NameObjectCollectionBase 类

定义

命名空间:

System.Collections.Specialized

程序集:

System.Collections.Specialized.dll

Source:

NameObjectCollectionBase.cs

为关联的 abstract 键和 String 值的集合（可通过键或索引来访问它）提供 Object 基类。

public ref class NameObjectCollectionBase abstract : System::Collections::ICollection, System::Runtime::Serialization::IDeserializationCallback, System::Runtime::Serialization::ISerializable

public abstract class NameObjectCollectionBase : System.Collections.ICollection, System.Runtime.Serialization.IDeserializationCallback, System.Runtime.Serialization.ISerializable

type NameObjectCollectionBase = class
    interface ICollection
    interface IEnumerable
    interface IDeserializationCallback
    interface ISerializable

Public MustInherit Class NameObjectCollectionBase
Implements ICollection, IDeserializationCallback, ISerializable

继承

Object

NameObjectCollectionBase

派生

System.Collections.Specialized.NameValueCollection

System.Configuration.ConfigurationSectionCollection

System.Configuration.ConfigurationSectionGroupCollection

System.Configuration.PropertyInformationCollection

System.Management.ManagementNamedValueCollection

System.Web.Configuration.VirtualDirectoryMappingCollection

System.Web.HttpApplicationState

System.Web.HttpApplicationStateBase

System.Web.HttpCookieCollection

System.Web.HttpFileCollection

System.Web.HttpFileCollectionBase

System.Web.HttpModuleCollection

System.Web.SessionState.SessionStateItemCollection

实现

ICollection IEnumerable IDeserializationCallback ISerializable

示例

下面的代码示例演示如何实现和使用 NameObjectCollectionBase 类。

#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;

public ref class MyCollection : public NameObjectCollectionBase  {

private:
   DictionaryEntry^ _de;

   // Creates an empty collection.
public:
   MyCollection()  {
      _de = gcnew DictionaryEntry();
   }

   // Adds elements from an IDictionary into the new collection.
   MyCollection( IDictionary^ d, Boolean bReadOnly )  {

      _de = gcnew DictionaryEntry();

      for each ( DictionaryEntry^ de in d )  {
         this->BaseAdd( (String^) de->Key, de->Value );
      }
      this->IsReadOnly = bReadOnly;
   }

   // Gets a key-and-value pair (DictionaryEntry) using an index.
   property DictionaryEntry^ default[ int ]  {
      DictionaryEntry^ get(int index)  {
         _de->Key = this->BaseGetKey(index);
         _de->Value = this->BaseGet(index);
         return( _de );
      }
   }

   // Gets or sets the value associated with the specified key.
   property Object^ default[ String^ ]  {
      Object^ get(String^ key)  {
         return( this->BaseGet( key ) );
      }
      void set( String^ key, Object^ value )  {
         this->BaseSet( key, value );
      }
   }

   // Gets a String array that contains all the keys in the collection.
   property array<String^>^ AllKeys  {
      array<String^>^ get()  {
         return( (array<String^>^)this->BaseGetAllKeys() );
      }
   }

   // Gets an Object array that contains all the values in the collection.
   property Array^ AllValues  {
      Array^ get()  {
         return( this->BaseGetAllValues() );
      }
   }

   // Gets a String array that contains all the values in the collection.
   property array<String^>^ AllStringValues  {
      array<String^>^ get()  {
         return( (array<String^>^) this->BaseGetAllValues(  String ::typeid ));
      }
   }

   // Gets a value indicating if the collection contains keys that are not null.
   property Boolean HasKeys  {
      Boolean get()  {
         return( this->BaseHasKeys() );
      }
   }

   // Adds an entry to the collection.
   void Add( String^ key, Object^ value )  {
      this->BaseAdd( key, value );
   }

   // Removes an entry with the specified key from the collection.
   void Remove( String^ key )  {
      this->BaseRemove( key );
   }

