IOrderedDictionary Interface
Definition
Important
Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.
Represents an indexed collection of key/value pairs.
public interface class IOrderedDictionary : System::Collections::IDictionarypublic interface IOrderedDictionary : System.Collections.IDictionarytype IOrderedDictionary = interface
interface ICollection
interface IEnumerable
interface IDictionarytype IOrderedDictionary = interface
interface IDictionary
interface ICollection
interface IEnumerablePublic Interface IOrderedDictionary
Implements IDictionary- Derived
- Implements
Examples
The following code example demonstrates the implementation of a simple IOrderedDictionary based on the ArrayList class. The implemented IOrderedDictionary stores first names as the keys and last names as the values, with the added requirement that each first name is unique.
#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
public ref class PeopleEnum : IDictionaryEnumerator
{
private:
// Enumerators are positioned before the first element
// until the first MoveNext() call.
int position;
ArrayList^ _people;
public:
PeopleEnum(ArrayList^ list)
{
this->Reset();
_people = list;
}
virtual bool MoveNext()
{
position++;
return (position < _people->Count);
}
virtual void Reset()
{
position = -1;
}
virtual property Object^ Current
{
Object^ get()
{
try
{
return _people[position];
}
catch (IndexOutOfRangeException^)
{
throw gcnew InvalidOperationException();
}
}
}
virtual property DictionaryEntry Entry
{
DictionaryEntry get()
{
return (DictionaryEntry)(Current);
}
}
virtual property Object^ Key
{
Object^ get()
{
try
{
return ((DictionaryEntry^)_people[position])->Key;
}
catch (IndexOutOfRangeException^)
{
throw gcnew InvalidOperationException();
}
}
}
virtual property Object^ Value
{
Object^ get()
{
try
{
return ((DictionaryEntry^)_people[position])->Value;
}
catch (IndexOutOfRangeException^)
{
throw gcnew InvalidOperationException();
}
}
}
};
public ref class People : IOrderedDictionary
{
private:
ArrayList^ _people;
public:
People(int numItems)
{
_people = gcnew ArrayList(numItems);
}
int IndexOfKey(Object^ key)
{
for (int i = 0; i < _people->Count; i++)
{
if (((DictionaryEntry^)_people[i])->Key == key)
return i;
}
// key not found, return -1.
return -1;
}
virtual property Object^ default[Object^]
{
Object^ get(Object^ key)
{
return ((DictionaryEntry^)_people[IndexOfKey(key)])->Value;
}
void set(Object^ key, Object^ value)
{
_people[IndexOfKey(key)] = gcnew DictionaryEntry(key, value);
}
}
// IOrderedDictionary Members
virtual IDictionaryEnumerator^ GetEnumerator()
{
return gcnew PeopleEnum(_people);
}
virtual void Insert(int index, Object^ key, Object^ value)
{
if (IndexOfKey(key) != -1)
{
throw gcnew ArgumentException("An element with the same key already exists in the collection.");
}
_people->Insert(index, gcnew DictionaryEntry(key, value));
}
virtual void RemoveAt(int index)
{
_people->RemoveAt(index);
}
virtual property Object^ default[int]
{
Object^ get(int index)
{
return ((DictionaryEntry^)_people[index])->Value;
}
void set(int index, Object^ value)
{
Object^ key = ((DictionaryEntry^)_people[index])->Key;
_people[index] = gcnew DictionaryEntry(key, value);
}
}
// IDictionary Members
virtual void Add(Object^ key, Object^ value)
{
if (IndexOfKey(key) != -1)
{
throw gcnew ArgumentException("An element with the same key already exists in the collection.");
}
_people->Add(gcnew DictionaryEntry(key, value));
}
virtual void Clear()
{
_people->Clear();
}
virtual bool Contains(Object^ key)
{
if (IndexOfKey(key) == -1)
{
return false;
}
else
{
return true;
}
}
virtual property bool IsFixedSize
{
bool get()
{
return false;
}
}
virtual property bool IsReadOnly
{
bool get()
{
return false;
}
}
virtual property ICollection^ Keys
{
ICollection^ get()
{
ArrayList^ KeyCollection = gcnew ArrayList(_people->Count);
for (int i = 0; i < _people->Count; i++)
{
KeyCollection->Add( ((DictionaryEntry^)_people[i])->Key );
}
return KeyCollection;
}
}
virtual void Remove(Object^ key)
{
_people->RemoveAt(IndexOfKey(key));
}
virtual property ICollection^ Values
{
ICollection ^get()
{
ArrayList^ ValueCollection = gcnew ArrayList(_people->Count);
for (int i = 0; i < _people->Count; i++)
{
