DictionaryBase 类
定义
重要
一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。 对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。
abstract为键/值对的强类型集合提供基类。
public ref class DictionaryBase abstract : System::Collections::IDictionarypublic abstract class DictionaryBase : System.Collections.IDictionary[System.Serializable]
public abstract class DictionaryBase : System.Collections.IDictionary[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public abstract class DictionaryBase : System.Collections.IDictionarytype DictionaryBase = class
interface ICollection
interface IEnumerable
interface IDictionary[<System.Serializable>]
type DictionaryBase = class
interface IDictionary
interface ICollection
interface IEnumerable[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type DictionaryBase = class
interface IDictionary
interface ICollection
interface IEnumerablePublic MustInherit Class DictionaryBase
Implements IDictionary- 继承
-
DictionaryBase
- 派生
- 属性
- 实现
示例
下面的代码示例实现 DictionaryBase 该类，并使用该实现创建键和值字典 String ，这些键和值包含 Length 5 个字符或更少。
using System;
using System.Collections;
public class ShortStringDictionary : DictionaryBase {
public String this[ String key ] {
get {
return( (String) Dictionary[key] );
}
set {
Dictionary[key] = value;
}
}
public ICollection Keys {
get {
return( Dictionary.Keys );
}
}
public ICollection Values {
get {
return( Dictionary.Values );
}
}
public void Add( String key, String value ) {
Dictionary.Add( key, value );
}
public bool Contains( String key ) {
return( Dictionary.Contains( key ) );
}
public void Remove( String key ) {
Dictionary.Remove( key );
}
protected override void OnInsert( Object key, Object value ) {
if ( key.GetType() != typeof(System.String) )
{
throw new ArgumentException( "key must be of type String.", "key" );
}
else {
String strKey = (String) key;
if ( strKey.Length > 5 )
throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
}
if ( value.GetType() != typeof(System.String) )
{
throw new ArgumentException( "value must be of type String.", "value" );
}
else {
String strValue = (String) value;
if ( strValue.Length > 5 )
throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );
}
}
protected override void OnRemove( Object key, Object value ) {
if ( key.GetType() != typeof(System.String) )
{
throw new ArgumentException( "key must be of type String.", "key" );
}
else {
String strKey = (String) key;
if ( strKey.Length > 5 )
throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
}
}
protected override void OnSet( Object key, Object oldValue, Object newValue ) {
if ( key.GetType() != typeof(System.String) )
{
throw new ArgumentException( "key must be of type String.", "key" );
}
else {
String strKey = (String) key;
if ( strKey.Length > 5 )
throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
}
if ( newValue.GetType() != typeof(System.String) )
{
throw new ArgumentException( "newValue must be of type String.", "newValue" );
}
else {
String strValue = (String) newValue;
if ( strValue.Length > 5 )
throw new ArgumentException( "newValue must be no more than 5 characters in length.", "newValue" );
}
}
protected override void OnValidate( Object key, Object value ) {
if ( key.GetType() != typeof(System.String) )
{
throw new ArgumentException( "key must be of type String.", "key" );
}
else {
String strKey = (String) key;
if ( strKey.Length > 5 )
throw new ArgumentException( "key must be no more than 5 characters in length.", "key" );
}
if ( value.GetType() != typeof(System.String) )
{
throw new ArgumentException( "value must be of type String.", "value" );
}
else {
String strValue = (String) value;
if ( strValue.Length > 5 )
throw new ArgumentException( "value must be no more than 5 characters in length.", "value" );
}
}
}
public class SamplesDictionaryBase {
public static void Main() {
// Creates and initializes a new DictionaryBase.
ShortStringDictionary mySSC = new ShortStringDictionary();
// Adds elements to the collection.
mySSC.Add( "One", "a" );
mySSC.Add( "Two", "ab" );
mySSC.Add( "Three", "abc" );
mySSC.Add( "Four", "abcd" );
mySSC.Add( "Five", "abcde" );
// Display the contents of the collection using foreach. This is the preferred method.
