DictionaryBase.GetEnumerator-Methode
Gibt einen IDictionaryEnumerator zurück, der die DictionaryBase-Instanz durchläuft.
Namespace: System.Collections
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Function GetEnumerator As IDictionaryEnumerator
'Usage
Dim instance As DictionaryBase
Dim returnValue As IDictionaryEnumerator
returnValue = instance.GetEnumerator
public IDictionaryEnumerator GetEnumerator ()
public:
virtual IDictionaryEnumerator^ GetEnumerator () sealed
public final IDictionaryEnumerator GetEnumerator ()
public final function GetEnumerator () : IDictionaryEnumerator
Rückgabewert
Ein IDictionaryEnumerator für die DictionaryBase-Instanz.
Hinweise
Die foreach-Anweisung der Programmiersprache C# (for each in Visual Basic) verbirgt die Komplexität der Enumeratoren. Daher wird empfohlen, foreach zu verwenden und den Enumerator nicht direkt zu bearbeiten.
Mit Enumeratoren können die Daten in der Auflistung gelesen werden, sie können jedoch nicht zum Ändern der zugrunde liegenden Auflistung verwendet werden.
Anfangs wird der Enumerator vor dem ersten Element in der Auflistung positioniert. Reset setzt den Enumerator ebenfalls auf diese Position zurück. An dieser Position ist Current nicht definiert. Daher muss der Enumerator durch das Aufrufen von MoveNext auf das erste Element der Auflistung festgelegt werden, bevor der Wert von Current gelesen werden kann.
Current gibt so lange dasselbe Objekt zurück, bis MoveNext oder Reset aufgerufen wird. MoveNext legt Current auf das nächste Element fest.
Wenn MoveNext das Ende der Auflistung erreicht, wird der Enumerator nach dem letzten Element in der Auflistung positioniert, und MoveNext gibt false zurück. Wenn sich der Enumerator an dieser Position befindet, geben nachfolgende Aufrufe von MoveNext ebenfalls false zurück. Wenn beim letzten Aufruf von MoveNextfalse zurückgegeben wurde, ist Current nicht definiert. Um Current wieder auf das erste Element der Auflistung festzulegen, können Sie Reset gefolgt von MoveNext aufrufen.
Ein Enumerator bleibt so lange gültig, bis die Auflistung geändert wird. Wenn an der Auflistung Änderungen vorgenommen werden, z. B. durch Hinzufügen, Ändern oder Löschen von Elementen, ist der Enumerator unwiderruflich ungültig und das zugehörige Verhalten nicht definiert.
Der Enumerator hat keinen exklusiven Zugriff auf die Auflistung. Daher ist die Enumeration einer Auflistung systemintern keine threadsichere Prozedur. Um Threadsicherheit während der Enumeration zu gewährleisten, können Sie die Auflistung während der gesamten Enumeration sperren. Um den Lese- und Schreibzugriff auf diese Auflistung durch mehrere Threads zuzulassen, müssen Sie eine eigene Synchronisierung implementieren.
Diese Methode ist eine O(1)-Operation.
Beispiel
Im folgenden Codebeispiel wird die DictionaryBase-Klasse implementiert und diese Implementierung zum Erstellen eines Wörterbuchs aus String-Schlüsseln und -Werten mit einer Length von höchstens 5 Zeichen verwendet.
