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HybridDictionary Constructor

Creates an empty case-sensitive HybridDictionary.

Namespace:  System.Collections.Specialized
Assembly:  System (in System.dll)

public:
HybridDictionary()

By default, the collection is case-sensitive and uses the key's implementation of Object::GetHashCode as the hash code provider and the key's implementation of Object::Equals as the comparer.

The comparer determines whether two keys are equal. Every key in a HybridDictionary must be unique.

This constructor is an O(1) operation.

The following code example demonstrates several of the properties and methods of HybridDictionary.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;

void PrintKeysAndValues1( IDictionary^ myCol );
void PrintKeysAndValues2( IDictionary^ myCol );
void PrintKeysAndValues3( HybridDictionary^ myCol );
int main()
{

   // Creates and initializes a new HybridDictionary.
   HybridDictionary^ myCol = gcnew HybridDictionary;
   myCol->Add( "Braeburn Apples", "1.49" );
   myCol->Add( "Fuji Apples", "1.29" );
   myCol->Add( "Gala Apples", "1.49" );
   myCol->Add( "Golden Delicious Apples", "1.29" );
   myCol->Add( "Granny Smith Apples", "0.89" );
   myCol->Add( "Red Delicious Apples", "0.99" );
   myCol->Add( "Plantain Bananas", "1.49" );
   myCol->Add( "Yellow Bananas", "0.79" );
   myCol->Add( "Strawberries", "3.33" );
   myCol->Add( "Cranberries", "5.98" );
   myCol->Add( "Navel Oranges", "1.29" );
   myCol->Add( "Grapes", "1.99" );
   myCol->Add( "Honeydew Melon", "0.59" );
   myCol->Add( "Seedless Watermelon", "0.49" );
   myCol->Add( "Pineapple", "1.49" );
   myCol->Add( "Nectarine", "1.99" );
   myCol->Add( "Plums", "1.69" );
   myCol->Add( "Peaches", "1.99" );

   // Display the contents of the collection using for each. This is the preferred method.
   Console::WriteLine( "Displays the elements using for each:" );
   PrintKeysAndValues1( myCol );

   // Display the contents of the collection using the enumerator.
   Console::WriteLine( "Displays the elements using the IDictionaryEnumerator:" );
   PrintKeysAndValues2( myCol );

   // Display the contents of the collection using the Keys, Values, Count, and Item properties.
   Console::WriteLine( "Displays the elements using the Keys, Values, Count, and Item properties:" );
   PrintKeysAndValues3( myCol );

   // Copies the HybridDictionary to an array with DictionaryEntry elements. 
   array<DictionaryEntry>^myArr = gcnew array<DictionaryEntry>(myCol->Count);
   myCol->CopyTo( myArr, 0 );

   // Displays the values in the array.
   Console::WriteLine( "Displays the elements in the array:" );
   Console::WriteLine( "   KEY                       VALUE" );
   for ( int i = 0; i < myArr->Length; i++ )
      Console::WriteLine( "   {0,-25} {1}", myArr[ i ].Key, myArr[ i ].Value );
   Console::WriteLine();

   // Searches for a key. 
   if ( myCol->Contains( "Kiwis" ) )
      Console::WriteLine( "The collection contains the key \"Kiwis\"." );
   else
      Console::WriteLine( "The collection does not contain the key \"Kiwis\"." );

   Console::WriteLine();

   // Deletes a key.
   myCol->Remove( "Plums" );
   Console::WriteLine( "The collection contains the following elements after removing \"Plums\":" );
   PrintKeysAndValues1( myCol );

   // Clears the entire collection.
   myCol->Clear();
   Console::WriteLine( "The collection contains the following elements after it is cleared:" );
   PrintKeysAndValues1( myCol );
}

// Uses the for each statement which hides the complexity of the enumerator. 
// NOTE: The for each statement is the preferred way of enumerating the contents of a collection. 
void PrintKeysAndValues1( IDictionary^ myCol )  {
   Console::WriteLine( "   KEY                       VALUE" );
   for each ( DictionaryEntry^ de in myCol )
      Console::WriteLine( "   {0,-25} {1}", de->Key, de->Value );
   Console::WriteLine();
}

