NameObjectCollectionBase.BaseClear Método
Importante
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Elimina todas las entradas de la instancia NameObjectCollectionBase.
protected:
void BaseClear();
protected void BaseClear ();
member this.BaseClear : unit -> unit
Protected Sub BaseClear ()
La colección es de solo lectura.
En el ejemplo de código siguiente se usa BaseClear para quitar todos los elementos de .NameObjectCollectionBase
#using <system.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
public ref class MyCollection: public NameObjectCollectionBase
{
private:
DictionaryEntry _de;
public:
property DictionaryEntry Item [ int ]
{
// Gets a key-and-value pair (DictionaryEntry) using an index.
DictionaryEntry get( int index )
{
_de.Key = this->BaseGetKey( index );
_de.Value = this->BaseGet( index );
return (_de);
}
}
// Adds elements from an IDictionary* into the new collection.
MyCollection( IDictionary^ d )
{
IEnumerator^ myEnum = d->GetEnumerator();
while ( myEnum->MoveNext() )
{
DictionaryEntry^ de = safe_cast<DictionaryEntry^>(myEnum->Current);
this->BaseAdd( safe_cast<String^>(de->Key), de->Value );
}
}
// Clears all the elements in the collection.
void Clear()
{
this->BaseClear();
}
};
static void PrintKeysAndValues( MyCollection^ myCol )
{
for ( int i = 0; i < myCol->Count; i++ )
{
Console::WriteLine( "[{0}] : {1}, {2}", i, myCol->Item[ i ].Key, myCol->Item[ i ].Value );
}
}
int main()
{
// Creates and initializes a new MyCollection instance.
IDictionary^ d = gcnew ListDictionary;
d->Add( "red", "apple" );
d->Add( "yellow", "banana" );
d->Add( "green", "pear" );
MyCollection^ myCol = gcnew MyCollection( d );
Console::WriteLine( "Initial state of the collection (Count = {0}):", myCol->Count );
PrintKeysAndValues( myCol );
// Removes all elements from the collection.
myCol->Clear();
Console::WriteLine( "After clearing the collection (Count = {0}):", myCol->Count );
PrintKeysAndValues( myCol );
}
/*
This code produces the following output.
Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
After clearing the collection (Count = 0):
*/
using System;
using System.Collections;
using System.Collections.Specialized;
public class MyCollection : NameObjectCollectionBase {
private DictionaryEntry _de = new DictionaryEntry();
// Gets a key-and-value pair (DictionaryEntry) using an index.
public DictionaryEntry this[ int index ] {
get {
_de.Key = this.BaseGetKey( index );
_de.Value = this.BaseGet( index );
return( _de );
}
}
// Adds elements from an IDictionary into the new collection.
public MyCollection( IDictionary d ) {
foreach ( DictionaryEntry de in d ) {
this.BaseAdd( (String) de.Key, de.Value );
}
}
// 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 instance.
IDictionary d = new ListDictionary();
d.Add( "red", "apple" );
d.Add( "yellow", "banana" );
d.Add( "green", "pear" );
MyCollection myCol = new MyCollection( d );
Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
// Removes all elements from the collection.
myCol.Clear();
Console.WriteLine( "After clearing the collection (Count = {0}):", myCol.Count );
PrintKeysAndValues( myCol );
}
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 );
}
}
}
/*
This code produces the following output.
Initial state of the collection (Count = 3):
[0] : red, apple
[1] : yellow, banana
[2] : green, pear
After clearing the collection (Count = 0):
*/
Imports System.Collections
Imports System.Collections.Specialized
Public Class MyCollection
Inherits NameObjectCollectionBase
Private _de As New DictionaryEntry()
' Gets a key-and-value pair (DictionaryEntry) using an index.
Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
Get
_de.Key = Me.BaseGetKey(index)
_de.Value = Me.BaseGet(index)
Return _de
End Get
End Property
' Adds elements from an IDictionary into the new collection.
Public Sub New(d As IDictionary)
Dim de As DictionaryEntry
For Each de In d
Me.BaseAdd(CType(de.Key, [String]), de.Value)
Next de
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 instance.
Dim d = New ListDictionary()
d.Add("red", "apple")
d.Add("yellow", "banana")
d.Add("green", "pear")
Dim myCol As New MyCollection(d)
Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
' Removes all elements from the collection.
myCol.Clear()
Console.WriteLine("After clearing the collection (Count = {0}):", myCol.Count)
PrintKeysAndValues(myCol)
End Sub
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
End Class
'This code produces the following output.
'
'Initial state of the collection (Count = 3):
'[0] : red, apple
'[1] : yellow, banana
'[2] : green, pear
'After clearing the collection (Count = 0):
Count se establece en cero y también se liberan las referencias a otros objetos de los elementos de la colección.
Este método es una operación O(1).
Producto | Versiones |
---|---|
.NET | Core 1.0, Core 1.1, Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
.NET Framework | 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
.NET Standard | 2.0, 2.1 |
UWP | 10.0 |
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