ArrayList.IsFixedSize 属性

  • 项目

获取一个值，该值指示 ArrayList 是否具有固定大小。

**命名空间:**System.Collections
**程序集:**mscorlib（在 mscorlib.dll 中）

语法

声明
Public Overridable ReadOnly Property IsFixedSize As Boolean
用法
Dim instance As ArrayList
Dim value As Boolean

value = instance.IsFixedSize

public virtual bool IsFixedSize { get; }

public:
virtual property bool IsFixedSize {
    bool get ();
}

/** @property */
public boolean get_IsFixedSize ()

public function get IsFixedSize () : boolean

属性值

如果 ArrayList 具有固定大小，则为 true；否则为 false。默认为 false。

备注

大小固定的集合在创建之后不允许添加或移除元素，但允许修改现有元素。

固定大小的集合只是一个具有用于防止添加和移除元素的包装的集合；因此，如果更改基础集合（包括添加和移除元素），则固定大小的集合将反映那些更改。

检索此属性的值的运算复杂度为 O(1)。

示例

下面的代码示例演示如何在 ArrayList 周围创建一个大小固定的包装。

Imports System
Imports System.Collections
Imports Microsoft.VisualBasic

Public Class SamplesArrayList    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new ArrayList.
        Dim myAL As New ArrayList()
        myAL.Add("The")
        myAL.Add("quick")
        myAL.Add("brown")
        myAL.Add("fox")
        myAL.Add("jumped")
        myAL.Add("over")
        myAL.Add("the")
        myAL.Add("lazy")
        myAL.Add("dog")
        
        ' Create a fixed-size wrapper around the ArrayList.
        Dim myFixedSizeAL As ArrayList = ArrayList.FixedSize(myAL)
        
        ' Display whether the ArrayLists have a fixed size or not.
        Dim msg As String
        If myAL.IsFixedSize Then
            msg = "has a fixed size"
        Else
            msg = "does not have a fixed size"
        End If
        Console.WriteLine("myAL {0}.", msg)
        If myFixedSizeAL.IsFixedSize Then
            msg = "has a fixed size"
        Else
            msg = "does not have a fixed size"
        End If
        Console.WriteLine("myFixedSizeAL {0}.", msg)
        Console.WriteLine()
        
        ' Display both ArrayLists.
        Console.WriteLine("Initially,")
        Console.Write("Standard  :")
        PrintValues(myAL, " "c)
        Console.Write("Fixed size:")
        PrintValues(myFixedSizeAL, " "c)
        
        ' Sort is allowed in the fixed-size ArrayList.
        myFixedSizeAL.Sort()
        
        ' Display both ArrayLists.
        Console.WriteLine("After Sort,")
        Console.Write("Standard  :")
        PrintValues(myAL, " "c)
        Console.Write("Fixed size:")
        PrintValues(myFixedSizeAL, " "c)
        
        ' Reverse is allowed in the fixed-size ArrayList.
        myFixedSizeAL.Reverse()
        
        ' Display both ArrayLists.
        Console.WriteLine("After Reverse,")
        Console.Write("Standard  :")
        PrintValues(myAL, " "c)
        Console.Write("Fixed size:")
        PrintValues(myFixedSizeAL, " "c)
        
        ' Add an element to the standard ArrayList.
        myAL.Add("AddMe")
        
        ' Display both ArrayLists.
        Console.WriteLine("After adding to the standard ArrayList,")
        Console.Write("Standard  :")
        PrintValues(myAL, " "c)
        Console.Write("Fixed size:")
        PrintValues(myFixedSizeAL, " "c)
        Console.WriteLine()
        
        ' Adding or inserting elements to the fixed-size ArrayList throws an exception.
        Try
            myFixedSizeAL.Add("AddMe2")
        Catch myException As Exception
            Console.WriteLine("Exception: " + myException.ToString())
        End Try
        Try
            myFixedSizeAL.Insert(3, "InsertMe")
        Catch myException As Exception
            Console.WriteLine("Exception: " + myException.ToString())
        End Try
    End Sub 'Main