   // Removes an entry in the specified index from the collection.
   void Remove( int index )  {
      this->BaseRemoveAt( index );
   }

   // Clears all the elements in the collection.
   void Clear()  {
      this->BaseClear();
   }
};

public ref class SamplesNameObjectCollectionBase  {

public:
   static void Main()  {
      // Creates and initializes a new MyCollection that is read-only.
      IDictionary^ d = gcnew ListDictionary();
      d->Add( "red", "apple" );
      d->Add( "yellow", "banana" );
      d->Add( "green", "pear" );
      MyCollection^ myROCol = gcnew MyCollection( d, true );

      // Tries to add a new item.
      try  {
         myROCol->Add( "blue", "sky" );
      }
      catch ( NotSupportedException^ e )  {
         Console::WriteLine( e->ToString() );
      }

      // Displays the keys and values of the MyCollection.
      Console::WriteLine( "Read-Only Collection:" );
      PrintKeysAndValues( myROCol );

      // Creates and initializes an empty MyCollection that is writable.
      MyCollection^ myRWCol = gcnew MyCollection();

      // Adds new items to the collection.
      myRWCol->Add( "purple", "grape" );
      myRWCol->Add( "orange", "tangerine" );
      myRWCol->Add( "black", "berries" );
      Console::WriteLine( "Writable Collection (after adding values):" );
      PrintKeysAndValues( myRWCol );

      // Changes the value of one element.
      myRWCol["orange"] = "grapefruit";
      Console::WriteLine( "Writable Collection (after changing one value):" );
      PrintKeysAndValues( myRWCol );

      // Removes one item from the collection.
      myRWCol->Remove( "black" );
      Console::WriteLine( "Writable Collection (after removing one value):" );
      PrintKeysAndValues( myRWCol );

      // Removes all elements from the collection.
      myRWCol->Clear();
      Console::WriteLine( "Writable Collection (after clearing the collection):" );
      PrintKeysAndValues( myRWCol );
   }

   // Prints the indexes, keys, and values.
   static void PrintKeysAndValues( MyCollection^ myCol )  {
      for ( int i = 0; i < myCol->Count; i++ )  {
         Console::WriteLine( "[{0}] : {1}, {2}", i, myCol[i]->Key, myCol[i]->Value );
      }
   }

   // Prints the keys and values using AllKeys.
   static void PrintKeysAndValues2( MyCollection^ myCol )  {
      for each ( String^ s in myCol->AllKeys )  {
         Console::WriteLine( "{0}, {1}", s, myCol[s] );
      }
   }
};

int main()
{
    SamplesNameObjectCollectionBase::Main();
}

/*
This code produces the following output.

System.NotSupportedException: Collection is read-only.
   at System.Collections.Specialized.NameObjectCollectionBase.BaseAdd(String name, Object value)
   at SamplesNameObjectCollectionBase.Main()
Read-Only Collection:
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
Writable Collection (after adding values):
[0] : purple, grape
[1] : orange, tangerine
[2] : black, berries
Writable Collection (after changing one value):
[0] : purple, grape
[1] : orange, grapefruit
[2] : black, berries
Writable Collection (after removing one value):
[0] : purple, grape
[1] : orange, grapefruit
Writable Collection (after clearing the collection):

*/

using System;
using System.Collections;
using System.Collections.Specialized;

public class MyCollection : NameObjectCollectionBase
{
   // Creates an empty collection.
   public MyCollection()  {
   }

   // Adds elements from an IDictionary into the new collection.
   public MyCollection( IDictionary d, Boolean bReadOnly )  {
      foreach ( DictionaryEntry de in d )  {
         this.BaseAdd( (String) de.Key, de.Value );
      }
      this.IsReadOnly = bReadOnly;
   }

   // Gets a key-and-value pair (DictionaryEntry) using an index.
   public DictionaryEntry this[ int index ]  {
      get  {
          return ( new DictionaryEntry(
              this.BaseGetKey(index), this.BaseGet(index) ) );
      }
   }

