Represents a collection of key/value pairs that are accessible by the key or index.
Namespace: System.Collections.Specialized
Assembly: System (in system.dll)
Visual Basic (Declaration)
<SerializableAttribute> _
Public Class OrderedDictionary
Implements IOrderedDictionary, IDictionary, ICollection, IEnumerable, _
ISerializable, IDeserializationCallback
Dim instance As OrderedDictionary
[SerializableAttribute]
public class OrderedDictionary : IOrderedDictionary, IDictionary, ICollection,
IEnumerable, ISerializable, IDeserializationCallback
[SerializableAttribute]
public ref class OrderedDictionary : IOrderedDictionary, IDictionary, ICollection,
IEnumerable, ISerializable, IDeserializationCallback
/** @attribute SerializableAttribute() */
public class OrderedDictionary implements IOrderedDictionary, IDictionary,
ICollection, IEnumerable, ISerializable, IDeserializationCallback
SerializableAttribute
public class OrderedDictionary implements IOrderedDictionary, IDictionary,
ICollection, IEnumerable, ISerializable, IDeserializationCallback
Each element is a key/value pair stored in a DictionaryEntry object. A key cannot be a null reference (Nothing in Visual Basic), but a value can be.
The elements of an OrderedDictionary are not sorted in any way. OrderedDictionary collections allow access by both index as well as key.
The foreach statement of the C# language (For Each in Visual Basic) requires 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 C# and Visual Basic syntax.
foreach (DictionaryEntry de in myListDictionary) {...}
For Each de As DictionaryEntry In myListDictionary
...
Next de
The foreach statement is a wrapper around the enumerator, which only allows reading from, not writing to, the collection.
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.
Imports System
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)
Console.ReadLine()
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)
// 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);
Console.ReadLine();
}
// 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
*/
System.Object
System.Collections.Specialized.OrderedDictionary
System.Web.Configuration.AdapterDictionary
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.
.NET Framework
Supported in: 3.0, 2.0