HybridDictionary.IEnumerable.GetEnumerator Metode
Definisi
Penting
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Mengembalikan IEnumerator yang berulang melalui HybridDictionary.
virtual System::Collections::IEnumerator ^ System.Collections.IEnumerable.GetEnumerator() = System::Collections::IEnumerable::GetEnumerator;System.Collections.IEnumerator IEnumerable.GetEnumerator ();abstract member System.Collections.IEnumerable.GetEnumerator : unit -> System.Collections.IEnumerator
override this.System.Collections.IEnumerable.GetEnumerator : unit -> System.Collections.IEnumeratorFunction GetEnumerator () As IEnumerator Implements IEnumerable.GetEnumeratorMengembalikan
Untuk IEnumeratorHybridDictionary.
Penerapan
Contoh
Contoh kode berikut menghitung elemen dari HybridDictionary.
#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues1( IDictionary^ myCol );
void PrintKeysAndValues2( IDictionary^ myCol );
void PrintKeysAndValues3( HybridDictionary^ myCol );
int main()
{
// Creates and initializes a new HybridDictionary.
HybridDictionary^ myCol = gcnew HybridDictionary;
myCol->Add( "Braeburn Apples", "1.49" );
myCol->Add( "Fuji Apples", "1.29" );
myCol->Add( "Gala Apples", "1.49" );
myCol->Add( "Golden Delicious Apples", "1.29" );
myCol->Add( "Granny Smith Apples", "0.89" );
myCol->Add( "Red Delicious Apples", "0.99" );
myCol->Add( "Plantain Bananas", "1.49" );
myCol->Add( "Yellow Bananas", "0.79" );
myCol->Add( "Strawberries", "3.33" );
myCol->Add( "Cranberries", "5.98" );
myCol->Add( "Navel Oranges", "1.29" );
myCol->Add( "Grapes", "1.99" );
myCol->Add( "Honeydew Melon", "0.59" );
myCol->Add( "Seedless Watermelon", "0.49" );
myCol->Add( "Pineapple", "1.49" );
myCol->Add( "Nectarine", "1.99" );
myCol->Add( "Plums", "1.69" );
myCol->Add( "Peaches", "1.99" );
// 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 IDictionaryEnumerator:" );
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 );
}
// 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.
void PrintKeysAndValues1( IDictionary^ myCol ) {
Console::WriteLine( " KEY VALUE" );
for each ( DictionaryEntry^ de in myCol )
Console::WriteLine( " {0,-25} {1}", de->Key, de->Value );
Console::WriteLine();
}
// Uses the enumerator.
void PrintKeysAndValues2( IDictionary^ myCol )
{
IDictionaryEnumerator^ myEnumerator = myCol->GetEnumerator();
Console::WriteLine( " KEY VALUE" );
while ( myEnumerator->MoveNext() )
Console::WriteLine( " {0,-25} {1}", myEnumerator->Key, myEnumerator->Value );
Console::WriteLine();
}
// Uses the Keys, Values, Count, and Item properties.
void PrintKeysAndValues3( HybridDictionary^ 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 output similar to the following:
Displays the elements using for each:
KEY VALUE
Seedless Watermelon 0.49
Nectarine 1.99
Cranberries 5.98
Plantain Bananas 1.49
Honeydew Melon 0.59
Pineapple 1.49
Strawberries 3.33
Grapes 1.99
Braeburn Apples 1.49
Peaches 1.99
Red Delicious Apples 0.99
Golden Delicious Apples 1.29
Yellow Bananas 0.79
Granny Smith Apples 0.89
Gala Apples 1.49
Plums 1.69
Navel Oranges 1.29
Fuji Apples 1.29
Displays the elements using the IDictionaryEnumerator:
KEY VALUE
Seedless Watermelon 0.49
Nectarine 1.99
Cranberries 5.98
Plantain Bananas 1.49
Honeydew Melon 0.59
Pineapple 1.49
Strawberries 3.33
Grapes 1.99
Braeburn Apples 1.49
Peaches 1.99
Red Delicious Apples 0.99
Golden Delicious Apples 1.29
Yellow Bananas 0.79
Granny Smith Apples 0.89
Gala Apples 1.49
Plums 1.69
Navel Oranges 1.29
Fuji Apples 1.29
Displays the elements using the Keys, Values, Count, and Item properties:
INDEX KEY VALUE
0 Seedless Watermelon 0.49
1 Nectarine 1.99
2 Cranberries 5.98
3 Plantain Bananas 1.49
4 Honeydew Melon 0.59
5 Pineapple 1.49
6 Strawberries 3.33
7 Grapes 1.99
8 Braeburn Apples 1.49
9 Peaches 1.99
10 Red Delicious Apples 0.99
11 Golden Delicious Apples 1.29
12 Yellow Bananas 0.79
13 Granny Smith Apples 0.89
14 Gala Apples 1.49
15 Plums 1.69
16 Navel Oranges 1.29
17 Fuji Apples 1.29
*/
using System;
using System.Collections;
using System.Collections.Specialized;
public class SamplesHybridDictionary {
public static void Main() {
// Creates and initializes a new HybridDictionary.