Console.WriteLine( "Contents of the collection (using foreach):" );
PrintKeysAndValues1( mySSC );
// Display the contents of the collection using the enumerator.
Console.WriteLine( "Contents of the collection (using enumerator):" );
PrintKeysAndValues2( mySSC );
// Display the contents of the collection using the Keys property and the Item property.
Console.WriteLine( "Initial contents of the collection (using Keys and Item):" );
PrintKeysAndValues3( mySSC );
// Tries to add a value that is too long.
try {
mySSC.Add( "Ten", "abcdefghij" );
}
catch ( ArgumentException e ) {
Console.WriteLine( e.ToString() );
}
// Tries to add a key that is too long.
try {
mySSC.Add( "Eleven", "ijk" );
}
catch ( ArgumentException e ) {
Console.WriteLine( e.ToString() );
}
Console.WriteLine();
// Searches the collection with Contains.
Console.WriteLine( "Contains \"Three\": {0}", mySSC.Contains( "Three" ) );
Console.WriteLine( "Contains \"Twelve\": {0}", mySSC.Contains( "Twelve" ) );
Console.WriteLine();
// Removes an element from the collection.
mySSC.Remove( "Two" );
// Displays the contents of the collection.
Console.WriteLine( "After removing \"Two\":" );
PrintKeysAndValues1( mySSC );
}
// 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( ShortStringDictionary myCol ) {
foreach ( DictionaryEntry myDE in myCol )
Console.WriteLine( " {0,-5} : {1}", myDE.Key, myDE.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( ShortStringDictionary myCol ) {
DictionaryEntry myDE;
System.Collections.IEnumerator myEnumerator = myCol.GetEnumerator();
while ( myEnumerator.MoveNext() )
if ( myEnumerator.Current != null ) {
myDE = (DictionaryEntry) myEnumerator.Current;
Console.WriteLine( " {0,-5} : {1}", myDE.Key, myDE.Value );
}
Console.WriteLine();
}
// Uses the Keys property and the Item property.
public static void PrintKeysAndValues3( ShortStringDictionary myCol ) {
ICollection myKeys = myCol.Keys;
foreach ( String k in myKeys )
Console.WriteLine( " {0,-5} : {1}", k, myCol[k] );
Console.WriteLine();
}
}
/*
This code produces the following output.
Contents of the collection (using foreach):
Three : abc
Five : abcde
Two : ab
One : a
Four : abcd
Contents of the collection (using enumerator):
Three : abc
Five : abcde
Two : ab
One : a
Four : abcd
Initial contents of the collection (using Keys and Item):
Three : abc
Five : abcde
Two : ab
One : a
Four : abcd
System.ArgumentException: value must be no more than 5 characters in length.
Parameter name: value
at ShortStringDictionary.OnValidate(Object key, Object value)
at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
at SamplesDictionaryBase.Main()
System.ArgumentException: key must be no more than 5 characters in length.