   // Gets or sets the value associated with the specified key.
   public Object this[ String key ]  {
      get  {
         return( this.BaseGet( key ) );
      }
      set  {
         this.BaseSet( key, value );
      }
   }

   // Gets a String array that contains all the keys in the collection.
   public String[] AllKeys  {
      get  {
         return( this.BaseGetAllKeys() );
      }
   }

   // Gets an Object array that contains all the values in the collection.
   public Array AllValues  {
      get  {
         return( this.BaseGetAllValues() );
      }
   }

   // Gets a String array that contains all the values in the collection.
   public String[] AllStringValues  {
      get  {
         return( (String[]) this.BaseGetAllValues( typeof( string ) ));
      }
   }

   // Gets a value indicating if the collection contains keys that are not null.
   public Boolean HasKeys  {
      get  {
         return( this.BaseHasKeys() );
      }
   }

   // Adds an entry to the collection.
   public void Add( String key, Object value )  {
      this.BaseAdd( key, value );
   }

   // Removes an entry with the specified key from the collection.
   public void Remove( String key )  {
      this.BaseRemove( key );
   }

   // Removes an entry in the specified index from the collection.
   public void Remove( int index )  {
      this.BaseRemoveAt( index );
   }

   // Clears all the elements in the collection.
   public void Clear()  {
      this.BaseClear();
   }
}

public class SamplesNameObjectCollectionBase  {

   public static void Main()  {

      // Creates and initializes a new MyCollection that is read-only.
      IDictionary d = new ListDictionary();
      d.Add( "red", "apple" );
      d.Add( "yellow", "banana" );
      d.Add( "green", "pear" );
      MyCollection myROCol = new MyCollection( d, true );

      // Tries to add a new item.
      try  {
         myROCol.Add( "blue", "sky" );
      }
      catch ( NotSupportedException e )  {
         Console.WriteLine( e.ToString() );
      }

      // Displays the keys and values of the MyCollection.
      Console.WriteLine( "Read-Only Collection:" );
      PrintKeysAndValues( myROCol );

      // Creates and initializes an empty MyCollection that is writable.
      MyCollection myRWCol = new MyCollection();

      // Adds new items to the collection.
      myRWCol.Add( "purple", "grape" );
      myRWCol.Add( "orange", "tangerine" );
      myRWCol.Add( "black", "berries" );
      Console.WriteLine( "Writable Collection (after adding values):" );
      PrintKeysAndValues( myRWCol );

      // Changes the value of one element.
      myRWCol["orange"] = "grapefruit";
      Console.WriteLine( "Writable Collection (after changing one value):" );
      PrintKeysAndValues( myRWCol );

      // Removes one item from the collection.
      myRWCol.Remove( "black" );
      Console.WriteLine( "Writable Collection (after removing one value):" );
      PrintKeysAndValues( myRWCol );

      // Removes all elements from the collection.
      myRWCol.Clear();
      Console.WriteLine( "Writable Collection (after clearing the collection):" );
      PrintKeysAndValues( myRWCol );
   }

   // Prints the indexes, keys, and values.
   public static void PrintKeysAndValues( MyCollection myCol )  {
      for ( int i = 0; i < myCol.Count; i++ )  {
         Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value );
      }
   }

   // Prints the keys and values using AllKeys.
   public static void PrintKeysAndValues2( MyCollection myCol )  {
      foreach ( String s in myCol.AllKeys )  {
         Console.WriteLine( "{0}, {1}", s, myCol[s] );
      }
   }
}


/*
This code produces the following output.

