IList Interfaccia
Definizione
Rappresenta una raccolta non generica di oggetti a cui è possibile accedere singolarmente tramite indice.Represents a non-generic collection of objects that can be individually accessed by index.
public interface class IList : System::Collections::ICollection
public interface IList : System.Collections.ICollection
[System.Runtime.InteropServices.ComVisible(true)]
public interface IList : System.Collections.ICollection
type IList = interface
interface ICollection
interface IEnumerable
[<System.Runtime.InteropServices.ComVisible(true)>]
type IList = interface
interface ICollection
interface IEnumerable
Public Interface IList
Implements ICollection
- Derivato
- Attributi
- Implementazioni
Esempio
Nell'esempio riportato di seguito viene illustrata l'implementazione dell'interfaccia IList per creare un elenco semplice di dimensione fissa.The following example demonstrates the implementation of the IList interface to create a simple, fixed-size list.
using System;
using System.Collections;
class Program
{
static void Main()
{
var test = new SimpleList();
// Populate the List.
Console.WriteLine("Populate the List");
test.Add("one");
test.Add("two");
test.Add("three");
test.Add("four");
test.Add("five");
test.Add("six");
test.Add("seven");
test.Add("eight");
test.PrintContents();
Console.WriteLine();
// Remove elements from the list.
Console.WriteLine("Remove elements from the list");
test.Remove("six");
test.Remove("eight");
test.PrintContents();
Console.WriteLine();
// Add an element to the end of the list.
Console.WriteLine("Add an element to the end of the list");
test.Add("nine");
test.PrintContents();
Console.WriteLine();
// Insert an element into the middle of the list.
Console.WriteLine("Insert an element into the middle of the list");
test.Insert(4, "number");
test.PrintContents();
Console.WriteLine();
// Check for specific elements in the list.
Console.WriteLine("Check for specific elements in the list");
Console.WriteLine($"List contains \"three\": {test.Contains("three")}");
Console.WriteLine($"List contains \"ten\": {test.Contains("ten")}");
}
}
class SimpleList : IList
{
private object[] _contents = new object[8];
private int _count;
public SimpleList()
{
_count = 0;
}
// IList Members
public int Add(object value)
{
if (_count < _contents.Length)
{
_contents[_count] = value;
_count++;
return (_count - 1);
}
return -1;
}
public void Clear()
{
_count = 0;
}
public bool Contains(object value)
{
for (int i = 0; i < Count; i++)
{
if (_contents[i] == value)
{
return true;
}
}
return false;
}
public int IndexOf(object value)
{
for (int i = 0; i < Count; i++)
{
if (_contents[i] == value)
{
return i;
}
}
return -1;
}
public void Insert(int index, object value)
{
if ((_count + 1 <= _contents.Length) && (index < Count) && (index >= 0))
{
_count++;
for (int i = Count - 1; i > index; i--)
{
_contents[i] = _contents[i - 1];
}
_contents[index] = value;
}
}
public bool IsFixedSize
{
get
{
return true;
}
}
public bool IsReadOnly
{
get
{
return false;
}
}
public void Remove(object value)
{
RemoveAt(IndexOf(value));
}
public void RemoveAt(int index)
{
if ((index >= 0) && (index < Count))
{
for (int i = index; i < Count - 1; i++)
{
_contents[i] = _contents[i + 1];
}
_count--;
}
}
public object this[int index]
{
get
{
return _contents[index];
}
set
{
_contents[index] = value;
}
}
// ICollection members.
public void CopyTo(Array array, int index)
{
for (int i = 0; i < Count; i++)
{
array.SetValue(_contents[i], index++);
}
}
public int Count
{
get
{
return _count;
}
}
public bool IsSynchronized
{
get
{
return false;
}
}
// Return the current instance since the underlying store is not
// publicly available.
public object SyncRoot
{
get
{
return this;
}
}
// IEnumerable Members
public IEnumerator GetEnumerator()
{
// Refer to the IEnumerator documentation for an example of
// implementing an enumerator.
throw new NotImplementedException("The method or operation is not implemented.");
}
public void PrintContents()
{
Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.");
Console.Write("List contents:");
for (int i = 0; i < Count; i++)
{
Console.Write($" {_contents[i]}");
}
Console.WriteLine();
}
}
// This code produces output similar to the following:
// Populate the List:
// List has a capacity of 8 and currently has 8 elements.
// List contents: one two three four five six seven eight
//
// Remove elements from the list:
// List has a capacity of 8 and currently has 6 elements.