Parameter name: key
at ShortStringDictionary.OnValidate(Object key, Object value)
at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
at SamplesDictionaryBase.Main()
Contains "Three": True
Contains "Twelve": False
After removing "Two":
Three : abc
Five : abcde
One : a
Four : abcd
*/
Imports System.Collections
Public Class ShortStringDictionary
Inherits DictionaryBase
Default Public Property Item(key As String) As String
Get
Return CType(Dictionary(key), String)
End Get
Set
Dictionary(key) = value
End Set
End Property
Public ReadOnly Property Keys() As ICollection
Get
Return Dictionary.Keys
End Get
End Property
Public ReadOnly Property Values() As ICollection
Get
Return Dictionary.Values
End Get
End Property
Public Sub Add(key As String, value As String)
Dictionary.Add(key, value)
End Sub
Public Function Contains(key As String) As Boolean
Return Dictionary.Contains(key)
End Function 'Contains
Public Sub Remove(key As String)
Dictionary.Remove(key)
End Sub
Protected Overrides Sub OnInsert(key As Object, value As Object)
If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
Throw New ArgumentException("key must be of type String.", "key")
Else
Dim strKey As String = CType(key, String)
If strKey.Length > 5 Then
Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
End If
End If
If Not GetType(System.String).IsAssignableFrom(value.GetType()) Then
Throw New ArgumentException("value must be of type String.", "value")
Else
Dim strValue As String = CType(value, String)
If strValue.Length > 5 Then
Throw New ArgumentException("value must be no more than 5 characters in length.", "value")
End If
End If
End Sub
Protected Overrides Sub OnRemove(key As Object, value As Object)
If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
Throw New ArgumentException("key must be of type String.", "key")
Else
Dim strKey As String = CType(key, String)
If strKey.Length > 5 Then
Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
End If
End If
End Sub
Protected Overrides Sub OnSet(key As Object, oldValue As Object, newValue As Object)
If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
Throw New ArgumentException("key must be of type String.", "key")
Else
Dim strKey As String = CType(key, String)
If strKey.Length > 5 Then
Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
End If
End If
If Not GetType(System.String).IsAssignableFrom(newValue.GetType()) Then
Throw New ArgumentException("newValue must be of type String.", "newValue")
Else
Dim strValue As String = CType(newValue, String)
If strValue.Length > 5 Then
Throw New ArgumentException("newValue must be no more than 5 characters in length.", "newValue")
End If
End If
End Sub
Protected Overrides Sub OnValidate(key As Object, value As Object)
If Not GetType(System.String).IsAssignableFrom(key.GetType()) Then
Throw New ArgumentException("key must be of type String.", "key")
Else
Dim strKey As String = CType(key, String)
If strKey.Length > 5 Then
Throw New ArgumentException("key must be no more than 5 characters in length.", "key")
End If
End If
If Not GetType(System.String).IsAssignableFrom(value.GetType()) Then
Throw New ArgumentException("value must be of type String.", "value")
Else
Dim strValue As String = CType(value, String)
If strValue.Length > 5 Then
Throw New ArgumentException("value must be no more than 5 characters in length.", "value")
End If
End If
End Sub
End Class
Public Class SamplesDictionaryBase
Public Shared Sub Main()
' Creates and initializes a new DictionaryBase.
Dim mySSC As New ShortStringDictionary()
' Adds elements to the collection.
mySSC.Add("One", "a")
mySSC.Add("Two", "ab")
mySSC.Add("Three", "abc")
mySSC.Add("Four", "abcd")
mySSC.Add("Five", "abcde")
' Display the contents of the collection using For Each. This is the preferred method.
Console.WriteLine("Contents of the collection (using For Each):")
PrintKeysAndValues1(mySSC)
' Display the contents of the collection using the enumerator.
Console.WriteLine("Contents of the collection (using enumerator):")
PrintKeysAndValues2(mySSC)
' Display the contents of the collection using the Keys property and the Item property.
Console.WriteLine("Initial contents of the collection (using Keys and Item):")
PrintKeysAndValues3(mySSC)
' Tries to add a value that is too long.
Try
mySSC.Add("Ten", "abcdefghij")
Catch e As ArgumentException
Console.WriteLine(e.ToString())
End Try
' Tries to add a key that is too long.
Try
mySSC.Add("Eleven", "ijk")
Catch e As ArgumentException
Console.WriteLine(e.ToString())
End Try
Console.WriteLine()
' Searches the collection with Contains.
Console.WriteLine("Contains ""Three"": {0}", mySSC.Contains("Three"))
Console.WriteLine("Contains ""Twelve"": {0}", mySSC.Contains("Twelve"))
Console.WriteLine()
' Removes an element from the collection.
mySSC.Remove("Two")
' Displays the contents of the collection.