// Uses the enumerator.  
void PrintKeysAndValues2( IDictionary^ myCol )
{
   IDictionaryEnumerator^ myEnumerator = myCol->GetEnumerator();
   Console::WriteLine( "   KEY                       VALUE" );
   while ( myEnumerator->MoveNext() )
      Console::WriteLine( "   {0,-25} {1}", myEnumerator->Key, myEnumerator->Value );

   Console::WriteLine();
}

// Uses the Keys, Values, Count, and Item properties. 
void PrintKeysAndValues3( HybridDictionary^ myCol )
{
   array<String^>^myKeys = gcnew array<String^>(myCol->Count);
   myCol->Keys->CopyTo( myKeys, 0 );
   Console::WriteLine( "   INDEX KEY                       VALUE" );
   for ( int i = 0; i < myCol->Count; i++ )
      Console::WriteLine( "   {0,-5} {1,-25} {2}", i, myKeys[ i ], myCol[ myKeys[ i ] ] );
   Console::WriteLine();
}

/*
This code produces the following output.

Displays the elements using for each:
   KEY                       VALUE
   Strawberries              3.33
   Yellow Bananas            0.79
   Cranberries               5.98
   Grapes                    1.99
   Granny Smith Apples       0.89
   Seedless Watermelon       0.49
   Honeydew Melon            0.59
   Red Delicious Apples      0.99
   Navel Oranges             1.29
   Fuji Apples               1.29
   Plantain Bananas          1.49
   Gala Apples               1.49
   Pineapple                 1.49
   Plums                     1.69
   Braeburn Apples           1.49
   Peaches                   1.99
   Golden Delicious Apples   1.29
   Nectarine                 1.99

Displays the elements using the IDictionaryEnumerator:
   KEY                       VALUE
   Strawberries              3.33
   Yellow Bananas            0.79
   Cranberries               5.98
   Grapes                    1.99
   Granny Smith Apples       0.89
   Seedless Watermelon       0.49
   Honeydew Melon            0.59
   Red Delicious Apples      0.99
   Navel Oranges             1.29
   Fuji Apples               1.29
   Plantain Bananas          1.49
   Gala Apples               1.49
   Pineapple                 1.49
   Plums                     1.69
   Braeburn Apples           1.49
   Peaches                   1.99
   Golden Delicious Apples   1.29
   Nectarine                 1.99

Displays the elements using the Keys, Values, Count, and Item properties:
   INDEX KEY                       VALUE
   0     Strawberries              3.33
   1     Yellow Bananas            0.79
   2     Cranberries               5.98
   3     Grapes                    1.99
   4     Granny Smith Apples       0.89
   5     Seedless Watermelon       0.49
   6     Honeydew Melon            0.59
   7     Red Delicious Apples      0.99
   8     Navel Oranges             1.29
   9     Fuji Apples               1.29
   10    Plantain Bananas          1.49
   11    Gala Apples               1.49
   12    Pineapple                 1.49
   13    Plums                     1.69
   14    Braeburn Apples           1.49
   15    Peaches                   1.99
   16    Golden Delicious Apples   1.29
   17    Nectarine                 1.99

Displays the elements in the array:
   KEY                       VALUE
   Strawberries              3.33
   Yellow Bananas            0.79
   Cranberries               5.98
   Grapes                    1.99
   Granny Smith Apples       0.89
   Seedless Watermelon       0.49
   Honeydew Melon            0.59
   Red Delicious Apples      0.99
   Navel Oranges             1.29
   Fuji Apples               1.29
   Plantain Bananas          1.49
   Gala Apples               1.49
   Pineapple                 1.49
   Plums                     1.69
   Braeburn Apples           1.49
   Peaches                   1.99
   Golden Delicious Apples   1.29
   Nectarine                 1.99

The collection does not contain the key "Kiwis".

The collection contains the following elements after removing "Plums":
   KEY                       VALUE
   Strawberries              3.33
   Yellow Bananas            0.79
   Cranberries               5.98
   Grapes                    1.99
   Granny Smith Apples       0.89
   Seedless Watermelon       0.49
   Honeydew Melon            0.59
   Red Delicious Apples      0.99
   Navel Oranges             1.29
   Fuji Apples               1.29
   Plantain Bananas          1.49
   Gala Apples               1.49
   Pineapple                 1.49
   Braeburn Apples           1.49
   Peaches                   1.99
   Golden Delicious Apples   1.29
   Nectarine                 1.99

The collection contains the following elements after it is cleared:
   KEY                       VALUE

*/

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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