    Public Shared Sub PrintValues(myList As IEnumerable, mySeparator As Char)
        Dim obj As [Object]
        For Each obj In  myList
            Console.Write("{0}{1}", mySeparator, obj)
        Next obj
        Console.WriteLine()
    End Sub 'PrintValues

End Class


' This code produces the following output.
' 
' myAL does not have a fixed size.
' myFixedSizeAL has a fixed size.
' 
' Initially,
' Standard  : The quick brown fox jumped over the lazy dog
' Fixed size: The quick brown fox jumped over the lazy dog
' After Sort,
' Standard  : brown dog fox jumped lazy over quick the The
' Fixed size: brown dog fox jumped lazy over quick the The
' After Reverse,
' Standard  : The the quick over lazy jumped fox dog brown
' Fixed size: The the quick over lazy jumped fox dog brown
' After adding to the standard ArrayList,
' Standard  : The the quick over lazy jumped fox dog brown AddMe
' Fixed size: The the quick over lazy jumped fox dog brown AddMe
' 
' Exception: System.NotSupportedException: Collection was of a fixed size.
'    at System.Collections.FixedSizeArrayList.Add(Object obj)
'    at SamplesArrayList.Main()
' Exception: System.NotSupportedException: Collection was of a fixed size.
'    at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
'    at SamplesArrayList.Main()

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

   public static void Main()  {

      // Creates and initializes a new ArrayList.
      ArrayList myAL = new ArrayList();
      myAL.Add( "The" );
      myAL.Add( "quick" );
      myAL.Add( "brown" );
      myAL.Add( "fox" );
      myAL.Add( "jumped" );
      myAL.Add( "over" );
      myAL.Add( "the" );
      myAL.Add( "lazy" );
      myAL.Add( "dog" );

      // Create a fixed-size wrapper around the ArrayList.
      ArrayList myFixedSizeAL = ArrayList.FixedSize( myAL );

      // Display whether the ArrayLists have a fixed size or not.
      Console.WriteLine( "myAL {0}.", myAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
      Console.WriteLine( "myFixedSizeAL {0}.", myFixedSizeAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
      Console.WriteLine();

      // Display both ArrayLists.
      Console.WriteLine( "Initially," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Sort is allowed in the fixed-size ArrayList.
      myFixedSizeAL.Sort();

      // Display both ArrayLists.
      Console.WriteLine( "After Sort," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Reverse is allowed in the fixed-size ArrayList.
      myFixedSizeAL.Reverse();

      // Display both ArrayLists.
      Console.WriteLine( "After Reverse," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );

      // Add an element to the standard ArrayList.
      myAL.Add( "AddMe" );

      // Display both ArrayLists.
      Console.WriteLine( "After adding to the standard ArrayList," );
      Console.Write( "Standard  :" );
      PrintValues( myAL, ' ' );
      Console.Write( "Fixed size:" );
      PrintValues( myFixedSizeAL, ' ' );
      Console.WriteLine();

      // Adding or inserting elements to the fixed-size ArrayList throws an exception.
      try  {
         myFixedSizeAL.Add( "AddMe2" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
      try  {
         myFixedSizeAL.Insert( 3, "InsertMe" );
      } catch ( Exception myException )  {
         Console.WriteLine("Exception: " + myException.ToString());
      }
   }

   public static void PrintValues( IEnumerable myList, char mySeparator )  {
      foreach ( Object obj in myList )
         Console.Write( "{0}{1}", mySeparator, obj );
      Console.WriteLine();
   }

}
/*
This code produces the following output.

myAL does not have a fixed size.
myFixedSizeAL has a fixed size.

