ArrayList.ReadOnly 메서드

Source:

ArrayList.cs

Source:

ArrayList.cs

Source:

ArrayList.cs

public:
 static System::Collections::ArrayList ^ ReadOnly(System::Collections::ArrayList ^ list);

public static System.Collections.ArrayList ReadOnly (System.Collections.ArrayList list);

static member ReadOnly : System.Collections.ArrayList -> System.Collections.ArrayList

Public Shared Function ReadOnly (list As ArrayList) As ArrayList

매개 변수

반환

list 주변의 읽기 전용 ArrayList 래퍼입니다.

예외

예제

다음 코드 예제에서는 주위에 ArrayList 읽기 전용 래퍼를 만드는 방법과 가 읽기 전용인지 ArrayList 여부를 확인하는 방법을 보여줍니다.

#using <system.dll>

using namespace System;
using namespace System::Collections;
int main()
{
   
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "red" );
   myAL->Add( "orange" );
   myAL->Add( "yellow" );
   
   // Creates a read-only copy of the ArrayList.
   ArrayList^ myReadOnlyAL = ArrayList::ReadOnly( myAL );
   
   // Displays whether the ArrayList is read-only or writable.
   Console::WriteLine( "myAL is {0}.", myAL->IsReadOnly ? (String^)"read-only" : "writable" );
   Console::WriteLine( "myReadOnlyAL is {0}.", myReadOnlyAL->IsReadOnly ? (String^)"read-only" : "writable" );
   
   // Displays the contents of both collections.
   Console::WriteLine( "\nInitially," );
   Console::WriteLine( "The original ArrayList myAL contains:" );
   for ( int i(0); i < myAL->Count; ++i )
      Console::WriteLine(  "   {0}", static_cast<String^>(myAL[ i ]) );
   Console::WriteLine( "The read-only ArrayList myReadOnlyAL contains:" );
   for ( int i(0); i < myReadOnlyAL->Count; ++i )
      Console::WriteLine( "   {0}", static_cast<String^>(myReadOnlyAL[ i ]) );
   
   // Adding an element to a read-only ArrayList throws an exception.
   Console::WriteLine( "\nTrying to add a new element to the read-only ArrayList:" );
   try
   {
      myReadOnlyAL->Add( "green" );
   }
   catch ( Exception^ myException ) 
   {
      Console::WriteLine( String::Concat( "Exception: ", myException->ToString() ) );
   }

   
   // Adding an element to the original ArrayList affects the read-only ArrayList.
   myAL->Add( "blue" );
   
   // Displays the contents of both collections again.
   Console::WriteLine( "\nAfter adding a new element to the original ArrayList," );
   Console::WriteLine( "The original ArrayList myAL contains:" );
   for ( int i(0); i < myAL->Count; ++i )
      Console::WriteLine( "   {0}", static_cast<String^>(myAL[ i ]) );
   Console::WriteLine( "The read-only ArrayList myReadOnlyAL contains:" );
   for ( int i(0); i < myReadOnlyAL->Count; ++i )
      Console::WriteLine( "   {0}", static_cast<String^>(myReadOnlyAL[ i ]) );
}

/*
This code produces the following output.

myAL is writable.
myReadOnlyAL is read-only.

Initially,
The original ArrayList myAL contains:
   red
   orange
   yellow
The read-only ArrayList myReadOnlyAL contains:
   red
   orange
   yellow

Trying to add a new element to the read-only ArrayList:
Exception: System.NotSupportedException: Collection is read-only.
   at System.Collections.ReadOnlyArrayList.Add(Object obj)
   at SamplesArrayList.Main()

After adding a new element to the original ArrayList,
The original ArrayList myAL contains:
   red
   orange
   yellow
   blue
The read-only ArrayList myReadOnlyAL contains:
   red
   orange
   yellow
   blue

*/

 using System;
 using System.Collections;
 public class SamplesArrayList  {

    public static void Main()  {

       // Creates and initializes a new ArrayList.
       ArrayList myAL = new ArrayList();
       myAL.Add( "red" );
       myAL.Add( "orange" );
       myAL.Add( "yellow" );

       // Creates a read-only copy of the ArrayList.
       ArrayList myReadOnlyAL = ArrayList.ReadOnly( myAL );

       // Displays whether the ArrayList is read-only or writable.
       Console.WriteLine( "myAL is {0}.", myAL.IsReadOnly ? "read-only" : "writable" );
       Console.WriteLine( "myReadOnlyAL is {0}.", myReadOnlyAL.IsReadOnly ? "read-only" : "writable" );

       // Displays the contents of both collections.
       Console.WriteLine( "\nInitially," );
       Console.WriteLine( "The original ArrayList myAL contains:" );
       foreach ( string myStr in myAL )
          Console.WriteLine( "   {0}", myStr );
       Console.WriteLine( "The read-only ArrayList myReadOnlyAL contains:" );
       foreach ( string myStr in myReadOnlyAL )
          Console.WriteLine( "   {0}", myStr );

       // Adding an element to a read-only ArrayList throws an exception.
       Console.WriteLine( "\nTrying to add a new element to the read-only ArrayList:" );
       try  {
          myReadOnlyAL.Add("green");
       } catch ( Exception myException )  {
          Console.WriteLine("Exception: " + myException.ToString());
       }

       // Adding an element to the original ArrayList affects the read-only ArrayList.
       myAL.Add( "blue" );

       // Displays the contents of both collections again.
       Console.WriteLine( "\nAfter adding a new element to the original ArrayList," );
       Console.WriteLine( "The original ArrayList myAL contains:" );
       foreach ( string myStr in myAL )
          Console.WriteLine( "   {0}", myStr );
       Console.WriteLine( "The read-only ArrayList myReadOnlyAL contains:" );
       foreach ( string myStr in myReadOnlyAL )
          Console.WriteLine( "   {0}", myStr );
    }
 }


/*
This code produces the following output.

myAL is writable.
myReadOnlyAL is read-only.