ValueCollection->Add( ((DictionaryEntry^)_people[i])->Value );
}
return ValueCollection;
}
}
// ICollection Members
virtual void CopyTo(Array^ array, int index)
{
_people->CopyTo(array, index);
}
virtual property int Count
{
int get()
{
return _people->Count;
}
}
virtual property bool IsSynchronized
{
bool get()
{
return _people->IsSynchronized;
}
}
virtual property Object^ SyncRoot
{
Object^ get()
{
return _people->SyncRoot;
}
}
// IEnumerable Members
virtual IEnumerator^ IfcGetEnumerator() = IEnumerable::GetEnumerator
{
return (IEnumerator^) gcnew PeopleEnum(_people);
}
};
class App
{
public:
static void Main()
{
People^ peopleCollection = gcnew People(3);
peopleCollection->Add("John", "Smith");
peopleCollection->Add("Jim", "Johnson");
peopleCollection->Add("Sue", "Rabon");
Console::WriteLine("Displaying the entries in peopleCollection:");
for each (DictionaryEntry^ de in peopleCollection)
{
Console::WriteLine("{0} {1}", de->Key, de->Value);
}
Console::WriteLine();
Console::WriteLine("Displaying the entries in the modified peopleCollection:");
peopleCollection["Jim"] = "Jackson";
peopleCollection->Remove("Sue");
peopleCollection->Insert(0, "Fred", "Anderson");
for each (DictionaryEntry^ de in peopleCollection)
{
Console::WriteLine("{0} {1}", de->Key, de->Value);
}
}
};
int main()
{
App::Main();
}
/* This code produces output similar to the following:
*
* Displaying the entries in peopleCollection:
* John Smith
* Jim Johnson
* Sue Rabon
*
* Displaying the entries in the modified peopleCollection:
* Fred Anderson
* John Smith
* Jim Jackson
*/
using System;
using System.Collections;
using System.Collections.Specialized;
public class People : IOrderedDictionary
{
private ArrayList _people;
public People(int numItems)
{
_people = new ArrayList(numItems);
}
public int IndexOfKey(object key)
{
for (int i = 0; i < _people.Count; i++)
{
if (((DictionaryEntry)_people[i]).Key == key)
return i;
}
// key not found, return -1.
return -1;
}
public object this[object key]
{
get
{
return ((DictionaryEntry)_people[IndexOfKey(key)]).Value;
}
set
{
_people[IndexOfKey(key)] = new DictionaryEntry(key, value);
}
}
// IOrderedDictionary Members
public IDictionaryEnumerator GetEnumerator()
{
return new PeopleEnum(_people);
}
public void Insert(int index, object key, object value)
{
if (IndexOfKey(key) != -1)
{
throw new ArgumentException("An element with the same key already exists in the collection.");
}
_people.Insert(index, new DictionaryEntry(key, value));
}
public void RemoveAt(int index)
{
_people.RemoveAt(index);
}
public object this[int index]
{
get
{
return ((DictionaryEntry)_people[index]).Value;
}
set
{
object key = ((DictionaryEntry)_people[index]).Key;
_people[index] = new DictionaryEntry(key, value);
}
}
// IDictionary Members
public void Add(object key, object value)
{
if (IndexOfKey(key) != -1)
{
throw new ArgumentException("An element with the same key already exists in the collection.");
}
_people.Add(new DictionaryEntry(key, value));
}
public void Clear()
{
_people.Clear();
}
public bool Contains(object key)
{
if (IndexOfKey(key) == -1)
{
return false;
}
else
{
return true;
}
}
public bool IsFixedSize
{
get
{
return false;
}
}
public bool IsReadOnly
{
get
{
return false;
}
}
public ICollection Keys
{
get
{
ArrayList KeyCollection = new ArrayList(_people.Count);
for (int i = 0; i < _people.Count; i++)
{
KeyCollection.Add( ((DictionaryEntry)_people[i]).Key );
}
return KeyCollection;
}
}
public void Remove(object key)
{
_people.RemoveAt(IndexOfKey(key));
}
public ICollection Values
{
get
{
ArrayList ValueCollection = new ArrayList(_people.Count);
for (int i = 0; i < _people.Count; i++)
{
ValueCollection.Add( ((DictionaryEntry)_people[i]).Value );
}
return ValueCollection;
}
}
// ICollection Members
public void CopyTo(Array array, int index)
{
_people.CopyTo(array, index);
}
public int Count
{
get
{
return _people.Count;
}
}
public bool IsSynchronized
{
get
{
return _people.IsSynchronized;
}
}
public object SyncRoot
{
get
{
return _people.SyncRoot;
}
}
// IEnumerable Members
IEnumerator IEnumerable.GetEnumerator()
{
return new PeopleEnum(_people);
}
}
public class PeopleEnum : IDictionaryEnumerator
{
public ArrayList _people;
// Enumerators are positioned before the first element
// until the first MoveNext() call.