Initially,
Standard  : The quick brown fox jumped over the lazy dog
Fixed size: The quick brown fox jumped over the lazy dog
After Sort,
Standard  : brown dog fox jumped lazy over quick the The
Fixed size: brown dog fox jumped lazy over quick the The
After Reverse,
Standard  : The the quick over lazy jumped fox dog brown
Fixed size: The the quick over lazy jumped fox dog brown
After adding to the standard ArrayList,
Standard  : The the quick over lazy jumped fox dog brown AddMe
Fixed size: The the quick over lazy jumped fox dog brown AddMe

Exception: System.NotSupportedException: Collection was of a fixed size.
   at System.Collections.FixedSizeArrayList.Add(Object obj)
   at SamplesArrayList.Main()
Exception: System.NotSupportedException: Collection was of a fixed size.
   at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
   at SamplesArrayList.Main()

*/ 

using namespace System;
using namespace System::Collections;
void PrintValues( IEnumerable^ myList, char mySeparator );
int main()
{
   
   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   myAL->Add( "jumped" );
   myAL->Add( "over" );
   myAL->Add( "the" );
   myAL->Add( "lazy" );
   myAL->Add( "dog" );
   
   // Create a fixed-size wrapper around the ArrayList.
   ArrayList^ myFixedSizeAL = ArrayList::FixedSize( myAL );
   
   // Display whether the ArrayLists have a fixed size or not.
   Console::WriteLine( "myAL {0}.", myAL->IsFixedSize ? (String^)"has a fixed size" : "does not have a fixed size" );
   Console::WriteLine( "myFixedSizeAL {0}.", myFixedSizeAL->IsFixedSize ? (String^)"has a fixed size" : "does not have a fixed size" );
   Console::WriteLine();
   
   // Display both ArrayLists.
   Console::WriteLine( "Initially," );
   Console::Write( "Standard  :" );
   PrintValues( myAL, ' ' );
   Console::Write( "Fixed size:" );
   PrintValues( myFixedSizeAL, ' ' );
   
   // Sort is allowed in the fixed-size ArrayList.
   myFixedSizeAL->Sort();
   
   // Display both ArrayLists.
   Console::WriteLine( "After Sort," );
   Console::Write( "Standard  :" );
   PrintValues( myAL, ' ' );
   Console::Write( "Fixed size:" );
   PrintValues( myFixedSizeAL, ' ' );
   
   // Reverse is allowed in the fixed-size ArrayList.
   myFixedSizeAL->Reverse();
   
   // Display both ArrayLists.
   Console::WriteLine( "After Reverse," );
   Console::Write( "Standard  :" );
   PrintValues( myAL, ' ' );
   Console::Write( "Fixed size:" );
   PrintValues( myFixedSizeAL, ' ' );
   
   // Add an element to the standard ArrayList.
   myAL->Add( "AddMe" );
   
   // Display both ArrayLists.
   Console::WriteLine( "After adding to the standard ArrayList," );
   Console::Write( "Standard  :" );
   PrintValues( myAL, ' ' );
   Console::Write( "Fixed size:" );
   PrintValues( myFixedSizeAL, ' ' );
   Console::WriteLine();
   
   // Adding or inserting elements to the fixed-size ArrayList throws an exception.
   try
   {
      myFixedSizeAL->Add( "AddMe2" );
   }
   catch ( Exception^ myException ) 
   {
      Console::WriteLine( "Exception: {0}", myException );
   }

   try
   {
      myFixedSizeAL->Insert( 3, "InsertMe" );
   }
   catch ( Exception^ myException ) 
   {
      Console::WriteLine( "Exception: {0}", myException );
   }

}

void PrintValues( IEnumerable^ myList, char mySeparator )
{
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::Write( "{0}{1}", mySeparator, obj );
   }

   Console::WriteLine();
}

/*
 This code produces the following output.
 
 myAL does not have a fixed size.
 myFixedSizeAL has a fixed size.

 Initially,
 Standard  : The quick brown fox jumped over the lazy dog
 Fixed size: The quick brown fox jumped over the lazy dog
 After Sort,
 Standard  : brown dog fox jumped lazy over quick the The
 Fixed size: brown dog fox jumped lazy over quick the The
 After Reverse,
 Standard  : The the quick over lazy jumped fox dog brown
 Fixed size: The the quick over lazy jumped fox dog brown
 After adding to the standard ArrayList,
 Standard  : The the quick over lazy jumped fox dog brown AddMe
 Fixed size: The the quick over lazy jumped fox dog brown AddMe

