StringDictionary 类

定义

使用字符串(而不是对象)强类型的键和值来实现哈希表。

public ref class StringDictionary : System::Collections::IEnumerable
public class StringDictionary : System.Collections.IEnumerable
[System.Serializable]
public class StringDictionary : System.Collections.IEnumerable
type StringDictionary = class
    interface IEnumerable
[<System.Serializable>]
type StringDictionary = class
    interface IEnumerable
Public Class StringDictionary
Implements IEnumerable
继承
StringDictionary
属性
实现

示例

下面的代码示例演示 的几个属性和方法 StringDictionary

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues2( StringDictionary^ myCol );
void PrintKeysAndValues3( StringDictionary^ myCol );

int main()
{
   // Creates and initializes a new StringDictionary.
   StringDictionary^ myCol = gcnew StringDictionary;
   myCol->Add( "red", "rojo" );
   myCol->Add( "green", "verde" );
   myCol->Add( "blue", "azul" );

   // Display the contents of the collection using the enumerator.
   Console::WriteLine( "Displays the elements using the IEnumerator:" );
   PrintKeysAndValues2( myCol );

   // Display the contents of the collection using the Keys, Values, Count, and Item properties.
   Console::WriteLine( "Displays the elements using the Keys, Values, Count, and Item properties:" );
   PrintKeysAndValues3( myCol );

   // Copies the StringDictionary to an array with DictionaryEntry elements.
   array<DictionaryEntry>^myArr = gcnew array<DictionaryEntry>(myCol->Count);
   myCol->CopyTo( myArr, 0 );

   // Displays the values in the array.
   Console::WriteLine( "Displays the elements in the array:" );
   Console::WriteLine( "   KEY        VALUE" );
   for ( int i = 0; i < myArr->Length; i++ )
      Console::WriteLine( "   {0,-10} {1}", myArr[ i ].Key, myArr[ i ].Value );
   Console::WriteLine();

   // Searches for a value.
   if ( myCol->ContainsValue( "amarillo" ) )
      Console::WriteLine( "The collection contains the value \"amarillo\"." );
   else
      Console::WriteLine( "The collection does not contain the value \"amarillo\"." );

   Console::WriteLine();
   
   // Searches for a key and deletes it.
   if ( myCol->ContainsKey( "green" ) )
      myCol->Remove( "green" );

   Console::WriteLine( "The collection contains the following elements after removing \"green\":" );
   PrintKeysAndValues2( myCol );

   // Clears the entire collection.
   myCol->Clear();
   Console::WriteLine( "The collection contains the following elements after it is cleared:" );
   PrintKeysAndValues2( myCol );
}

// Uses the enumerator. 
void PrintKeysAndValues2( StringDictionary^ myCol )
{
   IEnumerator^ myEnumerator = myCol->GetEnumerator();
   DictionaryEntry de;
   Console::WriteLine( "   KEY                       VALUE" );
   while ( myEnumerator->MoveNext() )
   {
      de =  *dynamic_cast<DictionaryEntry^>(myEnumerator->Current);
      Console::WriteLine( "   {0,-25} {1}", de.Key, de.Value );
   }

   Console::WriteLine();
}

// Uses the Keys, Values, Count, and Item properties.
void PrintKeysAndValues3( StringDictionary^ myCol )
{
   array<String^>^myKeys = gcnew array<String^>(myCol->Count);
   myCol->Keys->CopyTo( myKeys, 0 );
   Console::WriteLine( "   INDEX KEY                       VALUE" );
   for ( int i = 0; i < myCol->Count; i++ )
      Console::WriteLine( "   {0,-5} {1,-25} {2}", i, myKeys[ i ], myCol[ myKeys[ i ] ] );
   Console::WriteLine();
}

/*
This code produces the following output.

Displays the elements using the IEnumerator:
   KEY                       VALUE
   red                       rojo
   blue                      azul
   green                     verde

Displays the elements using the Keys, Values, Count, and Item properties:
   INDEX KEY                       VALUE
   0     red                       rojo
   1     blue                      azul
   2     green                     verde

Displays the elements in the array:
   KEY        VALUE
   red        rojo
   blue       azul
   green      verde

The collection does not contain the value "amarillo".

