int Capacity{get;set;}

***normal field: public int Count{get;}

***normal field: protected ArrayList InnerList{get;}//attention return value type:ArrayList

***normal field:protected IList List{get;}// attention return value type:IList

***normal method:public void Clear();

***normal method:public IEnumerator GetEnumerator();//attention return value type IEnumerator

***normal method: protected virtual void OnClear();

***normal method:protected virtual void OnClearComplete();

***normal method:protected virtual void OnInsert(int index,object value);

***normal method:protected virtual void OnInsertComplete(int index,object value);

***normal method:protected virtual void OnRemove(int index,object value);

***normal method:protected virtual void OnRemoveComplete(int index,object value);

***normal method:protected virtual void OnSet(int index,object oldValue,object newValue);

***normal method:protected virtual void OnSetComplete(int index,object oldValue,object newValue);

***normal method:protected virtual void OnValidate(object value);

***normal method:public void RemoveAt(int index);

using System;
using System.Runtime.InteropServices;

namespace System.Collections
{
    // Summary:
    //     Provides the abstract base class for a strongly typed collection.
    [Serializable]
    [ComVisible(true)]
    public abstract class CollectionBase : IList, ICollection, IEnumerable
    {
        // Summary:
        //     Initializes a new instance of the System.Collections.CollectionBase class
        //     with the default initial capacity.
        protected CollectionBase();
        //
        // Summary:
        //     Initializes a new instance of the System.Collections.CollectionBase class
        //     with the specified capacity.
        //
        // Parameters:
        //   capacity:
        //     The number of elements that the new list can initially store.
        protected CollectionBase(int capacity);

        // Summary:
        //     Gets or sets the number of elements that the System.Collections.CollectionBase
        //     can contain.
        //
        // Returns:
        //     The number of elements that the System.Collections.CollectionBase can contain.
        //
        // Exceptions:
        //   System.ArgumentOutOfRangeException:
        //     System.Collections.CollectionBase.Capacity is set to a value that is less
        //     than System.Collections.CollectionBase.Count.
        //
        //   System.OutOfMemoryException:
        //     There is not enough memory available on the system.
        [ComVisible(false)]
        public int Capacity { get; set; }
        //
        // Summary:
        //     Gets the number of elements contained in the System.Collections.CollectionBase
        //     instance. This property cannot be overridden.
        //
        // Returns:
        //     The number of elements contained in the System.Collections.CollectionBase
        //     instance.Retrieving the value of this property is an O(1) operation.
        public int Count { get; }
        //
        // Summary:
        //     Gets an System.Collections.ArrayList containing the list of elements in the
        //     System.Collections.CollectionBase instance.
        //
        // Returns:
        //     An System.Collections.ArrayList representing the System.Collections.CollectionBase
        //     instance itself.Retrieving the value of this property is an O(1) operation.
        protected ArrayList InnerList { get; }
        //
        // Summary:
        //     Gets an System.Collections.IList containing the list of elements in the System.Collections.CollectionBase
        //     instance.
        //
        // Returns:
        //     An System.Collections.IList representing the System.Collections.CollectionBase
        //     instance itself.
        protected IList List { get; }

        // Summary:
        //     Removes all objects from the System.Collections.CollectionBase instance.
        //     This method cannot be overridden.
        public void Clear();
        //
        // Summary:
        //     Returns an enumerator that iterates through the System.Collections.CollectionBase
        //     instance.
        //
        // Returns:
        //     An System.Collections.IEnumerator for the System.Collections.CollectionBase
        //     instance.
        public IEnumerator GetEnumerator();
        //
        // Summary:
        //     Performs additional custom processes when clearing the contents of the System.Collections.CollectionBase
        //     instance.
        protected virtual void OnClear();
        //
        // Summary:
        //     Performs additional custom processes after clearing the contents of the System.Collections.CollectionBase
        //     instance.
        protected virtual void OnClearComplete();
        //
        // Summary:
        //     Performs additional custom processes before inserting a new element into
        //     the System.Collections.CollectionBase instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which to insert value.
        //
        //   value:
        //     The new value of the element at index.
        protected virtual void OnInsert(int index, object value);
        //
        // Summary:
        //     Performs additional custom processes after inserting a new element into the
        //     System.Collections.CollectionBase instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which to insert value.
        //
        //   value:
        //     The new value of the element at index.
        protected virtual void OnInsertComplete(int index, object value);
        //
        // Summary:
        //     Performs additional custom processes when removing an element from the System.Collections.CollectionBase
        //     instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which value can be found.
        //
        //   value:
        //     The value of the element to remove from index.
        protected virtual void OnRemove(int index, object value);
        //
        // Summary:
        //     Performs additional custom processes after removing an element from the System.Collections.CollectionBase
        //     instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which value can be found.
        //
        //   value:
        //     The value of the element to remove from index.
        protected virtual void OnRemoveComplete(int index, object value);
        //
        // Summary:
        //     Performs additional custom processes before setting a value in the System.Collections.CollectionBase
        //     instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which oldValue can be found.
        //
        //   oldValue:
        //     The value to replace with newValue.
        //
        //   newValue:
        //     The new value of the element at index.
        protected virtual void OnSet(int index, object oldValue, object newValue);
        //
        // Summary:
        //     Performs additional custom processes after setting a value in the System.Collections.CollectionBase
        //     instance.
        //
        // Parameters:
        //   index:
        //     The zero-based index at which oldValue can be found.
        //
        //   oldValue:
        //     The value to replace with newValue.
        //
        //   newValue:
        //     The new value of the element at index.
        protected virtual void OnSetComplete(int index, object oldValue, object newValue);
        //
        // Summary:
        //     Performs additional custom processes when validating a value.
        //
        // Parameters:
        //   value:
        //     The object to validate.
        //
        // Exceptions:
        //   System.ArgumentNullException:
        //     value is null.
        protected virtual void OnValidate(object value);
        //
        // Summary:
        //     Removes the element at the specified index of the System.Collections.CollectionBase
        //     instance. This method is not overridable.
        //
        // Parameters:
        //   index:
        //     The zero-based index of the element to remove.
        //
        // Exceptions:
        //   System.ArgumentOutOfRangeException:
        //     index is less than zero.-or-index is equal to or greater than System.Collections.CollectionBase.Count.
        public void RemoveAt(int index);
    }
}