ArrayList.Insert(Int32, Object) Metoda
Definice
Důležité
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Vloží prvek do zadaného indexu ArrayList .
public:
virtual void Insert(int index, System::Object ^ value);
public virtual void Insert (int index, object value);
public virtual void Insert (int index, object? value);
abstract member Insert : int * obj -> unit
override this.Insert : int * obj -> unit
Public Overridable Sub Insert (index As Integer, value As Object)
Parametry
- index
- Int32
Index založený na nule, do kterého se má položka value
vložit
Implementuje
Výjimky
Příklady
Následující příklad kódu ukazuje, jak vložit elementy ArrayListdo .
using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList );
int main()
{
// Creates and initializes a new ArrayList using Insert instead of Add.
ArrayList^ myAL = gcnew ArrayList;
myAL->Insert( 0, "The" );
myAL->Insert( 1, "fox" );
myAL->Insert( 2, "jumps" );
myAL->Insert( 3, "over" );
myAL->Insert( 4, "the" );
myAL->Insert( 5, "dog" );
// Creates and initializes a new Queue.
Queue^ myQueue = gcnew Queue;
myQueue->Enqueue( "quick" );
myQueue->Enqueue( "brown" );
// Displays the ArrayList and the Queue.
Console::WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL );
Console::WriteLine( "The Queue initially contains the following:" );
PrintValues( myQueue );
// Copies the Queue elements to the ArrayList at index 1.
myAL->InsertRange( 1, myQueue );
// Displays the ArrayList.
Console::WriteLine( "After adding the Queue, the ArrayList now contains:" );
PrintValues( myAL );
// Search for "dog" and add "lazy" before it.
myAL->Insert( myAL->IndexOf( "dog" ), "lazy" );
// Displays the ArrayList.
Console::WriteLine( "After adding \"lazy\", the ArrayList now contains:" );
PrintValues( myAL );
// Add "!!!" at the end.
myAL->Insert( myAL->Count, "!!!" );
// Displays the ArrayList.
Console::WriteLine( "After adding \"!!!\", the ArrayList now contains:" );
PrintValues( myAL );
// Inserting an element beyond Count throws an exception.
try
{
myAL->Insert( myAL->Count + 1, "anystring" );
}
catch ( Exception^ myException )
{
Console::WriteLine( "Exception: {0}", myException );
}
}
void PrintValues( IEnumerable^ myList )
{
IEnumerator^ myEnum = myList->GetEnumerator();
while ( myEnum->MoveNext() )
{
Object^ obj = safe_cast<Object^>(myEnum->Current);
Console::Write( " {0}", obj );
}
Console::WriteLine();
}
/*
This code produces the following output.
The ArrayList initially contains the following:
The fox jumps over the dog
The Queue initially contains the following:
quick brown
After adding the Queue, the ArrayList now contains:
The quick brown fox jumps over the dog
After adding "lazy", the ArrayList now contains:
The quick brown fox jumps over the lazy dog
After adding "!!!", the ArrayList now contains:
The quick brown fox jumps over the lazy dog !!!
Exception: System.ArgumentOutOfRangeException: Insertion index was out of range. Must be non-negative and less than or equal to size.
Parameter name: index
at System.Collections.ArrayList.Insert(Int32 index, Object value)
at SamplesArrayList.Main()
*/
using System;
using System.Collections;
public class SamplesArrayList {
public static void Main() {
// Creates and initializes a new ArrayList using Insert instead of Add.
ArrayList myAL = new ArrayList();
myAL.Insert( 0, "The" );
myAL.Insert( 1, "fox" );
myAL.Insert( 2, "jumps" );
myAL.Insert( 3, "over" );
myAL.Insert( 4, "the" );
myAL.Insert( 5, "dog" );
// Creates and initializes a new Queue.
Queue myQueue = new Queue();
myQueue.Enqueue( "quick" );
myQueue.Enqueue( "brown" );
// Displays the ArrayList and the Queue.
Console.WriteLine( "The ArrayList initially contains the following:" );
PrintValues( myAL );
Console.WriteLine( "The Queue initially contains the following:" );
PrintValues( myQueue );
// Copies the Queue elements to the ArrayList at index 1.
myAL.InsertRange( 1, myQueue );
// Displays the ArrayList.
Console.WriteLine( "After adding the Queue, the ArrayList now contains:" );
PrintValues( myAL );
// Search for "dog" and add "lazy" before it.
myAL.Insert( myAL.IndexOf( "dog" ), "lazy" );
// Displays the ArrayList.
Console.WriteLine( "After adding \"lazy\", the ArrayList now contains:" );
PrintValues( myAL );
// Add "!!!" at the end.
myAL.Insert( myAL.Count, "!!!" );
// Displays the ArrayList.