 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Add(Object obj)
    at SamplesArrayList.Main()
 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
    at SamplesArrayList.Main()

 */

import System.*;
import System.Collections.*;

public class SamplesArrayList
{
    public static void main(String[] args)
    {
        // Creates and initializes a new ArrayList.
        ArrayList myAL = new ArrayList();

        myAL.Add("The");
        myAL.Add("quick");
        myAL.Add("brown");
        myAL.Add("fox");
        myAL.Add("jumped");
        myAL.Add("over");
        myAL.Add("the");
        myAL.Add("lazy");
        myAL.Add("dog");

        // Create a fixed-size wrapper around the ArrayList.
        ArrayList myFixedSizeAL = ArrayList.FixedSize(myAL);

        // Display whether the ArrayLists have a fixed size or not.
        Console.WriteLine("myAL {0}.", myAL.get_IsFixedSize()
            ? "has a fixed size" : "does not have a fixed size");
        Console.WriteLine("myFixedSizeAL {0}.", myFixedSizeAL.get_IsFixedSize()
            ? "has a fixed size" : "does not have a fixed size");
        Console.WriteLine();

        // Display both ArrayLists.
        Console.WriteLine("Initially,");
        Console.Write("Standard  :");
        PrintValues(myAL, ' ');
        Console.Write("Fixed size:");
        PrintValues(myFixedSizeAL, ' ');

        // Sort is allowed in the fixed-size ArrayList.
        myFixedSizeAL.Sort();

        // Display both ArrayLists.
        Console.WriteLine("After Sort,");
        Console.Write("Standard  :");
        PrintValues(myAL, ' ');
        Console.Write("Fixed size:");
        PrintValues(myFixedSizeAL, ' ');

        // Reverse is allowed in the fixed-size ArrayList.
        myFixedSizeAL.Reverse();

        // Display both ArrayLists.
        Console.WriteLine("After Reverse,");
        Console.Write("Standard  :");
        PrintValues(myAL, ' ');
        Console.Write("Fixed size:");
        PrintValues(myFixedSizeAL, ' ');

        // Add an element to the standard ArrayList.
        myAL.Add("AddMe");

        // Display both ArrayLists.
        Console.WriteLine("After adding to the standard ArrayList,");
        Console.Write("Standard  :");
        PrintValues(myAL, ' ');
        Console.Write("Fixed size:");
        PrintValues(myFixedSizeAL, ' ');
        Console.WriteLine();

        // Adding or inserting elements to the fixed-size ArrayList throws an 
        // exception.
        try {
            myFixedSizeAL.Add("AddMe2");
        }
        catch (System.Exception myException) {
            Console.WriteLine("Exception: " + myException.ToString());
        }
        try {
            myFixedSizeAL.Insert(3, "InsertMe");
        }
        catch (System.Exception myException) {
            Console.WriteLine("Exception: " + myException.ToString());
        }
    } //main

    public static void PrintValues(IEnumerable myList, char mySeparator)
    {
        IEnumerator objMyEnum = myList.GetEnumerator();
        while (objMyEnum.MoveNext()) {
            Object obj = objMyEnum.get_Current();
            Console.Write("{0}{1}", new Character(mySeparator), obj);
        }
        Console.WriteLine();
    } //PrintValues
} //SamplesArrayList 
/*
 This code produces the following output.
 
 myAL does not have a fixed size.
 myFixedSizeAL has a fixed size.

 Initially,
 Standard  : The quick brown fox jumped over the lazy dog
 Fixed size: The quick brown fox jumped over the lazy dog
 After Sort,
 Standard  : brown dog fox jumped lazy over quick the The
 Fixed size: brown dog fox jumped lazy over quick the The
 After Reverse,
 Standard  : The the quick over lazy jumped fox dog brown
 Fixed size: The the quick over lazy jumped fox dog brown
 After adding to the standard ArrayList,
 Standard  : The the quick over lazy jumped fox dog brown AddMe
 Fixed size: The the quick over lazy jumped fox dog brown AddMe

 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Add(Object obj)
    at SamplesArrayList.main(String[] args)
 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
    at SamplesArrayList.main(String[] args)