int position = -1;
public PeopleEnum(ArrayList list)
{
_people = list;
}
public bool MoveNext()
{
position++;
return (position < _people.Count);
}
public void Reset()
{
position = -1;
}
public object Current
{
get
{
try
{
return _people[position];
}
catch (IndexOutOfRangeException)
{
throw new InvalidOperationException();
}
}
}
public DictionaryEntry Entry
{
get
{
return (DictionaryEntry)Current;
}
}
public object Key
{
get
{
try
{
return ((DictionaryEntry)_people[position]).Key;
}
catch (IndexOutOfRangeException)
{
throw new InvalidOperationException();
}
}
}
public object Value
{
get
{
try
{
return ((DictionaryEntry)_people[position]).Value;
}
catch (IndexOutOfRangeException)
{
throw new InvalidOperationException();
}
}
}
}
class App
{
static void Main()
{
People peopleCollection = new People(3);
peopleCollection.Add("John", "Smith");
peopleCollection.Add("Jim", "Johnson");
peopleCollection.Add("Sue", "Rabon");
Console.WriteLine("Displaying the entries in peopleCollection:");
foreach (DictionaryEntry de in peopleCollection)
{
Console.WriteLine("{0} {1}", de.Key, de.Value);
}
Console.WriteLine();
Console.WriteLine("Displaying the entries in the modified peopleCollection:");
peopleCollection["Jim"] = "Jackson";
peopleCollection.Remove("Sue");
peopleCollection.Insert(0, "Fred", "Anderson");
foreach (DictionaryEntry de in peopleCollection)
{
Console.WriteLine("{0} {1}", de.Key, de.Value);
}
}
}
/* This code produces output similar to the following:
*
* Displaying the entries in peopleCollection:
* John Smith
* Jim Johnson
* Sue Rabon
*
* Displaying the entries in the modified peopleCollection:
* Fred Anderson
* John Smith
* Jim Jackson
*/
Imports System.Collections
Imports System.Collections.Specialized
Public Class People
Implements IOrderedDictionary
Private _people As ArrayList
Public Sub New(ByVal numItems As Integer)
_people = New ArrayList(numItems)
End Sub
Public Function IndexOfKey(ByVal key As Object) As Integer
Dim i As Integer
For i = 0 To _people.Count - 1
If CType(_people(i), DictionaryEntry).Key = key Then
Return i
End If
Next i
' key not found, return -1.
Return -1
End Function
' IOrderedDictionary Members
Public Function GetEnumerator() As IDictionaryEnumerator _
Implements IOrderedDictionary.GetEnumerator
Return New PeopleEnum(_people)
End Function
Public Sub Insert(ByVal index As Integer, ByVal key As Object, _
ByVal value As Object) Implements IOrderedDictionary.Insert
If Not IndexOfKey(key) = -1 Then
Throw New ArgumentException("An element with the same key already exists in the collection.")