System.NotSupportedException: Collection is read-only.
   at System.Collections.Specialized.NameObjectCollectionBase.BaseAdd(String name, Object value)
   at SamplesNameObjectCollectionBase.Main()
Read-Only Collection:
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
Writable Collection (after adding values):
[0] : purple, grape
[1] : orange, tangerine
[2] : black, berries
Writable Collection (after changing one value):
[0] : purple, grape
[1] : orange, grapefruit
[2] : black, berries
Writable Collection (after removing one value):
[0] : purple, grape
[1] : orange, grapefruit
Writable Collection (after clearing the collection):

*/

Imports System.Collections
Imports System.Collections.Specialized

Public Class MyCollection
   Inherits NameObjectCollectionBase

   ' Creates an empty collection.
   Public Sub New()
   End Sub

   ' Adds elements from an IDictionary into the new collection.
   Public Sub New(d As IDictionary, bReadOnly As Boolean)
      Dim de As DictionaryEntry
      For Each de In  d
         Me.BaseAdd(CType(de.Key, String), de.Value)
      Next de
      Me.IsReadOnly = bReadOnly
   End Sub

   ' Gets a key-and-value pair (DictionaryEntry) using an index.
   Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
      Get
            return new DictionaryEntry( _
                me.BaseGetKey(index), me.BaseGet(index) )
      End Get
   End Property

   ' Gets or sets the value associated with the specified key.
   Default Public Property Item(key As String) As Object
      Get
         Return Me.BaseGet(key)
      End Get
      Set
         Me.BaseSet(key, value)
      End Set
   End Property

   ' Gets a String array that contains all the keys in the collection.
   Public ReadOnly Property AllKeys() As String()
      Get
         Return Me.BaseGetAllKeys()
      End Get
   End Property

   ' Gets an Object array that contains all the values in the collection.
   Public ReadOnly Property AllValues() As Array
      Get
         Return Me.BaseGetAllValues()
      End Get
   End Property

   ' Gets a String array that contains all the values in the collection.
   Public ReadOnly Property AllStringValues() As String()
      Get
         Return CType(Me.BaseGetAllValues(GetType(String)), String())
      End Get
   End Property

   ' Gets a value indicating if the collection contains keys that are not null.
   Public ReadOnly Property HasKeys() As Boolean
      Get
         Return Me.BaseHasKeys()
      End Get
   End Property

   ' Adds an entry to the collection.
   Public Sub Add(key As String, value As Object)
      Me.BaseAdd(key, value)
   End Sub

   ' Removes an entry with the specified key from the collection.
   Overloads Public Sub Remove(key As String)
      Me.BaseRemove(key)
   End Sub

   ' Removes an entry in the specified index from the collection.
   Overloads Public Sub Remove(index As Integer)
      Me.BaseRemoveAt(index)
   End Sub

   ' Clears all the elements in the collection.
   Public Sub Clear()
      Me.BaseClear()
   End Sub

End Class


Public Class SamplesNameObjectCollectionBase   

   Public Shared Sub Main()

      ' Creates and initializes a new MyCollection that is read-only.
      Dim d As New ListDictionary()
      d.Add("red", "apple")
      d.Add("yellow", "banana")
      d.Add("green", "pear")
      Dim myROCol As New MyCollection(d, True)

      ' Tries to add a new item.
      Try
         myROCol.Add("blue", "sky")
      Catch e As NotSupportedException
         Console.WriteLine(e.ToString())
      End Try

      ' Displays the keys and values of the MyCollection.
      Console.WriteLine("Read-Only Collection:")
      PrintKeysAndValues(myROCol)

      ' Creates and initializes an empty MyCollection that is writable.
      Dim myRWCol As New MyCollection()

      ' Adds new items to the collection.
      myRWCol.Add("purple", "grape")
      myRWCol.Add("orange", "tangerine")
      myRWCol.Add("black", "berries")
      Console.WriteLine("Writable Collection (after adding values):")
      PrintKeysAndValues(myRWCol)

      ' Changes the value of one element.
      myRWCol("orange") = "grapefruit"
      Console.WriteLine("Writable Collection (after changing one value):")
      PrintKeysAndValues(myRWCol)

      ' Removes one item from the collection.
      myRWCol.Remove("black")
      Console.WriteLine("Writable Collection (after removing one value):")
      PrintKeysAndValues(myRWCol)