 */

import System;
import System.Collections;


// Creates and initializes a new ArrayList.
var myAL : ArrayList = new ArrayList();
myAL.Add( "The" );
myAL.Add( "quick" );
myAL.Add( "brown" );
myAL.Add( "fox" );
myAL.Add( "jumped" );
myAL.Add( "over" );
myAL.Add( "the" );
myAL.Add( "lazy" );
myAL.Add( "dog" );

// Create a fixed-size wrapper around the ArrayList.
var myFixedSizeAL : ArrayList = ArrayList.FixedSize( myAL );

// Display whether the ArrayLists have a fixed size or not.
Console.WriteLine( "myAL {0}.", myAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
Console.WriteLine( "myFixedSizeAL {0}.", myFixedSizeAL.IsFixedSize ? "has a fixed size" : "does not have a fixed size" );
Console.WriteLine();

// Display both ArrayLists.
Console.WriteLine( "Initially," );
Console.Write( "Standard  :" );
PrintValues( myAL, ' ' );
Console.Write( "Fixed size:" );
PrintValues( myFixedSizeAL, ' ' );

// Sort is allowed in the fixed-size ArrayList.
myFixedSizeAL.Sort();

// Display both ArrayLists.
Console.WriteLine( "After Sort," );
Console.Write( "Standard  :" );
PrintValues( myAL, ' ' );
Console.Write( "Fixed size:" );
PrintValues( myFixedSizeAL, ' ' );

// Reverse is allowed in the fixed-size ArrayList.
myFixedSizeAL.Reverse();

// Display both ArrayLists.
Console.WriteLine( "After Reverse," );
Console.Write( "Standard  :" );
PrintValues( myAL, ' ' );
Console.Write( "Fixed size:" );
PrintValues( myFixedSizeAL, ' ' );

// Add an element to the standard ArrayList.
myAL.Add( "AddMe" );

// Display both ArrayLists.
Console.WriteLine( "After adding to the standard ArrayList," );
Console.Write( "Standard  :" );
PrintValues( myAL, ' ' );
Console.Write( "Fixed size:" );
PrintValues( myFixedSizeAL, ' ' );
Console.WriteLine();

// Adding or inserting elements to the fixed-size ArrayList throws an exception.
try  {
  myFixedSizeAL.Add( "AddMe2" );
} catch ( myException : Exception  )  {
  Console.WriteLine("Exception: " + myException.ToString());
}
try  {
  myFixedSizeAL.Insert( 3, "InsertMe" );
} catch ( myException : Exception )  {
  Console.WriteLine("Exception: " + myException.ToString());
}

 
function PrintValues( myList : IEnumerable, mySeparator : char )  {
   var myEnumerator : System.Collections.IEnumerator  = myList.GetEnumerator();
   while ( myEnumerator.MoveNext() )
      Console.Write( "{0}{1}", mySeparator, myEnumerator.Current );
   Console.WriteLine();
}
 /*
 This code produces the following output.
 
 myAL does not have a fixed size.
 myFixedSizeAL has a fixed size.
 
 Initially,
 Standard  : The quick brown fox jumped over the lazy dog
 Fixed size: The quick brown fox jumped over the lazy dog
 After Sort,
 Standard  : brown dog fox jumped lazy over quick the The
 Fixed size: brown dog fox jumped lazy over quick the The
 After Reverse,
 Standard  : The the quick over lazy jumped fox dog brown
 Fixed size: The the quick over lazy jumped fox dog brown
 After adding to the standard ArrayList,
 Standard  : The the quick over lazy jumped fox dog brown AddMe
 Fixed size: The the quick over lazy jumped fox dog brown AddMe
 
 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Add(Object obj)
    at JScript 0.Global Code()
 Exception: System.NotSupportedException: Collection was of a fixed size.
    at System.Collections.FixedSizeArrayList.Insert(Int32 index, Object obj)
    at JScript 0.Global Code()
 */

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

.NET Compact Framework

受以下版本支持：2.0、1.0

请参见

参考

ArrayList 类
ArrayList 成员
System.Collections 命名空间