HybridDictionary myCol = new HybridDictionary();
myCol.Add( "Braeburn Apples", "1.49" );
myCol.Add( "Fuji Apples", "1.29" );
myCol.Add( "Gala Apples", "1.49" );
myCol.Add( "Golden Delicious Apples", "1.29" );
myCol.Add( "Granny Smith Apples", "0.89" );
myCol.Add( "Red Delicious Apples", "0.99" );
myCol.Add( "Plantain Bananas", "1.49" );
myCol.Add( "Yellow Bananas", "0.79" );
myCol.Add( "Strawberries", "3.33" );
myCol.Add( "Cranberries", "5.98" );
myCol.Add( "Navel Oranges", "1.29" );
myCol.Add( "Grapes", "1.99" );
myCol.Add( "Honeydew Melon", "0.59" );
myCol.Add( "Seedless Watermelon", "0.49" );
myCol.Add( "Pineapple", "1.49" );
myCol.Add( "Nectarine", "1.99" );
myCol.Add( "Plums", "1.69" );
myCol.Add( "Peaches", "1.99" );
// 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 IDictionaryEnumerator:" );
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 );
}
// 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( IDictionary 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( IDictionary myCol ) {
IDictionaryEnumerator myEnumerator = myCol.GetEnumerator();
Console.WriteLine( " KEY VALUE" );
while ( myEnumerator.MoveNext() )
Console.WriteLine( " {0,-25} {1}", myEnumerator.Key, myEnumerator.Value );
Console.WriteLine();
}
// Uses the Keys, Values, Count, and Item properties.
public static void PrintKeysAndValues3( HybridDictionary 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 output similar to the following:
Displays the elements using foreach:
KEY VALUE
Seedless Watermelon 0.49
Nectarine 1.99
Cranberries 5.98
Plantain Bananas 1.49
Honeydew Melon 0.59
Pineapple 1.49
Strawberries 3.33
Grapes 1.99
Braeburn Apples 1.49
Peaches 1.99
Red Delicious Apples 0.99
Golden Delicious Apples 1.29
Yellow Bananas 0.79
Granny Smith Apples 0.89
Gala Apples 1.49
Plums 1.69
Navel Oranges 1.29
Fuji Apples 1.29
Displays the elements using the IDictionaryEnumerator:
KEY VALUE
Seedless Watermelon 0.49
Nectarine 1.99
Cranberries 5.98
Plantain Bananas 1.49
Honeydew Melon 0.59
Pineapple 1.49
Strawberries 3.33
Grapes 1.99
Braeburn Apples 1.49
Peaches 1.99
Red Delicious Apples 0.99
Golden Delicious Apples 1.29
Yellow Bananas 0.79
Granny Smith Apples 0.89
Gala Apples 1.49
Plums 1.69
Navel Oranges 1.29
Fuji Apples 1.29
Displays the elements using the Keys, Values, Count, and Item properties:
INDEX KEY VALUE
0 Seedless Watermelon 0.49
1 Nectarine 1.99
2 Cranberries 5.98
3 Plantain Bananas 1.49
4 Honeydew Melon 0.59
5 Pineapple 1.49
6 Strawberries 3.33
7 Grapes 1.99
8 Braeburn Apples 1.49
9 Peaches 1.99
10 Red Delicious Apples 0.99
11 Golden Delicious Apples 1.29
12 Yellow Bananas 0.79
13 Granny Smith Apples 0.89
14 Gala Apples 1.49
15 Plums 1.69
16 Navel Oranges 1.29
17 Fuji Apples 1.29
*/
Imports System.Collections
Imports System.Collections.Specialized
Public Class SamplesHybridDictionary
Public Shared Sub Main()
' Creates and initializes a new HybridDictionary.
Dim myCol As New HybridDictionary()
myCol.Add("Braeburn Apples", "1.49")
myCol.Add("Fuji Apples", "1.29")
myCol.Add("Gala Apples", "1.49")
myCol.Add("Golden Delicious Apples", "1.29")
myCol.Add("Granny Smith Apples", "0.89")
myCol.Add("Red Delicious Apples", "0.99")
myCol.Add("Plantain Bananas", "1.49")
myCol.Add("Yellow Bananas", "0.79")
myCol.Add("Strawberries", "3.33")
myCol.Add("Cranberries", "5.98")
myCol.Add("Navel Oranges", "1.29")
myCol.Add("Grapes", "1.99")
myCol.Add("Honeydew Melon", "0.59")
myCol.Add("Seedless Watermelon", "0.49")
myCol.Add("Pineapple", "1.49")
myCol.Add("Nectarine", "1.99")
myCol.Add("Plums", "1.69")
myCol.Add("Peaches", "1.99")
' 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 IDictionaryEnumerator:")
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)
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 IDictionary)
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 IDictionary)
Dim myEnumerator As IDictionaryEnumerator = myCol.GetEnumerator()
Console.WriteLine(" KEY VALUE")
While myEnumerator.MoveNext()
Console.WriteLine(" {0,-25} {1}", myEnumerator.Key, myEnumerator.Value)
End While
Console.WriteLine()
End Sub
' Uses the Keys, Values, Count, and Item properties.
