OrderedDictionary Class

Definition

public ref class OrderedDictionary : System::Collections::IDictionary, System::Collections::Specialized::IOrderedDictionary

public ref class OrderedDictionary : System::Collections::IDictionary, System::Collections::Specialized::IOrderedDictionary, System::Runtime::Serialization::IDeserializationCallback, System::Runtime::Serialization::ISerializable

public ref class OrderedDictionary : System::Collections::Specialized::IOrderedDictionary, System::Runtime::Serialization::IDeserializationCallback, System::Runtime::Serialization::ISerializable

public class OrderedDictionary : System.Collections.IDictionary, System.Collections.Specialized.IOrderedDictionary

public class OrderedDictionary : System.Collections.IDictionary, System.Collections.Specialized.IOrderedDictionary, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

[System.Serializable]
public class OrderedDictionary : System.Collections.IDictionary, System.Collections.Specialized.IOrderedDictionary, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

public class OrderedDictionary : System.Collections.Specialized.IOrderedDictionary, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

type OrderedDictionary = class
 interface ICollection
 interface IEnumerable
 interface IDictionary
 interface IOrderedDictionary

type OrderedDictionary = class
 interface ICollection
 interface IEnumerable
 interface IDictionary
 interface IOrderedDictionary
 interface IDeserializationCallback
 interface ISerializable

type OrderedDictionary = class
 interface ICollection
 interface IEnumerable
 interface IDictionary
 interface IOrderedDictionary
 interface ISerializable
 interface IDeserializationCallback

[<System.Serializable>]
type OrderedDictionary = class
 interface IOrderedDictionary
 interface IDictionary
 interface ICollection
 interface IEnumerable
 interface ISerializable
 interface IDeserializationCallback

Public Class OrderedDictionary
Implements IDictionary, IOrderedDictionary

Public Class OrderedDictionary
Implements IDeserializationCallback, IDictionary, IOrderedDictionary, ISerializable

Public Class OrderedDictionary
Implements IDeserializationCallback, IOrderedDictionary, ISerializable

Inheritance

Object

OrderedDictionary

Derived

System.Web.Configuration.AdapterDictionary

Attributes

SerializableAttribute

Implements

ICollection IDictionary IEnumerable IOrderedDictionary IDeserializationCallback ISerializable

Examples

The following code example demonstrates the creation, population and modification of an OrderedDictionary collection, as well as two techniques to display the contents of the OrderedDictionary: one using the Keys and Values properties and the other creating an enumerator through the GetEnumerator method.

// The following code example enumerates the elements of a OrderedDictionary.
using System;
using System.Collections;
using System.Collections.Specialized;

public class OrderedDictionarySample
{
 public static void Main()
 {

 // Creates and initializes a OrderedDictionary.
 OrderedDictionary myOrderedDictionary = new OrderedDictionary();
 myOrderedDictionary.Add("testKey1", "testValue1");
 myOrderedDictionary.Add("testKey2", "testValue2");
 myOrderedDictionary.Add("keyToDelete", "valueToDelete");
 myOrderedDictionary.Add("testKey3", "testValue3");

 ICollection keyCollection = myOrderedDictionary.Keys;
 ICollection valueCollection = myOrderedDictionary.Values;

 // Display the contents using the key and value collections
 DisplayContents(keyCollection, valueCollection, myOrderedDictionary.Count);

 // Modifying the OrderedDictionary
 if (!myOrderedDictionary.IsReadOnly)
 {
 // Insert a new key to the beginning of the OrderedDictionary
 myOrderedDictionary.Insert(0, "insertedKey1", "insertedValue1");

 // Modify the value of the entry with the key "testKey2"
 myOrderedDictionary["testKey2"] = "modifiedValue";

 // Remove the last entry from the OrderedDictionary: "testKey3"
 myOrderedDictionary.RemoveAt(myOrderedDictionary.Count - 1);