The collection contains the following elements after removing "green":
   KEY                       VALUE
   red                       rojo
   blue                      azul

The collection contains the following elements after it is cleared:
   KEY                       VALUE

*/
using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesStringDictionary  {

   public static void Main()  {

      // Creates and initializes a new StringDictionary.
      StringDictionary myCol = new StringDictionary();
      myCol.Add( "red", "rojo" );
      myCol.Add( "green", "verde" );
      myCol.Add( "blue", "azul" );

      // Display the contents of the collection using foreach. This is the preferred method.
      Console.WriteLine( "Displays the elements using foreach:" );
      PrintKeysAndValues1( myCol );

      // Display the contents of the collection using the enumerator.
      Console.WriteLine( "Displays the elements using the IEnumerator:" );
      PrintKeysAndValues2( myCol );

      // Display the contents of the collection using the Keys, Values, Count, and Item properties.
      Console.WriteLine( "Displays the elements using the Keys, Values, Count, and Item properties:" );
      PrintKeysAndValues3( myCol );

      // Copies the StringDictionary to an array with DictionaryEntry elements.
      DictionaryEntry[] myArr = new DictionaryEntry[myCol.Count];
      myCol.CopyTo( myArr, 0 );

      // Displays the values in the array.
      Console.WriteLine( "Displays the elements in the array:" );
      Console.WriteLine( "   KEY        VALUE" );
      for ( int i = 0; i < myArr.Length; i++ )
         Console.WriteLine( "   {0,-10} {1}", myArr[i].Key, myArr[i].Value );
      Console.WriteLine();

      // Searches for a value.
      if ( myCol.ContainsValue( "amarillo" ) )
         Console.WriteLine( "The collection contains the value \"amarillo\"." );
      else
         Console.WriteLine( "The collection does not contain the value \"amarillo\"." );
      Console.WriteLine();

      // Searches for a key and deletes it.
      if ( myCol.ContainsKey( "green" ) )
         myCol.Remove( "green" );
      Console.WriteLine( "The collection contains the following elements after removing \"green\":" );
      PrintKeysAndValues1( myCol );

      // Clears the entire collection.
      myCol.Clear();
      Console.WriteLine( "The collection contains the following elements after it is cleared:" );
      PrintKeysAndValues1( myCol );
   }

   // Uses the foreach statement which hides the complexity of the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintKeysAndValues1( StringDictionary myCol )  {
      Console.WriteLine( "   KEY                       VALUE" );
      foreach ( DictionaryEntry de in myCol )
         Console.WriteLine( "   {0,-25} {1}", de.Key, de.Value );
      Console.WriteLine();
   }

   // Uses the enumerator.
   // NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
   public static void PrintKeysAndValues2( StringDictionary myCol )  {
      IEnumerator myEnumerator = myCol.GetEnumerator();
      DictionaryEntry de;
      Console.WriteLine( "   KEY                       VALUE" );
      while ( myEnumerator.MoveNext() )  {
         de = (DictionaryEntry) myEnumerator.Current;
         Console.WriteLine( "   {0,-25} {1}", de.Key, de.Value );
      }
      Console.WriteLine();
   }

   // Uses the Keys, Values, Count, and Item properties.
   public static void PrintKeysAndValues3( StringDictionary myCol )  {
      String[] myKeys = new String[myCol.Count];
      myCol.Keys.CopyTo( myKeys, 0 );

      Console.WriteLine( "   INDEX KEY                       VALUE" );
      for ( int i = 0; i < myCol.Count; i++ )
         Console.WriteLine( "   {0,-5} {1,-25} {2}", i, myKeys[i], myCol[myKeys[i]] );
      Console.WriteLine();
   }
}

/*
This code produces the following output.

Displays the elements using foreach:
   KEY                       VALUE
   red                       rojo
   blue                      azul
   green                     verde

Displays the elements using the IEnumerator:
   KEY                       VALUE
   red                       rojo
   blue                      azul
   green                     verde

Displays the elements using the Keys, Values, Count, and Item properties:
   INDEX KEY                       VALUE
   0     red                       rojo
   1     blue                      azul
   2     green                     verde

Displays the elements in the array:
   KEY        VALUE
   red        rojo
   blue       azul
   green      verde

The collection does not contain the value "amarillo".

The collection contains the following elements after removing "green":
   KEY                       VALUE
   red                       rojo
   blue                      azul

The collection contains the following elements after it is cleared:
   KEY                       VALUE

*/
Imports System.Collections
Imports System.Collections.Specialized

Public Class SamplesStringDictionary   

   Public Shared Sub Main()

      ' Creates and initializes a new StringDictionary.
      Dim myCol As New StringDictionary()
      myCol.Add("red", "rojo")
      myCol.Add("green", "verde")
      myCol.Add("blue", "azul")

      ' Display the contents of the collection using For Each. This is the preferred method.
      Console.WriteLine("Displays the elements using For Each:")
      PrintKeysAndValues1(myCol)

      ' Display the contents of the collection using the enumerator.
      Console.WriteLine("Displays the elements using the IEnumerator:")
      PrintKeysAndValues2(myCol)

      ' Display the contents of the collection using the Keys, Values, Count, and Item properties.
      Console.WriteLine("Displays the elements using the Keys, Values, Count, and Item properties:")
      PrintKeysAndValues3(myCol)

      ' Copies the StringDictionary to an array with DictionaryEntry elements.
      Dim myArr(myCol.Count) As DictionaryEntry
      myCol.CopyTo(myArr, 0)