Initially,
The original ArrayList myAL contains:
   red
   orange
   yellow
The read-only ArrayList myReadOnlyAL contains:
   red
   orange
   yellow

Trying to add a new element to the read-only ArrayList:
Exception: System.NotSupportedException: Collection is read-only.
   at System.Collections.ReadOnlyArrayList.Add(Object obj)
   at SamplesArrayList.Main()

After adding a new element to the original ArrayList,
The original ArrayList myAL contains:
   red
   orange
   yellow
   blue
The read-only ArrayList myReadOnlyAL contains:
   red
   orange
   yellow
   blue

*/

Imports System.Collections

Public Class SamplesArrayList

   Public Shared Sub Main()

      Dim myStr As [String]

      ' Creates and initializes a new ArrayList.
      Dim myAL As New ArrayList()
      myAL.Add("red")
      myAL.Add("orange")
      myAL.Add("yellow")

      ' Creates a read-only copy of the ArrayList.
      Dim myReadOnlyAL As ArrayList = ArrayList.ReadOnly(myAL)

      ' Displays whether the ArrayList is read-only or writable.
      If myAL.IsReadOnly Then
         Console.WriteLine("myAL is read-only.")
      Else
         Console.WriteLine("myAL is writable.")
      End If
      If myReadOnlyAL.IsReadOnly Then
         Console.WriteLine("myReadOnlyAL is read-only.")
      Else
         Console.WriteLine("myReadOnlyAL is writable.")
      End If

      ' Displays the contents of both collections.
      Console.WriteLine()
      Console.WriteLine("Initially,")
      Console.WriteLine("The original ArrayList myAL contains:")
      For Each myStr In  myAL
         Console.WriteLine("   {0}", myStr)
      Next myStr
      Console.WriteLine("The read-only ArrayList myReadOnlyAL contains:")
      For Each myStr In  myReadOnlyAL
         Console.WriteLine("   {0}", myStr)
      Next myStr 

      ' Adding an element to a read-only ArrayList throws an exception.
      Console.WriteLine()
      Console.WriteLine("Trying to add a new element to the read-only ArrayList:")
      Try
         myReadOnlyAL.Add("green")
      Catch myException As Exception
         Console.WriteLine(("Exception: " + myException.ToString()))
      End Try

      ' Adding an element to the original ArrayList affects the read-only ArrayList.
      myAL.Add("blue")

      ' Displays the contents of both collections again.
      Console.WriteLine()
      Console.WriteLine("After adding a new element to the original ArrayList,")
      Console.WriteLine("The original ArrayList myAL contains:")
      For Each myStr In  myAL
         Console.WriteLine("   {0}", myStr)
      Next myStr
      Console.WriteLine("The read-only ArrayList myReadOnlyAL contains:")
      For Each myStr In  myReadOnlyAL
         Console.WriteLine("   {0}", myStr)
      Next myStr 

   End Sub

End Class


'This code produces the following output.
'
'myAL is writable.
'myReadOnlyAL is read-only.
'
'Initially,
'The original ArrayList myAL contains:
'   red
'   orange
'   yellow
'The read-only ArrayList myReadOnlyAL contains:
'   red
'   orange
'   yellow
'
'Trying to add a new element to the read-only ArrayList:
'Exception: System.NotSupportedException: Collection is read-only.
'   at System.Collections.ReadOnlyArrayList.Add(Object obj)
'   at SamplesArrayList.Main()
'
'After adding a new element to the original ArrayList,
'The original ArrayList myAL contains:
'   red
'   orange
'   yellow
'   blue
'The read-only ArrayList myReadOnlyAL contains:
'   red
'   orange
'   yellow
'   blue

설명

에 대한 수정을 방지하려면 이 래퍼를 list통해서만 노출 list 합니다.

읽기 전용인 컬렉션은 단순히 컬렉션을 수정할 수 없는 래퍼가 있는 컬렉션입니다. 기본 컬렉션이 변경 되 면 읽기 전용 컬렉션을 해당 변경 내용을 반영 합니다.

이 메서드는 작업입니다 O(1) .

추가 정보

• IsReadOnly

Source:

ArrayList.cs

Source:

ArrayList.cs

Source:

ArrayList.cs

public:
 static System::Collections::IList ^ ReadOnly(System::Collections::IList ^ list);

public static System.Collections.IList ReadOnly (System.Collections.IList list);

static member ReadOnly : System.Collections.IList -> System.Collections.IList

Public Shared Function ReadOnly (list As IList) As IList

매개 변수

반환

list 주변의 읽기 전용 IList 래퍼입니다.

예외

설명

에 대한 수정을 방지하려면 이 래퍼를 list통해서만 노출 list 합니다.

읽기 전용인 컬렉션은 단순히 컬렉션을 수정할 수 없는 래퍼가 있는 컬렉션입니다. 기본 컬렉션이 변경 되 면 읽기 전용 컬렉션을 해당 변경 내용을 반영 합니다.

이 메서드는 작업입니다 O(1) .

추가 정보

• IsReadOnly