      ' Removes all elements from the collection.
      myRWCol.Clear()
      Console.WriteLine("Writable Collection (after clearing the collection):")
      PrintKeysAndValues(myRWCol)

   End Sub

   ' Prints the indexes, keys, and values.
   Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
      Dim i As Integer
      For i = 0 To myCol.Count - 1
         Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
      Next i
   End Sub

   ' Prints the keys and values using AllKeys.
   Public Shared Sub PrintKeysAndValues2(myCol As MyCollection)
      Dim s As String
      For Each s In  myCol.AllKeys
         Console.WriteLine("{0}, {1}", s, myCol(s))
      Next s
   End Sub

End Class


'This code produces the following output.
'
'System.NotSupportedException: Collection is read-only.
'   at System.Collections.Specialized.NameObjectCollectionBase.BaseAdd(String name, Object value)
'   at SamplesNameObjectCollectionBase.Main()
'Read-Only Collection:
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'Writable Collection (after adding values):
'[0] : purple, grape
'[1] : orange, tangerine
'[2] : black, berries
'Writable Collection (after changing one value):
'[0] : purple, grape
'[1] : orange, grapefruit
'[2] : black, berries
'Writable Collection (after removing one value):
'[0] : purple, grape
'[1] : orange, grapefruit
'Writable Collection (after clearing the collection):

注解

此类的基础结构是哈希表。

每个元素都是一个键/值对。

的 NameObjectCollectionBase 容量是 可以容纳的元素 NameObjectCollectionBase 数。 将元素添加到 时 NameObjectCollectionBase，容量会根据需要通过重新分配自动增加。

哈希代码提供程序为 实例中的 NameObjectCollectionBase 键分配哈希代码。 默认哈希代码提供程序为 CaseInsensitiveHashCodeProvider。

比较器确定两个键是否相等。 默认比较器为 CaseInsensitiveComparer。

在 .NET Framework 版本 1.0 中，此类使用区分区域性的字符串比较。 但是，在 .NET Framework 版本 1.1 及更高版本中，此类在比较字符串时使用 CultureInfo.InvariantCulture 。 有关区域性如何影响比较和排序的详细信息，请参阅 执行 Culture-Insensitive 字符串操作。

null 允许作为键或值。

注意

方法 BaseGet 不区分 null 因找不到指定的键而返回的和 null 返回的，因为与键 null关联的值为 。

构造函数

NameObjectCollectionBase()	初始化为空的 NameObjectCollectionBase 类的新实例。
NameObjectCollectionBase(IEqualityComparer)	初始化 NameObjectCollectionBase 类的新实例，该实例为空、具有默认的初始容量并使用指定的 IEqualityComparer 对象。
NameObjectCollectionBase(IHashCodeProvider, IComparer)	已过时. 初始化 NameObjectCollectionBase 类的新实例，该实例为空、具有默认初始容量，并使用指定的哈希代码提供程序和指定的比较器。
NameObjectCollectionBase(Int32)	初始化 NameObjectCollectionBase 类的新实例，该实例为空、具有指定的初始容量，并使用默认哈希代码提供程序和默认比较器。
NameObjectCollectionBase(Int32, IEqualityComparer)	初始化 NameObjectCollectionBase 类的新实例，该实例为空、具有指定的初始容量并使用指定的 IEqualityComparer 对象。
NameObjectCollectionBase(Int32, IHashCodeProvider, IComparer)	已过时. 初始化 NameObjectCollectionBase 类的新实例，该实例为空且具有指定的初始容量，并使用指定的哈希代码提供程序和指定的比较器。
NameObjectCollectionBase(SerializationInfo, StreamingContext)	已过时. 初始化 NameObjectCollectionBase 类的新实例，该实例可序列化且使用指定的 SerializationInfo 和 StreamingContext。