      ' Displays the values in the array.
      Console.WriteLine("Displays the elements in the array:")
      Console.WriteLine("   KEY        VALUE")
      Dim i As Integer
      For i = 0 To myArr.Length - 1
         Console.WriteLine("   {0,-10} {1}", myArr(i).Key, myArr(i).Value)
      Next i
      Console.WriteLine()

      ' Searches for a value.
      If myCol.ContainsValue("amarillo") Then
         Console.WriteLine("The collection contains the value ""amarillo"".")
      Else
         Console.WriteLine("The collection does not contain the value ""amarillo"".")
      End If
      Console.WriteLine()

      ' Searches for a key and deletes it.
      If myCol.ContainsKey("green") Then
         myCol.Remove("green")
      End If
      Console.WriteLine("The collection contains the following elements after removing ""green"":")
      PrintKeysAndValues1(myCol)

      ' Clears the entire collection.
      myCol.Clear()
      Console.WriteLine("The collection contains the following elements after it is cleared:")
      PrintKeysAndValues1(myCol)

   End Sub


   ' Uses the For Each statement which hides the complexity of the enumerator.
   ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
   Public Shared Sub PrintKeysAndValues1(myCol As StringDictionary)
      Console.WriteLine("   KEY                       VALUE")
      Dim de As DictionaryEntry
      For Each de In  myCol
         Console.WriteLine("   {0,-25} {1}", de.Key, de.Value)
      Next de
      Console.WriteLine()
   End Sub


   ' Uses the enumerator. 
   ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection.
   Public Shared Sub PrintKeysAndValues2(myCol As StringDictionary)
      Dim myEnumerator As IEnumerator = myCol.GetEnumerator()
      Dim de As DictionaryEntry
      Console.WriteLine("   KEY                       VALUE")
      While myEnumerator.MoveNext()
         de = CType(myEnumerator.Current, DictionaryEntry)
         Console.WriteLine("   {0,-25} {1}", de.Key, de.Value)
      End While
      Console.WriteLine()
   End Sub


   ' Uses the Keys, Values, Count, and Item properties.
   Public Shared Sub PrintKeysAndValues3(myCol As StringDictionary)
      Dim myKeys(myCol.Count) As String
      myCol.Keys.CopyTo(myKeys, 0)

      Console.WriteLine("   INDEX KEY                       VALUE")
      Dim i As Integer
      For i = 0 To myCol.Count - 1
         Console.WriteLine("   {0,-5} {1,-25} {2}", i, myKeys(i), myCol(myKeys(i)))
      Next i
      Console.WriteLine()
   End Sub

End Class


'This code produces the following output.
'
'Displays the elements using For Each:
'   KEY                       VALUE
'   red                       rojo
'   blue                      azul
'   green                     verde
'
'Displays the elements using the IEnumerator:
'   KEY                       VALUE
'   red                       rojo
'   blue                      azul
'   green                     verde
'
'Displays the elements using the Keys, Values, Count, and Item properties:
'   INDEX KEY                       VALUE
'   0     red                       rojo
'   1     blue                      azul
'   2     green                     verde
'
'Displays the elements in the array:
'   KEY        VALUE
'   red        rojo
'   blue       azul
'   green      verde
'
'
'The collection does not contain the value "amarillo".
'
'The collection contains the following elements after removing "green":
'   KEY                       VALUE
'   red                       rojo
'   blue                      azul
'
'The collection contains the following elements after it is cleared:
'   KEY                       VALUE

注解

键不能是 null,但值可以。

以不区分大小写的方式处理密钥;在将其与字符串字典一起使用之前,它将被转换为小写。

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

构造函数

StringDictionary()

初始化 StringDictionary 类的新实例。

属性

Count

获取 StringDictionary 中的键/值对的数目。

IsSynchronized

获取一个值,该值指示是否同步对 StringDictionary 的访问(线程安全)。

Item[String]

获取或设置与指定的键关联的值。

Keys

获取 StringDictionary 中键的集合。

SyncRoot

获取可用于同步对 StringDictionary 的访问的对象。

Values

获取 StringDictionary 中值的集合。

方法

Add(String, String)

将带有指定键和值的条目添加到 StringDictionary 中。

Clear()

StringDictionary 中移除所有项。

ContainsKey(String)

确定 StringDictionary 是否包含特定键。

ContainsValue(String)

确定 StringDictionary 是否包含特定值。

CopyTo(Array, Int32)

将字符串字典值复制到一维 Array 实例的指定索引位置。

Equals(Object)

确定指定对象是否等于当前对象。

(继承自 Object)
GetEnumerator()

返回循环访问字符串字典的枚举数。

GetHashCode()

作为默认哈希函数。

(继承自 Object)
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)
Remove(String)

从字符串字典中移除带有指定键的条目。

ToString()

返回表示当前对象的字符串。

(继承自 Object)

扩展方法

Cast<TResult>(IEnumerable)

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)

IEnumerable 转换为 IQueryable

适用于

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 StringDictionary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 StringDictionarySyncRoot

枚举整个集合本质上不是一个线程安全的过程。 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