using System;

using System.Collections;

​

public class ShortStringDictionary : DictionaryBase  {

​

   public String this[ String key ]  {

      get  {

         return( (String) Dictionary[key] );

      }

      set  {

         Dictionary[key] = value;

      }

   }

​

   public ICollection Keys  {

      get  {

         return( Dictionary.Keys );

      }

   }

​

   public ICollection Values  {

      get  {

         return( Dictionary.Values );

      }

   }

​

   public void Add( String key, String value )  {

      Dictionary.Add( key, value );

   }

​

   public bool Contains( String key )  {

      return( Dictionary.Contains( key ) );

   }

​

   public void Remove( String key )  {

      Dictionary.Remove( key );

   }

​

   protected override void OnInsert( Object key, Object value )  {

      if ( key.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "key must be of type String.", "key" );

        }

        else  {

         String strKey = (String) key;

         if ( strKey.Length > 5 )

            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );

      }

​

      if ( value.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "value must be of type String.", "value" );

        }

        else  {

         String strValue = (String) value;

         if ( strValue.Length > 5 )

            throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );

      }

   }

​

   protected override void OnRemove( Object key, Object value )  {

      if ( key.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "key must be of type String.", "key" );

        }

        else  {

         String strKey = (String) key;

         if ( strKey.Length > 5 )

            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );

      }

   }

​

   protected override void OnSet( Object key, Object oldValue, Object newValue )  {

      if ( key.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "key must be of type String.", "key" );

        }

        else  {

         String strKey = (String) key;

         if ( strKey.Length > 5 )

            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );

      }

​

      if ( newValue.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "newValue must be of type String.", "newValue" );

        }

        else  {

         String strValue = (String) newValue;

         if ( strValue.Length > 5 )

            throw new ArgumentException( "newValue must be no more than 5 characters in length.", "newValue" );

      }

   }

​

   protected override void OnValidate( Object key, Object value )  {

      if ( key.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "key must be of type String.", "key" );

        }

        else  {

         String strKey = (String) key;

         if ( strKey.Length > 5 )

            throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );

      }

​

      if ( value.GetType() != typeof(System.String) )

        {

            throw new ArgumentException( "value must be of type String.", "value" );

        }

        else  {

         String strValue = (String) value;

         if ( strValue.Length > 5 )

            throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );

      }

   }

}

​

public class SamplesDictionaryBase  {

​

   public static void Main()  {

​

      // Creates and initializes a new DictionaryBase.

      ShortStringDictionary mySSC = new ShortStringDictionary();

​

      // Adds elements to the collection.

      mySSC.Add( "One", "a" );

      mySSC.Add( "Two", "ab" );

      mySSC.Add( "Three", "abc" );

      mySSC.Add( "Four", "abcd" );

      mySSC.Add( "Five", "abcde" );

​

      // Display the contents of the collection using foreach. This is the preferred method.

      Console.WriteLine( "Contents of the collection (using foreach):" );

      PrintKeysAndValues1( mySSC );

​

      // Display the contents of the collection using the enumerator.

      Console.WriteLine( "Contents of the collection (using enumerator):" );

      PrintKeysAndValues2( mySSC );

​

      // Display the contents of the collection using the Keys property and the Item property.

      Console.WriteLine( "Initial contents of the collection (using Keys and Item):" );

      PrintKeysAndValues3( mySSC );

​

      // Tries to add a value that is too long.

      try  {

         mySSC.Add( "Ten", "abcdefghij" );

      }

      catch ( ArgumentException e )  {

         Console.WriteLine( e.ToString() );

      }

​

      // Tries to add a key that is too long.

      try  {

         mySSC.Add( "Eleven", "ijk" );

      }

      catch ( ArgumentException e )  {

         Console.WriteLine( e.ToString() );

      }

​

      Console.WriteLine();

​

      // Searches the collection with Contains.

      Console.WriteLine( "Contains \"Three\": {0}", mySSC.Contains( "Three" ) );

      Console.WriteLine( "Contains \"Twelve\": {0}", mySSC.Contains( "Twelve" ) );

      Console.WriteLine();

​

      // Removes an element from the collection.

      mySSC.Remove( "Two" );

​

      // Displays the contents of the collection.

      Console.WriteLine( "After removing \"Two\":" );

      PrintKeysAndValues1( mySSC );

   }

​

   // Uses the foreach statement which hides the complexity of the enumerator.

   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.

   public static void PrintKeysAndValues1( ShortStringDictionary myCol )  {

      foreach ( DictionaryEntry myDE in myCol )

         Console.WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );

      Console.WriteLine();

   }

​

   // Uses the enumerator.

   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.

   public static void PrintKeysAndValues2( ShortStringDictionary myCol )  {

      DictionaryEntry myDE;

      System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();

      while ( myEnumerator.MoveNext() )

         if ( myEnumerator.Current != null )  {

            myDE = (DictionaryEntry) myEnumerator.Current;

            Console.WriteLine( "   {0,-5} : {1}", myDE.Key, myDE.Value );

         }

      Console.WriteLine();

   }

​

   // Uses the Keys property and the Item property.

   public static void PrintKeysAndValues3( ShortStringDictionary myCol )  {

      ICollection myKeys = myCol.Keys;

      foreach ( String k in myKeys )

         Console.WriteLine( "   {0,-5} : {1}", k, myCol[k] );

      Console.WriteLine();

   }

}

​

​

/*

This code produces the following output.

​

Contents of the collection (using foreach):

   Three : abc

   Five  : abcde

   Two   : ab

   One   : a

   Four  : abcd

​

Contents of the collection (using enumerator):

   Three : abc

   Five  : abcde

   Two   : ab

   One   : a

   Four  : abcd

​

Initial contents of the collection (using Keys and Item):

   Three : abc

   Five  : abcde

   Two   : ab

   One   : a

   Four  : abcd

​

System.ArgumentException: value must be no more than 5 characters in length.

Parameter name: value

   at ShortStringDictionary.OnValidate(Object key, Object value)

   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)

   at SamplesDictionaryBase.Main()

System.ArgumentException: key must be no more than 5 characters in length.

Parameter name: key

   at ShortStringDictionary.OnValidate(Object key, Object value)

   at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)

   at SamplesDictionaryBase.Main()

​

Contains "Three": True

Contains "Twelve": False

​

After removing "Two":

   Three : abc

   Five  : abcde

   One   : a

   Four  : abcd

​

*/