Public Shared Sub PrintKeysAndValues3(myCol As HybridDictionary)
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 output similar to the following:
'
'Displays the elements using For Each:
' KEY VALUE
' Seedless Watermelon 0.49
' Nectarine 1.99
' Cranberries 5.98
' Plantain Bananas 1.49
' Honeydew Melon 0.59
' Pineapple 1.49
' Strawberries 3.33
' Grapes 1.99
' Braeburn Apples 1.49
' Peaches 1.99
' Red Delicious Apples 0.99
' Golden Delicious Apples 1.29
' Yellow Bananas 0.79
' Granny Smith Apples 0.89
' Gala Apples 1.49
' Plums 1.69
' Navel Oranges 1.29
' Fuji Apples 1.29
'
'Displays the elements using the IDictionaryEnumerator:
' KEY VALUE
' Seedless Watermelon 0.49
' Nectarine 1.99
' Cranberries 5.98
' Plantain Bananas 1.49
' Honeydew Melon 0.59
' Pineapple 1.49
' Strawberries 3.33
' Grapes 1.99
' Braeburn Apples 1.49
' Peaches 1.99
' Red Delicious Apples 0.99
' Golden Delicious Apples 1.29
' Yellow Bananas 0.79
' Granny Smith Apples 0.89
' Gala Apples 1.49
' Plums 1.69
' Navel Oranges 1.29
' Fuji Apples 1.29
'
'Displays the elements using the Keys, Values, Count, and Item properties:
' INDEX KEY VALUE
' 0 Seedless Watermelon 0.49
' 1 Nectarine 1.99
' 2 Cranberries 5.98
' 3 Plantain Bananas 1.49
' 4 Honeydew Melon 0.59
' 5 Pineapple 1.49
' 6 Strawberries 3.33
' 7 Grapes 1.99
' 8 Braeburn Apples 1.49
' 9 Peaches 1.99
' 10 Red Delicious Apples 0.99
' 11 Golden Delicious Apples 1.29
' 12 Yellow Bananas 0.79
' 13 Granny Smith Apples 0.89
' 14 Gala Apples 1.49
' 15 Plums 1.69
' 16 Navel Oranges 1.29
' 17 Fuji Apples 1.29
Keterangan
Pernyataan foreach bahasa C# (for each dalam Visual Basic) menyembunyikan kompleksitas enumerator. Oleh karena itu, penggunaan foreach disarankan, alih-alih secara langsung memanipulasi enumerator.
Enumerator dapat digunakan untuk membaca data dalam koleksi, tetapi tidak dapat digunakan untuk memodifikasi koleksi yang mendasar.
Awalnya, enumerator diposisikan sebelum elemen pertama dalam koleksi. Reset juga membawa enumerator kembali ke posisi ini. Pada posisi ini, panggilan Current melemparkan pengecualian. Oleh karena itu, Anda harus memanggil MoveNext untuk memajukan enumerator ke elemen pertama koleksi sebelum membaca nilai Current.
Current mengembalikan objek yang sama hingga atau MoveNextReset dipanggil. MoveNextCurrent mengatur ke elemen berikutnya.
Jika MoveNext melewati akhir koleksi, enumerator diposisikan setelah elemen terakhir dalam koleksi dan MoveNext mengembalikan false. Ketika enumerator berada di posisi ini, panggilan berikutnya untuk MoveNext juga mengembalikan false. Jika panggilan terakhir untuk MoveNext dikembalikan false, panggilan Current akan melemparkan pengecualian. Untuk mengatur Current ke elemen pertama koleksi lagi, Anda dapat memanggil Reset diikuti dengan MoveNext.
Enumerator tetap valid selama koleksi tetap tidak berubah. Jika perubahan dilakukan pada koleksi, seperti menambahkan, memodifikasi, atau menghapus elemen, enumerator tidak valid dan panggilan berikutnya ke MoveNext atau Reset melemparkan InvalidOperationException. Jika koleksi dimodifikasi antara MoveNext dan Current, Current mengembalikan elemen yang diatur ke, bahkan jika enumerator sudah tidak valid.
Enumerator tidak memiliki akses eksklusif ke koleksi; oleh karena itu, menghitung melalui koleksi secara intrinsik bukan prosedur aman utas. Bahkan ketika koleksi disinkronkan, utas lain masih dapat memodifikasi koleksi, yang menyebabkan enumerator melemparkan pengecualian. Untuk menjamin keamanan utas selama enumerasi, Anda dapat mengunci koleksi selama seluruh enumerasi atau menangkap pengecualian yang dihasilkan dari perubahan yang dibuat oleh utas lain.
Metode ini adalah operasi O(1).
Berlaku untuk
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