 // Remove the "keyToDelete" entry, if it exists
 if (myOrderedDictionary.Contains("keyToDelete"))
 {
 myOrderedDictionary.Remove("keyToDelete");
 }
 }

 Console.WriteLine(
 "{0}Displaying the entries of a modified OrderedDictionary.",
 Environment.NewLine);
 DisplayContents(keyCollection, valueCollection, myOrderedDictionary.Count);

 // Clear the OrderedDictionary and add new values
 myOrderedDictionary.Clear();
 myOrderedDictionary.Add("newKey1", "newValue1");
 myOrderedDictionary.Add("newKey2", "newValue2");
 myOrderedDictionary.Add("newKey3", "newValue3");

 // Display the contents of the "new" Dictionary using an enumerator
 IDictionaryEnumerator myEnumerator =
 myOrderedDictionary.GetEnumerator();

 Console.WriteLine(
 "{0}Displaying the entries of a \"new\" OrderedDictionary.",
 Environment.NewLine);

 DisplayEnumerator(myEnumerator);
 }

 // Displays the contents of the OrderedDictionary from its keys and values
 public static void DisplayContents(
 ICollection keyCollection, ICollection valueCollection, int dictionarySize)
 {
 String[] myKeys = new String[dictionarySize];
 String[] myValues = new String[dictionarySize];
 keyCollection.CopyTo(myKeys, 0);
 valueCollection.CopyTo(myValues, 0);

 // Displays the contents of the OrderedDictionary
 Console.WriteLine(" INDEX KEY VALUE");
 for (int i = 0; i < dictionarySize; i++)
 {
 Console.WriteLine(" {0,-5} {1,-25} {2}",
 i, myKeys[i], myValues[i]);
 }
 Console.WriteLine();
 }

 // Displays the contents of the OrderedDictionary using its enumerator
 public static void DisplayEnumerator(IDictionaryEnumerator myEnumerator)
 {
 Console.WriteLine(" KEY VALUE");
 while (myEnumerator.MoveNext())
 {
 Console.WriteLine(" {0,-25} {1}",
 myEnumerator.Key, myEnumerator.Value);
 }
 }
}

/*
This code produces the following output.

 INDEX KEY VALUE
 0 testKey1 testValue1
 1 testKey2 testValue2
 2 keyToDelete valueToDelete
 3 testKey3 testValue3


Displaying the entries of a modified OrderedDictionary.
 INDEX KEY VALUE
 0 insertedKey1 insertedValue1
 1 testKey1 testValue1
 2 testKey2 modifiedValue


Displaying the entries of a "new" OrderedDictionary.
 KEY VALUE
 newKey1 newValue1
 newKey2 newValue2
 newKey3 newValue3

*/

' The following code example enumerates the elements of a OrderedDictionary.
Imports System.Collections
Imports System.Collections.Specialized

Public Class OrderedDictionarySample

 Public Shared Sub Main()

 ' Creates and initializes a OrderedDictionary.
 Dim myOrderedDictionary As New OrderedDictionary()
 myOrderedDictionary.Add("testKey1", "testValue1")
 myOrderedDictionary.Add("testKey2", "testValue2")
 myOrderedDictionary.Add("keyToDelete", "valueToDelete")
 myOrderedDictionary.Add("testKey3", "testValue3")

 Dim keyCollection As ICollection = myOrderedDictionary.Keys
 Dim valueCollection As ICollection = myOrderedDictionary.Values

 ' Display the contents Imports the key and value collections
 DisplayContents( _
 keyCollection, valueCollection, myOrderedDictionary.Count)

 ' Modifying the OrderedDictionary
 If Not myOrderedDictionary.IsReadOnly Then

 ' Insert a new key to the beginning of the OrderedDictionary
 myOrderedDictionary.Insert(0, "insertedKey1", "insertedValue1")

 ' Modify the value of the entry with the key "testKey2"
 myOrderedDictionary("testKey2") = "modifiedValue"