Console.WriteLine("After removing ""Two"":")
PrintKeysAndValues1(mySSC)
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 ShortStringDictionary)
Dim myDE As DictionaryEntry
For Each myDE In myCol
Console.WriteLine(" {0,-5} : {1}", myDE.Key, myDE.Value)
Next myDE
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 ShortStringDictionary)
Dim myDE As DictionaryEntry
Dim myEnumerator As System.Collections.IEnumerator = myCol.GetEnumerator()
While myEnumerator.MoveNext()
If Not (myEnumerator.Current Is Nothing) Then
myDE = CType(myEnumerator.Current, DictionaryEntry)
Console.WriteLine(" {0,-5} : {1}", myDE.Key, myDE.Value)
End If
End While
Console.WriteLine()
End Sub
' Uses the Keys property and the Item property.
Public Shared Sub PrintKeysAndValues3(myCol As ShortStringDictionary)
Dim myKeys As ICollection = myCol.Keys
Dim k As String
For Each k In myKeys
Console.WriteLine(" {0,-5} : {1}", k, myCol(k))
Next k
Console.WriteLine()
End Sub
End Class
'This code produces the following output.
'
'Contents of the collection (using For Each):
' Three : abc
' Five : abcde
' Two : ab
' One : a
' Four : abcd
'
'Contents of the collection (using enumerator):
' Three : abc
' Five : abcde
' Two : ab
' One : a
' Four : abcd
'
'Initial contents of the collection (using Keys and Item):
' Three : abc
' Five : abcde
' Two : ab
' One : a
' Four : abcd
'
'System.ArgumentException: value must be no more than 5 characters in length.
'Parameter name: value
' at ShortStringDictionary.OnValidate(Object key, Object value)
' at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
' at SamplesDictionaryBase.Main()
'System.ArgumentException: key must be no more than 5 characters in length.
'Parameter name: key
' at ShortStringDictionary.OnValidate(Object key, Object value)
' at System.Collections.DictionaryBase.System.Collections.IDictionary.Add(Object key, Object value)
' at SamplesDictionaryBase.Main()
'
'Contains "Three": True
'Contains "Twelve": False
'
'After removing "Two":
' Three : abc
' Five : abcde
' One : a
' Four : abcd
注解
重要
不建议将 DictionaryBase 类用于新开发。 相反，我们建议使用泛型 Dictionary<TKey,TValue> 或 KeyedCollection<TKey,TItem> 类。 有关详细信息，请参阅不应在 GitHub 上使用 非泛型集合 。
C# foreach 语句和 Visual Basic For Each 语句返回集合中元素类型的对象。 由于每个元素都是键/值对，因此元素 DictionaryBase 类型不是键的类型或值的类型。 相反，元素类型为 DictionaryEntry.