// List contents: one two three four five seven
//
// Add an element to the end of the list:
// List has a capacity of 8 and currently has 7 elements.
// List contents: one two three four five seven nine
//
// Insert an element into the middle of the list:
// List has a capacity of 8 and currently has 8 elements.
// List contents: one two three four number five seven nine
//
// Check for specific elements in the list:
// List contains "three": True
// List contains "ten": False
Imports System.Collections
Public Class Program
Shared Sub Main()
Dim myList As New SimpleList()
' Populate the List.
Console.WriteLine("Populate the List")
myList.Add("one")
myList.Add("two")
myList.Add("three")
myList.Add("four")
myList.Add("five")
myList.Add("six")
myList.Add("seven")
myList.Add("eight")
myList.PrintContents()
Console.WriteLine()
' Remove elements from the list.
Console.WriteLine("Remove elements from the list")
myList.Remove("six")
myList.Remove("eight")
myList.PrintContents()
Console.WriteLine()
' Add an element to the end of the list.
Console.WriteLine("Add an element to the end of the list")
myList.Add("nine")
myList.PrintContents()
Console.WriteLine()
' Insert an element into the middle of the list.
Console.WriteLine("Insert an element into the middle of the list")
myList.Insert(4, "number")
myList.PrintContents()
Console.WriteLine()
' Check for specific elements in the list.
Console.WriteLine("Check for specific elements in the list")
Console.WriteLine($"List contains 'three': {myList.Contains("three")}")
Console.WriteLine($"List contains 'ten': {myList.Contains("ten")}")
End Sub
End Class
Public Class SimpleList
Implements IList
Private _contents(7) As Object
Private _count As Integer
Public Sub New()
_count = 0
End Sub
' IList members.
Public Function Add(ByVal value As Object) As Integer Implements IList.Add
If _count < _contents.Length Then
_contents(_count) = value
_count += 1
Return _count - 1
End If
Return -1
End Function
Public Sub Clear() Implements IList.Clear
_count = 0
End Sub
Public Function Contains(ByVal value As Object) As Boolean Implements IList.Contains
For i As Integer = 0 To Count - 1
If _contents(i) = value Then Return True
Next
Return False
End Function
Public Function IndexOf(ByVal value As Object) As Integer Implements IList.IndexOf
For i As Integer = 0 To Count - 1
If _contents(i) = value Then Return i
Next
Return -1
End Function
Public Sub Insert(ByVal index As Integer, ByVal value As Object) Implements IList.Insert
If _count + 1 <= _contents.Length AndAlso index < Count AndAlso index >= 0 Then
_count += 1
For i As Integer = Count - 1 To index Step -1
_contents(i) = _contents(i - 1)
Next
_contents(index) = value
End If
End Sub
Public ReadOnly Property IsFixedSize() As Boolean Implements IList.IsFixedSize
Get
Return True
End Get
End Property
Public ReadOnly Property IsReadOnly() As Boolean Implements IList.IsReadOnly
Get
Return False
End Get
End Property
Public Sub Remove(ByVal value As Object) Implements IList.Remove
RemoveAt(IndexOf(value))
End Sub
Public Sub RemoveAt(ByVal index As Integer) Implements IList.RemoveAt
if index >= 0 AndAlso index < Count Then
for i As Integer = index To Count - 2
_contents(i) = _contents(i + 1)
Next
_count -= 1
End If
End Sub
Public Property Item(ByVal index As Integer) As Object Implements IList.Item
Get
Return _contents(index)
End Get
Set(ByVal value As Object)
_contents(index) = value
End Set
End Property
' ICollection members.
Public Sub CopyTo(ByVal array As Array, ByVal index As Integer) Implements ICollection.CopyTo
For i As Integer = 0 To Count - 1
array.SetValue(_contents(i), index)
index += 1
Next
End Sub
Public ReadOnly Property Count() As Integer Implements ICollection.Count
Get
Return _count
End Get
End Property
Public ReadOnly Property IsSynchronized() As Boolean Implements ICollection.IsSynchronized
Get
Return False
End Get
End Property
' Return the current instance since the underlying store is not
' publicly available.
Public ReadOnly Property SyncRoot() As Object Implements ICollection.SyncRoot
Get
Return Me
End Get
End Property
' IEnumerable members.
Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
' Refer to the IEnumerator documentation for an example of
' implementing an enumerator.
Throw New NotImplementedException("The method or operation is not implemented.")
End Function
Public Sub PrintContents()
Console.WriteLine($"List has a capacity of {_contents.Length} and currently has {_count} elements.")