Imports System
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 'Add
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 'Remove
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 'OnInsert
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 'OnRemove
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 'OnSet
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 'OnValidate
End Class 'ShortStringDictionary
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 'Main
' 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 'PrintKeysAndValues1
' 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 'PrintKeysAndValues2
' 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 'PrintKeysAndValues3
End Class 'SamplesDictionaryBase
'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
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
*/
using namespace System;
using namespace System::Collections;
public ref class ShortStringDictionary: public DictionaryBase
{
public:
property String^ Item [String^]
{
String^ get( String^ key )
{
return (dynamic_cast<String^>(Dictionary[ key ]));
}
void set( String^ value, String^ key )
{
Dictionary[ key ] = value;
}
}
property ICollection^ Keys
{
ICollection^ get()
{
return (Dictionary->Keys);
}
}
property ICollection^ Values
{
ICollection^ get()
{
return (Dictionary->Values);
}
}
void Add( String^ key, String^ value )
{
Dictionary->Add( key, value );
}
bool Contains( String^ key )
{
return (Dictionary->Contains( key ));
}
void Remove( String^ key )
{
Dictionary->Remove( key );
}
protected:
virtual void OnInsert( Object^ key, Object^ value ) override
{
if ( key->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "key must be of type String.","key" );
else
{
String^ strKey = dynamic_cast<String^>(key);
if ( strKey->Length > 5 )
throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
}
if ( value->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "value must be of type String.","value" );
else
{
String^ strValue = dynamic_cast<String^>(value);
if ( strValue->Length > 5 )
throw gcnew ArgumentException( "value must be no more than 5 characters in length.","value" );
}
}
virtual void OnRemove( Object^ key, Object^ /*value*/ ) override
{
if ( key->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "key must be of type String.","key" );
else
{
String^ strKey = dynamic_cast<String^>(key);
if ( strKey->Length > 5 )
throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
}
}
virtual void OnSet( Object^ key, Object^ /*oldValue*/, Object^ newValue ) override
{
if ( key->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "key must be of type String.","key" );
else
{
String^ strKey = dynamic_cast<String^>(key);
if ( strKey->Length > 5 )
throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
}
if ( newValue->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "newValue must be of type String.","newValue" );
else
{
String^ strValue = dynamic_cast<String^>(newValue);
if ( strValue->Length > 5 )
throw gcnew ArgumentException( "newValue must be no more than 5 characters in length.","newValue" );
}
}
virtual void OnValidate( Object^ key, Object^ value ) override
{
if ( key->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "key must be of type String.","key" );
else
{
String^ strKey = dynamic_cast<String^>(key);
if ( strKey->Length > 5 )
throw gcnew ArgumentException( "key must be no more than 5 characters in length.","key" );
}
if ( value->GetType() != Type::GetType( "System.String" ) )
throw gcnew ArgumentException( "value must be of type String.","value" );
else
{
String^ strValue = dynamic_cast<String^>(value);
if ( strValue->Length > 5 )
throw gcnew ArgumentException( "value must be no more than 5 characters in length.","value" );
}
}
};
void PrintKeysAndValues2( ShortStringDictionary^ myCol );
void PrintKeysAndValues3( ShortStringDictionary^ myCol );
int main()
{
// Creates and initializes a new DictionaryBase.
ShortStringDictionary^ mySSC = gcnew 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 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 );
}
// Tries to add a key that is too long.
try
{
mySSC->Add( "Eleven", "ijk" );
}
catch ( ArgumentException^ e )
{
Console::WriteLine( e );
}
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\":" );
PrintKeysAndValues2( mySSC );
}
// Uses the enumerator.
void PrintKeysAndValues2( ShortStringDictionary^ myCol )
{
DictionaryEntry myDE;
System::Collections::IEnumerator^ myEnumerator = myCol->GetEnumerator();
while ( myEnumerator->MoveNext() )
if ( myEnumerator->Current != nullptr )
{
myDE = *dynamic_cast<DictionaryEntry^>(myEnumerator->Current);
Console::WriteLine( " {0,-5} : {1}", myDE.Key, myDE.Value );
}
Console::WriteLine();
}
// Uses the Keys property and the Item property.
void PrintKeysAndValues3( ShortStringDictionary^ myCol )
{
ICollection^ myKeys = myCol->Keys;
IEnumerator^ myEnum1 = myKeys->GetEnumerator();
while ( myEnum1->MoveNext() )
{
String^ k = safe_cast<String^>(myEnum1->Current);
Console::WriteLine( " {0,-5} : {1}", k, myCol->Item[ k ] );
}
Console::WriteLine();
}
/*
This code produces the following output.