属性

Count	获取包含在 NameObjectCollectionBase 实例中的键/值对的数目。
IsReadOnly	获取或设置一个值，通过该值指示 NameObjectCollectionBase 实例是否为只读的。
Keys	获取包含 NameObjectCollectionBase.KeysCollection 实例中所有键的 NameObjectCollectionBase 实例。

方法

BaseAdd(String, Object)	将具有指定键和值的项添加到 NameObjectCollectionBase 实例中。
BaseClear()	移除 NameObjectCollectionBase 实例中的所有项。
BaseGet(Int32)	获取 NameObjectCollectionBase 实例的指定索引处的项值。
BaseGet(String)	获取 NameObjectCollectionBase 实例中第一个具有指定键的项值。
BaseGetAllKeys()	返回 String 数组，该数组包含 NameObjectCollectionBase 实例中的所有键。
BaseGetAllValues()	返回 Object 数组，该数组包含 NameObjectCollectionBase 实例中的所有值。
BaseGetAllValues(Type)	返回指定类型的数组，该数组包含 NameObjectCollectionBase 实例中的所有值。
BaseGetKey(Int32)	获取 NameObjectCollectionBase 实例的指定索引处的项键。
BaseHasKeys()	获取一个值，通过该值指示 NameObjectCollectionBase 实例是否包含键不为 null 的项。
BaseRemove(String)	移除 NameObjectCollectionBase 实例中具有指定键的项。
BaseRemoveAt(Int32)	移除 NameObjectCollectionBase 实例的指定索引处的项。
BaseSet(Int32, Object)	设置 NameObjectCollectionBase 实例的指定索引处的项值。
BaseSet(String, Object)	为 NameObjectCollectionBase 实例中第一个具有指定键的项设置值（如果有这样的项）；否则将具有指定键和值的项添加到 NameObjectCollectionBase 实例中。
Equals(Object)	确定指定对象是否等于当前对象。 (继承自 Object)
GetEnumerator()	返回循环访问 NameObjectCollectionBase 的枚举数。
GetHashCode()	作为默认哈希函数。 (继承自 Object)
GetObjectData(SerializationInfo, StreamingContext)	已过时. 实现 ISerializable 接口，并返回序列化 NameObjectCollectionBase 实例所需的数据。
GetType()	获取当前实例的 Type。 (继承自 Object)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
OnDeserialization(Object)	实现 ISerializable 接口，并在完成反序列化之后引发反序列化事件。
ToString()	返回表示当前对象的字符串。 (继承自 Object)

显式接口实现

ICollection.CopyTo(Array, Int32)	从目标数组的指定索引处开始将整个 NameObjectCollectionBase 复制到兼容的一维 Array。
ICollection.IsSynchronized	获取一个值，该值指示对 NameObjectCollectionBase 对象的访问是否同步（线程安全）。
ICollection.SyncRoot	获取一个对象，该对象可用于同步对 NameObjectCollectionBase 对象的访问。

扩展方法

Cast<TResult>(IEnumerable)	将 IEnumerable 的元素强制转换为指定的类型。
OfType<TResult>(IEnumerable)	根据指定类型筛选 IEnumerable 的元素。
AsParallel(IEnumerable)	启用查询的并行化。
AsQueryable(IEnumerable)	将 IEnumerable 转换为 IQueryable。

线程安全性

Visual Basic 中的公共静态 (Shared) 此类型的成员是线程安全的。 但不保证所有实例成员都是线程安全的。

此实现不会为 NameObjectCollectionBase提供同步 (线程安全) 包装器，但派生类可以使用 属性创建自己的同步版本的 NameObjectCollectionBaseSyncRoot 。

通过集合枚举本质上不是线程安全的过程。 即使某个集合已同步，其他线程仍可以修改该集合，这会导致枚举数引发异常。 若要确保枚举过程中的线程安全性，可以在整个枚举期间锁定集合，或者捕获由其他线程进行的更改所导致的异常。

另请参阅

• Hashtable
• NameValueCollection
• String
• 执行不区分区域性的字符串操作