Console.Write("List contents:")
For i As Integer = 0 To Count - 1
Console.Write($" {_contents(i)}")
Next
Console.WriteLine()
End Sub
End Class
' This code produces output similar to the following:
' Populate the List:
' List has a capacity of 8 and currently has 8 elements.
' List contents: one two three four five six seven eight
'
' Remove elements from the list:
' List has a capacity of 8 and currently has 6 elements.
' List contents: one two three four five seven
'
' Add an element to the end of the list:
' List has a capacity of 8 and currently has 7 elements.
' List contents: one two three four five seven nine
'
' Insert an element into the middle of the list:
' List has a capacity of 8 and currently has 8 elements.
' List contents: one two three four number five seven nine
'
' Check for specific elements in the list:
' List contains "three": True
' List contains "ten": False
Commenti
IList è un discendente dell' ICollection interfaccia e è l'interfaccia di base di tutti gli elenchi non generici.IList is a descendant of the ICollection interface and is the base interface of all non-generic lists. IList le implementazioni rientrano in tre categorie: di sola lettura, a dimensione fissa e a dimensione variabile.IList implementations fall into three categories: read-only, fixed-size, and variable-size. Non è possibile modificare un oggetto di sola lettura IList .A read-only IList cannot be modified. Una dimensione fissa non IList consente l'aggiunta o la rimozione di elementi, ma consente la modifica degli elementi esistenti.A fixed-size IList does not allow the addition or removal of elements, but it allows the modification of existing elements. Una variabile-size IList consente l'aggiunta, la rimozione e la modifica degli elementi.A variable-size IList allows the addition, removal, and modification of elements.
Per la versione generica di questa interfaccia, vedere System.Collections.Generic.IList<T> .For the generic version of this interface, see System.Collections.Generic.IList<T>.
Proprietà
Count |
Ottiene il numero di elementi contenuti in ICollection.Gets the number of elements contained in the ICollection. (Ereditato da ICollection) |
IsFixedSize |
Ottiene un valore che indica se IList ha dimensioni fisse.Gets a value indicating whether the IList has a fixed size. |
IsReadOnly |
Ottiene un valore che indica se IList è di sola lettura.Gets a value indicating whether the IList is read-only. |
IsSynchronized |
Ottiene un valore che indica se l'accesso a ICollection è sincronizzato (thread-safe).Gets a value indicating whether access to the ICollection is synchronized (thread safe). (Ereditato da ICollection) |
Item[Int32] |
Ottiene o imposta l'elemento in corrispondenza dell'indice specificato.Gets or sets the element at the specified index. |
SyncRoot |
Ottiene un oggetto che può essere usato per sincronizzare l'accesso a ICollection.Gets an object that can be used to synchronize access to the ICollection. (Ereditato da ICollection) |
Metodi
Add(Object) | |
Clear() |
Rimuove tutti gli elementi da IList.Removes all items from the IList. |
Contains(Object) |
Stabilisce se IList contiene un valore specifico.Determines whether the IList contains a specific value. |
CopyTo(Array, Int32) |
Copia gli elementi di ICollection in Array a partire da un particolare indice Array.Copies the elements of the ICollection to an Array, starting at a particular Array index. (Ereditato da ICollection) |
GetEnumerator() |
Restituisce un enumeratore che consente di eseguire l'iterazione di una raccolta.Returns an enumerator that iterates through a collection. (Ereditato da IEnumerable) |
IndexOf(Object) |
Determina l'indice di un elemento specifico in IList.Determines the index of a specific item in the IList. |
Insert(Int32, Object) |
Inserisce un elemento in IList in corrispondenza dell'indice specificato.Inserts an item to the IList at the specified index. |
Remove(Object) |
Rimuove la prima occorrenza di un oggetto specifico da IList.Removes the first occurrence of a specific object from the IList. |
RemoveAt(Int32) |
Rimuove l'elemento IList in corrispondenza dell'indice specificato.Removes the IList item at the specified index. |
Metodi di estensione
Cast<TResult>(IEnumerable) |
Esegue il cast degli elementi di un oggetto IEnumerable nel tipo specificato.Casts the elements of an IEnumerable to the specified type. |
OfType<TResult>(IEnumerable) |
Filtra gli elementi di un oggetto IEnumerable in base a un tipo specificato.Filters the elements of an IEnumerable based on a specified type. |
AsParallel(IEnumerable) |
Consente la parallelizzazione di una query.Enables parallelization of a query. |
AsQueryable(IEnumerable) |
Converte un oggetto IEnumerable in un oggetto IQueryable.Converts an IEnumerable to an IQueryable. |