 ' Remove the last entry from the OrderedDictionary: "testKey3"
 myOrderedDictionary.RemoveAt(myOrderedDictionary.Count - 1)

 ' Remove the "keyToDelete" entry, if it exists
 If (myOrderedDictionary.Contains("keyToDelete")) Then
 myOrderedDictionary.Remove("keyToDelete")
 End If
 End If

 Console.WriteLine( _
 "{0}Displaying the entries of a modified OrderedDictionary.", _
 Environment.NewLine)
 DisplayContents( _
 keyCollection, valueCollection, myOrderedDictionary.Count)

 ' Clear the OrderedDictionary and add new values
 myOrderedDictionary.Clear()
 myOrderedDictionary.Add("newKey1", "newValue1")
 myOrderedDictionary.Add("newKey2", "newValue2")
 myOrderedDictionary.Add("newKey3", "newValue3")

 ' Display the contents of the "new" Dictionary Imports an enumerator
 Dim myEnumerator As IDictionaryEnumerator = _
 myOrderedDictionary.GetEnumerator()

 Console.WriteLine( _
 "{0}Displaying the entries of a 'new' OrderedDictionary.", _
 Environment.NewLine)

 DisplayEnumerator(myEnumerator)
 End Sub

 ' Displays the contents of the OrderedDictionary from its keys and values
 Public Shared Sub DisplayContents( _
 ByVal keyCollection As ICollection, _
 ByVal valueCollection As ICollection, ByVal dictionarySize As Integer)

 Dim myKeys(dictionarySize) As [String]
 Dim myValues(dictionarySize) As [String]
 keyCollection.CopyTo(myKeys, 0)
 valueCollection.CopyTo(myValues, 0)

 ' Displays the contents of the OrderedDictionary
 Console.WriteLine(" INDEX KEY VALUE")
 Dim i As Integer
 For i = 0 To dictionarySize - 1
 Console.WriteLine(" {0,-5} {1,-25} {2}", _
 i, myKeys(i), myValues(i))
 Next i
 Console.WriteLine()
 End Sub

 ' Displays the contents of the OrderedDictionary using its enumerator
 Public Shared Sub DisplayEnumerator( _
 ByVal myEnumerator As IDictionaryEnumerator)

 Console.WriteLine(" KEY VALUE")
 While myEnumerator.MoveNext()
 Console.WriteLine(" {0,-25} {1}", _
 myEnumerator.Key, myEnumerator.Value)
 End While
 End Sub
End Class

'This code produces the following output.
'
' INDEX KEY VALUE
'0: testKey1(testValue1)
'1: testKey2(testValue2)
'2: keyToDelete(valueToDelete)
'3: testKey3(testValue3)
'
'
'Displaying the entries of a modified OrderedDictionary.
' INDEX KEY VALUE
'0: insertedKey1(insertedValue1)
'1: testKey1(testValue1)
'2: testKey2(modifiedValue)
'
'
'Displaying the entries of a "new" OrderedDictionary.
' KEY(VALUE)
' newKey1(newValue1)
' newKey2(newValue2)
' newKey3(newValue3)

Remarks

Each element is a key/value pair stored in a DictionaryEntry object. A key cannot be null, but a value can be.

The elements of an OrderedDictionary are not sorted by the key, unlike the elements of a SortedDictionary<TKey,TValue> class. You can access elements either by the key or by the index.

The foreach statement of the C# language (For Each in Visual Basic) returns objects that are of the type of each element in the collection. Since each element of the OrderedDictionary collection is a key/value pair, the element type is not the type of the key or the type of the value. Instead, the element type is DictionaryEntry. The following code shows the syntax.

foreach (DictionaryEntry de in myOrderedDictionary)
{
 //...
}

For Each de As DictionaryEntry In myOrderedDictionary
 '...
Next de

The foreach statement is a wrapper around the enumerator, which only allows reading from, not writing to, the collection.