该 foreach 语句是枚举器周围的包装器，它只允许从集合（而不是写入到集合）进行读取。
Note
由于可以继承密钥并更改其行为，因此使用该方法的比较 Equals 无法保证其绝对唯一性。
实施者说明
提供了此基类，以便实现者更轻松地创建强类型自定义集合。 鼓励实现者扩展此基类，而不是创建自己的基类。
此基类的成员受到保护，仅用于通过派生类使用。
构造函数
| 名称 | 说明 |
|---|---|
| DictionaryBase() |
初始化 DictionaryBase 类的新实例。 |
属性
| 名称 | 说明 |
|---|---|
| Count |
获取实例中包含的 DictionaryBase 元素数。 |
| Dictionary |
获取实例中包含的 DictionaryBase 元素列表。 |
| InnerHashtable |
获取实例中包含的 DictionaryBase 元素列表。 |
方法
| 名称 | 说明 |
|---|---|
| Clear() |
清除实例的内容 DictionaryBase 。 |
| CopyTo(Array, Int32) |
将 DictionaryBase 元素复制到指定索引处的一维 Array 。 |
| Equals(Object) |
确定指定对象是否等于当前对象。 (继承自 Object) |
| GetEnumerator() |
返回循环访问实例的IDictionaryEnumerator一个DictionaryBase。 |
| GetHashCode() |
用作默认哈希函数。 (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) |
| OnClear() |
在清除实例的内容 DictionaryBase 之前执行其他自定义过程。 |
| OnClearComplete() |
清除实例的内容 DictionaryBase 后，执行其他自定义进程。 |
| OnGet(Object, Object) |
获取实例中 DictionaryBase 具有指定键和值的元素。 |
| OnInsert(Object, Object) |
在将新元素 DictionaryBase 插入实例之前执行其他自定义过程。 |
| OnInsertComplete(Object, Object) |
在将新元素 DictionaryBase 插入实例后执行其他自定义进程。 |
| OnRemove(Object, Object) |
在从 DictionaryBase 实例中删除元素之前执行其他自定义过程。 |
| OnRemoveComplete(Object, Object) |
从 DictionaryBase 实例中删除元素后执行其他自定义进程。 |
| OnSet(Object, Object, Object) |
在实例中 DictionaryBase 设置值之前执行其他自定义过程。 |
| OnSetComplete(Object, Object, Object) |
在实例中 DictionaryBase 设置值后执行其他自定义进程。 |
| OnValidate(Object, Object) |
使用指定的键和值验证元素时执行其他自定义过程。 |
| ToString() |
返回一个表示当前对象的字符串。 (继承自 Object) |
显式接口实现
| 名称 | 说明 |
|---|---|
| ICollection.IsSynchronized |
获取一个值，该值指示是否同步对 DictionaryBase 对象的访问（线程安全）。 |
| ICollection.SyncRoot |
获取可用于同步对 DictionaryBase 对象的访问的对象。 |
| IDictionary.Add(Object, Object) |
将具有指定键和值的元素添加到 .DictionaryBase |
| IDictionary.Contains(Object) |
确定 DictionaryBase 是否包含特定密钥。 |
| IDictionary.IsFixedSize |
获取一个值，该值指示对象是否 DictionaryBase 具有固定大小。 |
| IDictionary.IsReadOnly |
获取一个值，该值指示对象 DictionaryBase 是否为只读。 |
| IDictionary.Item[Object] |
获取或设置与指定键关联的值。 |
| IDictionary.Keys |
获取一个 ICollection 对象，该对象包含对象 DictionaryBase 中的键。 |
| IDictionary.Remove(Object) |
从 中移除具有指定键的 DictionaryBase元素。 |
| IDictionary.Values |
获取一个 ICollection 对象，该对象包含对象 DictionaryBase 中的值。 |
| IEnumerable.GetEnumerator() |
返回循环访问的IEnumerator一个 DictionaryBase 。 |
扩展方法
| 名称 | 说明 |
|---|---|
| AsParallel(IEnumerable) |
启用查询的并行化。 |
| AsQueryable(IEnumerable) |
将 IEnumerable 转换为 IQueryable。 |
| Cast<TResult>(IEnumerable) |
将 IEnumerable 的元素强制转换为指定类型。 |
| OfType<TResult>(IEnumerable) |
根据指定类型筛选 IEnumerable 的元素。 |
适用于
线程安全性
此类型的公共静态（Shared 在 Visual Basic 中）成员是线程安全的。 不能保证任何实例成员是线程安全的。
此实现不提供同步的（线程安全）包装器，DictionaryBase但派生类可以创建其自己的使用属性的DictionaryBaseSyncRoot同步版本。
通过集合进行枚举本质上不是线程安全的过程。 即使集合同步，其他线程仍可以修改集合，这会导致枚举器引发异常。 若要保证枚举期间的线程安全性，可以在整个枚举期间锁定集合，也可以捕获由其他线程所做的更改导致的异常。