End If
_people.Insert(index, New DictionaryEntry(key, value))
End Sub
Public Sub RemoveAt(ByVal index As Integer) _
Implements IOrderedDictionary.RemoveAt
_people.RemoveAt(index)
End Sub
Public Property Item(ByVal index As Integer) As Object _
Implements IOrderedDictionary.Item
Get
Return CType(_people(index), DictionaryEntry).Value
End Get
Set(ByVal value As Object)
Dim key As Object = CType(_people(index), DictionaryEntry).Key
_people(index) = New DictionaryEntry(key, value)
End Set
End Property
' IDictionary Members
Public Function IDictionaryGetEnumerator() As IDictionaryEnumerator _
Implements IDictionary.GetEnumerator
Return New PeopleEnum(_people)
End Function
Public Property Item(ByVal key As Object) As Object _
Implements IDictionary.Item
Get
Return CType(_people(IndexOfKey(key)), DictionaryEntry).Value
End Get
Set(ByVal value)
_people(IndexOfKey(key)) = New DictionaryEntry(key, value)
End Set
End Property
Public Sub Add(ByVal key As Object, ByVal value As Object) _
Implements IDictionary.Add
If Not IndexOfKey(key) = -1 Then
Throw New ArgumentException("An element with the same key already exists in the collection.")
End If
_people.Add(New DictionaryEntry(key, value))
End Sub
Public Sub Clear() Implements IDictionary.Clear
_people.Clear()
End Sub
Public Function Contains(ByVal key As Object) As Boolean _
Implements IDictionary.Contains
If IndexOfKey(key) = -1 Then
Return False
Else
Return True
End If
End Function
Public ReadOnly Property IsFixedSize() As Boolean _
Implements IDictionary.IsFixedSize
Get
Return False
End Get
End Property
Public ReadOnly Property IsReadOnly() As Boolean _
Implements IDictionary.IsReadOnly
Get
Return False
End Get
End Property
Public ReadOnly Property Keys() As ICollection _
Implements IDictionary.Keys
Get
Dim KeyCollection As ArrayList = New ArrayList(_people.Count)
Dim i As Integer
For i = 0 To _people.Count - 1
KeyCollection.Add( CType(_people(i), DictionaryEntry).Key )
Next i
Return KeyCollection
End Get
End Property
Public Sub Remove(ByVal key As Object) _
Implements IDictionary.Remove
_people.RemoveAt(IndexOfKey(key))
End Sub
Public ReadOnly Property Values() As ICollection _
Implements IDictionary.Values
Get
Dim ValueCollection As ArrayList = New ArrayList(_people.Count)
Dim i As Integer
For i = 0 To _people.Count - 1
ValueCollection.Add( CType(_people(i), DictionaryEntry).Value )
Next i
Return ValueCollection
End Get
End Property
' ICollection Members
Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) _
Implements ICollection.CopyTo
_people.CopyTo(Array, index)
End Sub
Public ReadOnly Property Count() As Integer _
Implements ICollection.Count
Get
Return _people.Count
End Get
End Property
Public ReadOnly Property IsSynchronized() As Boolean _
Implements ICollection.IsSynchronized
Get
Return _people.IsSynchronized
End Get
End Property
Public ReadOnly Property SyncRoot() As Object _
Implements ICollection.SyncRoot
Get
Return _people.SyncRoot
End Get
End Property
' IEnumerable Members
Public Function IEnumerableGetEnumerator() As IEnumerator _
Implements IEnumerable.GetEnumerator
Return New PeopleEnum(_people)
End Function
End Class
Public Class PeopleEnum
Implements IDictionaryEnumerator
Public _people As ArrayList
' Enumerators are positioned before the first element
' until the first MoveNext() call.
Dim position As Integer = -1
Public Sub New(ByVal list As ArrayList)
_people = list
End Sub
Public Function MoveNext() As Boolean _
Implements IEnumerator.MoveNext
position = position + 1
Return (position < _people.Count)
End Function
Public Sub Reset() _
Implements IEnumerator.Reset
position = -1
End Sub
Public ReadOnly Property Current() As Object _
Implements IEnumerator.Current
Get
Try
Return _people(position)
Catch e As IndexOutOfRangeException
Throw New InvalidOperationException()
End Try
End Get
End Property
Public ReadOnly Property Entry() As DictionaryEntry _
Implements IDictionaryEnumerator.Entry
Get
Return CType(Current, DictionaryEntry)
End Get
End Property
Public ReadOnly Property Key() As Object _
Implements IDictionaryEnumerator.Key
Get
Try
Return CType(_people(position), DictionaryEntry).Key
Catch e As IndexOutOfRangeException
Throw New InvalidOperationException()
End Try
End Get
End Property
Public ReadOnly Property Value() As Object _
Implements IDictionaryEnumerator.Value
Get
Try
Return CType(_people(position), DictionaryEntry).Value
Catch e As IndexOutOfRangeException
Throw New InvalidOperationException()
End Try
End Get
End Property
End Class
Class App
Shared Sub Main()
Dim peopleCollection As People = New People(3)
peopleCollection.Add("John", "Smith")
peopleCollection.Add("Jim", "Johnson")
peopleCollection.Add("Sue", "Rabon")
Console.WriteLine("Displaying the entries in peopleCollection:")
Dim de As DictionaryEntry
For Each de In peopleCollection
Console.WriteLine("{0} {1}", de.Key, de.Value)
Next
Console.WriteLine()
Console.WriteLine("Displaying the entries in the modified peopleCollection:")
'peopleCollection("Jim") = "Jackson"
peopleCollection.Remove("Sue")
peopleCollection.Insert(0, "Fred", "Anderson")
For Each de In peopleCollection
Console.WriteLine("{0} {1}", de.Key, de.Value)
Next
End Sub
End Class
' This code produces output similar to the following:
'
' Displaying the entries in peopleCollection:
' John Smith
' Jim Johnson
' Sue Rabon
'
' Displaying the entries in the modified peopleCollection:
' Fred Anderson
' John Smith
' Jim Jackson
Remarks
IOrderedDictionary elements can be accessed either with the key or with the index.
