Multiparameter Indexer in C#

最新推荐文章于 2025-02-06 20:21:43 发布

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最新推荐文章于 2025-02-06 20:21:43 发布

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分类专栏： WINFORM 文章标签： c# output string constructor integer class

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该博客展示了用C#实现电话目录多参数索引器的代码。定义了PhoneDir类，包含不同类型的索引器，可根据位置、姓名、电话号码等进行读写操作。还给出了使用示例及输出结果，展示了索引器在不同场景下的调用情况。

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By Ramkumar Durgam

// ' PhoneDirIndex.cs - PhoneDirectory to simulate the use of an Multiparameter Indexer using C#
// -----------------------------------------------------------------------------------------------------
//
using System;

namespace PhoneDirIndexer
{
 class PhoneDir
 {
  private string[] _name;
  private uint[] _phoneNumber;
  private ushort _size;

  public PhoneDir(ushort size)    // Default Constructor
  {
   _size = size;
   _name = new string[size];
   _phoneNumber = new uint[size];

   for (int i=0; i < size; i++)
   {
    _name[i] ="No Name";
    _phoneNumber[i] = 0;
   }
  }


  // Indexer 1.0 - Read/Write Indexer (returns the Name and Phonenumber based on the Position and sets the Name)
  public string this[int pos]
  {
   get 
   { 
    Console.Write("Calling Get on Indexer 1.0...");
    return (_name[pos] + "(" + _phoneNumber[pos] +")") ; 
   }

   set 
   { 
    Console.WriteLine("Calling Set on Indexer 1.0...");
    _name[pos] = value; 
   }
  }


  // Indexer 2.0 - Read/Write Indexer (returns the Name and Phonenumber based on the Position and sets the Name)
  public string this[string name]
  {
   get 
   { 
    Console.Write("Calling Get on Indexer 2.0...");
    int pos;
    pos = -1;
    for (int i=0;i < _size;i++)
    {
     if(_name[i] == name)
     {
      pos = i;
      break;
     }
    }
    if (pos >=0)
     return (_name[pos] + "(" + _phoneNumber[pos] +")") ; 
    else
     return "";
   }
   set 
   { 
    Console.WriteLine("Calling Set on Indexer 2.0...");
    int pos;
    pos = -1;
    for (int i=0;i < _size;i++)
    {
     if(_name[i] == name)
     {
      pos = i;
      break;
     }
    }
    if (pos >=0) 
     _phoneNumber[pos] = Convert.ToUInt16(value); 
   }
  }


  // Indexer 3.0 - Read/Write Indexer to return the name for a given phone number and updates a phonenumber for a given phone number
  public string this[uint phone]
  {
   get    // Returns the name for a given phone number
   {
    Console.Write("Calling Get on Indexer 3.0...");
    int pos = -1;
    for (int i =0; i <  _size; i++)
    {
     if (_phoneNumber[i] == phone)
     {
      pos = i;
      break;
     }
    }
    if (pos >=0 )
     return ( _name[pos] );
    else
     return "";
   }
   set   // Set (updates) the phone number(s) for a given Phone number
   {
    Console.WriteLine("Calling Set on Indexer 3.0...");
    for (int i =0;i < _size; i++)
    {
     if (_phoneNumber[i] == phone)
      _phoneNumber[i] = Convert.ToUInt16(value);
    }
   }
  }


  // Indexer 4.0 - Readonly Indexer (returns the Position for a given Name and Phonenumber combination)
  public int this[string name,uint phone]
  {
   get 
   {
    Console.Write("Calling ReadOnly Indexer 4.0...");
    int pos = -1;

    for (int i=0; i < _size; i++)
    {
     if (_name[i] == name && _phoneNumber[i] == phone)
     {
      pos = i;
      break;
     }
    }
    return pos;
   }
  }

  
 }
 
 class PhoneDirUI
 {
  static void Main(string[] args)
  {
   int noOfListings = 5;
   PhoneDir listing = new PhoneDir(5)  ;

   listing[1] = "John.A";      // OUTPUT: "Calling Set on Indexer 1.0..."
   listing[3] = "John.B";      // OUTPUT: "Calling Set on Indexer 1.0..."

   listing["John.A"] = "1111";    // OUTPUT: "Calling Set on Indexer 2.0..."
   
   listing[1111u] = "1234";     // OUTPUT: "Calling Set on Indexer 3.0..." 
                // Note: 'u' (next to the number) is the only one that causes Indexer3.0 to be called
                //         Without that Indexer 1.0 would have been called becuase it thinks its an integer and not a uint
   
   listing["John.B"] = "2222";    // OUTPUT: "Calling Set on Indexer 2.0..."


   for (int i=0;i < noOfListings; i++)
   {
    Console.WriteLine("listing[{0}] : {1}",i,listing[i]);  //  OUTPUT: "Calling Get on Indexer 1.0... listing[i] : _name(_phone)
   }

   Console.WriteLine("Person Located in Phone number 1111..." + listing[1111u]);  
       //OUTPUT: Calling Get on Indexer 3.0 ... Person Located in Phone Number 1111... 

   Console.WriteLine("Person Located in Phone number 1234..." + listing[1234u]);  
      //OUTPUT: Calling Get on Indexer 3.0 ... Person Located in Phone Number 1234....John.A  (because we updated the phone number above)

   Console.WriteLine("John.B,2222 is located in..." + listing["John.B",2222]);      
     //OUTPUT: Calling ReadOnly Indexer 4.0 ... John.B,2222 is located in...3

   Console.ReadLine();
  }
 }
}

---------------------
Output
--------------------

Calling Set on Indexer 1.0...
Calling Set on Indexer 1.0...
Calling Set on Indexer 2.0...
Calling Set on Indexer 3.0...
Calling Set on Indexer 2.0...
Calling Get on Indexer 1.0...listing[0] : No Name(0)
Calling Get on Indexer 1.0...listing[1] : John.A(1234)
Calling Get on Indexer 1.0...listing[2] : No Name(0)
Calling Get on Indexer 1.0...listing[3] : John.B(2222)
Calling Get on Indexer 1.0...listing[4] : No Name(0)
Calling Get on Indexer 3.0...Person Located in Phone number 1111...
Calling Get on Indexer 3.0...Person Located in Phone number 1234...John.A
Calling ReadOnly Indexer 4.0...John.B,2222 is located in...3