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
*/
import System.*;
import System.Collections.*;
public class ShortStringDictionary extends DictionaryBase
{
/** @property
*/
public String get_Value(String key)
{
return((String)(get_Dictionary().get_Item(key)));
} //get_Value
/** @property
*/
public void set_Value(String key,String value)
{
get_Dictionary().set_Item(key, value);
} //set_Value
/** @property
*/
public ICollection get_Keys()
{
return get_Dictionary().get_Keys();
} //get_Keys
/** @property
*/
public ICollection get_Values()
{
return get_Dictionary().get_Values();
} //get_Values
public void Add(String key, String value)
{
get_Dictionary().Add(key, value);
} //Add
public boolean Contains(String key)
{
return get_Dictionary().Contains(key);
} //Contains
public void Remove(String key)
{
get_Dictionary().Remove(key);
} //Remove
protected void OnInsert(Object key, Object value)
{
if (!key.GetType().Equals(Type.GetType("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().Equals(Type.GetType("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");
}
}
} //OnInsert
protected void OnRemove(Object key, Object value)
{
if (!key.GetType().Equals(Type.GetType("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");
}
}
} //OnRemove
protected void OnSet(Object key, Object oldValue, Object newValue)
{
if (!key.GetType().Equals(Type.GetType("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().Equals(Type.GetType("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") ;
}
}
} //OnSet
protected void OnValidate(Object key, Object value)
{
if (!key.GetType().Equals(Type.GetType("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().Equals(Type.GetType("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") ;
}
}
} //OnValidate
} //ShortStringDictionary
public class SamplesDictionaryBase
{
public static void main(String[] args)
{
// 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 while. This is the
// preferred method.
Console.WriteLine("Contents of the collection (using for):");
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.
boolean b = mySSC.Contains("Three");
Console.Write("Contains \"Three\": ");
Console.WriteLine(b);
b = mySSC.Contains("Twelve");
Console.Write("Contains \"Twelve\": ");
Console.WriteLine(b);
Console.WriteLine();
// Removes an element from the collection.
mySSC.Remove("Two");
// Displays the contents of the collection.
Console.WriteLine("After removing \"Two\":");
PrintKeysAndValues1(mySSC);
}//main
// Uses the for statement which hides the complexity of the enumerator.
// NOTE: The for statement is the preferred way of enumerating the
// contents of a collection.
public static void PrintKeysAndValues1(ShortStringDictionary myCol)
{
String strValue;
String strKeys[] = new String[myCol.get_Count()];
myCol.get_Keys().CopyTo(strKeys,0);
for (int iCtr = 0; iCtr < myCol.get_Count(); iCtr++){
strValue = myCol.get_Value(strKeys[iCtr]);
Console.WriteLine(" {0,-5} : {1}", strKeys[iCtr], strValue);
}
Console.WriteLine();
} //PrintKeysAndValues1
// Uses the enumerator.
// NOTE: The for 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.get_Current() != null ) {
myDE =((DictionaryEntry)(myEnumerator.get_Current()));
Console.WriteLine(" {0,-5} : {1}", myDE.get_Key(),
myDE.get_Value());
}
}
Console.WriteLine();
} //PrintKeysAndValues2
// Uses the Keys property and the Value property.
public static void PrintKeysAndValues3(ShortStringDictionary myCol)
{
ICollection myKeys = myCol.get_Keys();
IEnumerator myEnumerator = myKeys.GetEnumerator();
while (myEnumerator.MoveNext()) {
String k = myEnumerator.get_Current().ToString();
Console.WriteLine(" {0,-5} : {1}", k, myCol.get_Item(k));
}
Console.WriteLine();
} //PrintKeysAndValues3
} //SamplesDictionaryBase
/*
This code produces the following output.
Contents of the collection (using while):
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
*/
Plattformen
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
.NET Framework unterstützt nicht alle Versionen sämtlicher Plattformen. Eine Liste der unterstützten Versionen finden Sie unter Systemanforderungen.
Versionsinformationen
.NET Framework
Unterstützt in: 2.0, 1.1, 1.0
Siehe auch
Referenz
DictionaryBase-Klasse
DictionaryBase-Member
System.Collections-Namespace
IDictionaryEnumerator
IEnumerator