Console.WriteLine( "After adding \"!!!\", the ArrayList now contains:" );
PrintValues( myAL );
// Inserting an element beyond Count throws an exception.
try {
myAL.Insert( myAL.Count+1, "anystring" );
} catch ( Exception myException ) {
Console.WriteLine("Exception: " + myException.ToString());
}
}
public static void PrintValues( IEnumerable myList ) {
foreach ( Object obj in myList )
Console.Write( " {0}", obj );
Console.WriteLine();
}
}
/*
This code produces the following output.
The ArrayList initially contains the following:
The fox jumps over the dog
The Queue initially contains the following:
quick brown
After adding the Queue, the ArrayList now contains:
The quick brown fox jumps over the dog
After adding "lazy", the ArrayList now contains:
The quick brown fox jumps over the lazy dog
After adding "!!!", the ArrayList now contains:
The quick brown fox jumps over the lazy dog !!!
Exception: System.ArgumentOutOfRangeException: Insertion index was out of range. Must be non-negative and less than or equal to size.
Parameter name: index
at System.Collections.ArrayList.Insert(int index, Object value)
at SamplesArrayList.Main()
*/
Imports System.Collections
Public Class SamplesArrayList
Public Shared Sub Main()
' Creates and initializes a new ArrayList using Insert instead of Add.
Dim myAL As New ArrayList()
myAL.Insert(0, "The")
myAL.Insert(1, "fox")
myAL.Insert(2, "jumps")
myAL.Insert(3, "over")
myAL.Insert(4, "the")
myAL.Insert(5, "dog")
' Creates and initializes a new Queue.
Dim myQueue As New Queue()
myQueue.Enqueue("quick")
myQueue.Enqueue("brown")
' Displays the ArrayList and the Queue.
Console.WriteLine("The ArrayList initially contains the following:")
PrintValues(myAL)
Console.WriteLine("The Queue initially contains the following:")
PrintValues(myQueue)
' Copies the Queue elements to the ArrayList at index 1.
myAL.InsertRange(1, myQueue)
' Displays the ArrayList.
Console.WriteLine("After adding the Queue, the ArrayList now contains:")
PrintValues(myAL)
' Search for "dog" and add "lazy" before it.
myAL.Insert(myAL.IndexOf("dog"), "lazy")
' Displays the ArrayList.
Console.WriteLine("After adding ""lazy"", the ArrayList now contains:")
PrintValues(myAL)
' Add "!!!" at the end.
myAL.Insert(myAL.Count, "!!!")
' Displays the ArrayList.
Console.WriteLine("After adding ""!!!"", the ArrayList now contains:")
PrintValues(myAL)
' Inserting an element beyond Count throws an exception.
Try
myAL.Insert(myAL.Count + 1, "anystring")
Catch myException As Exception
Console.WriteLine("Exception: " + myException.ToString())
End Try
End Sub
Public Shared Sub PrintValues(myList As IEnumerable)
Dim obj As [Object]
For Each obj In myList
Console.Write(" {0}", obj)
Next obj
Console.WriteLine()
End Sub
End Class
' This code produces the following output.
'
' The ArrayList initially contains the following:
' The fox jumps over the dog
' The Queue initially contains the following:
' quick brown
' After adding the Queue, the ArrayList now contains:
' The quick brown fox jumps over the dog
' After adding "lazy", the ArrayList now contains:
' The quick brown fox jumps over the lazy dog
' After adding "!!!", the ArrayList now contains:
' The quick brown fox jumps over the lazy dog !!!
' Exception: System.ArgumentOutOfRangeException: Insertion index was out of range. Must be non-negative and less than or equal to size.
' Parameter name: index
' at System.Collections.ArrayList.Insert(Int32 index, Object value)
' at SamplesArrayList.Main()
Poznámky
ArrayList přijímá null
jako platnou hodnotu a umožňuje duplicitní prvky.
Pokud Count se již rovná Capacity, kapacita objektu ArrayList se zvýší automatickým opětovným přidělením interního pole a existující prvky se zkopírují do nového pole před přidáním nového prvku.
Pokud index
se hodnota rovná hodnotě Count, value
přidá se na konec .ArrayList
V kolekcích souvislých prvků, například seznamů, se prvky následující po bodu vložení při vložení nového prvku posouvají dolů. Je-li kolekce indexována, budou aktualizovány rovněž indexy přesunutých prvků. Toto chování se nevztahuje na kolekce, kde prvky jsou koncepčně seskupeny do sad, tj. například na tabulky hash.
Tato metoda je O(n)
operace, kde n
je Count.