Each element is a key/value pair stored in a DictionaryEntry structure.
Each pair must have a unique key that is not null, but the value can be null and does not have to be unique. The IOrderedDictionary interface allows the contained keys and values to be enumerated, but it does not imply any particular sort order.
The foreach statement of the C# language (For Each in Visual Basic) returns an object of the type of the elements in the collection. Because each element of the IDictionary 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, as the following example shows.
for each (DictionaryEntry de in myOrderedDictionary)
{
//...
}
foreach (DictionaryEntry de in myOrderedDictionary)
{
//...
}
For Each de In myOrderedDictionary
'...
Next
The foreach statement is a wrapper around the enumerator, which allows only reading from, not writing to, the collection.
Notes to Implementers
The implementing class must have a means to compare keys.
Properties
| Count |
Gets the number of elements contained in the ICollection. (Inherited from ICollection) |
| IsFixedSize |
Gets a value indicating whether the IDictionary object has a fixed size. (Inherited from IDictionary) |
| IsReadOnly |
Gets a value indicating whether the IDictionary object is read-only. (Inherited from IDictionary) |
| IsSynchronized |
Gets a value indicating whether access to the ICollection is synchronized (thread safe). (Inherited from ICollection) |
| Item[Int32] |
Gets or sets the element at the specified index. |
| Item[Object] |
Gets or sets the element with the specified key. (Inherited from IDictionary) |
| Keys |
Gets an ICollection object containing the keys of the IDictionary object. (Inherited from IDictionary) |
| SyncRoot |
Gets an object that can be used to synchronize access to the ICollection. (Inherited from ICollection) |
| Values |
Gets an ICollection object containing the values in the IDictionary object. (Inherited from IDictionary) |
Methods
| Add(Object, Object) |
Adds an element with the provided key and value to the IDictionary object. (Inherited from IDictionary) |
| Clear() |
Removes all elements from the IDictionary object. (Inherited from IDictionary) |
| Contains(Object) |
Determines whether the IDictionary object contains an element with the specified key. (Inherited from IDictionary) |
| CopyTo(Array, Int32) |
Copies the elements of the ICollection to an Array, starting at a particular Array index. (Inherited from ICollection) |
| GetEnumerator() |
Returns an enumerator that iterates through the IOrderedDictionary collection. |
| Insert(Int32, Object, Object) |
Inserts a key/value pair into the collection at the specified index. |
| Remove(Object) |
Removes the element with the specified key from the IDictionary object. (Inherited from IDictionary) |
| RemoveAt(Int32) |
Removes the element at the specified index. |
Extension Methods
| Cast<TResult>(IEnumerable) |
Casts the elements of an IEnumerable to the specified type. |
| OfType<TResult>(IEnumerable) |
Filters the elements of an IEnumerable based on a specified type. |
| AsParallel(IEnumerable) |
Enables parallelization of a query. |
| AsQueryable(IEnumerable) |
Converts an IEnumerable to an IQueryable. |
Applies to
See also
Tee yhteistyötä kanssamme GitHubissa
Tämän sisällön lähde on GitHubissa, jossa voit myös luoda ja tarkastella ongelmia ja pull-pyyntöjä. Katso lisätietoja osallistujan oppaasta.
