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NameObjectCollectionBase.BaseClear Method
.NET Framework 1.1
Removes all entries from the NameObjectCollectionBase instance.
[Visual Basic] Protected Sub BaseClear() [C#] protected void BaseClear(); [C++] protected: void BaseClear(); [JScript] protected function BaseClear();
Exceptions
| Exception Type | Condition |
|---|---|
| NotSupportedException | The collection is read-only. |
Remarks
Count is set to zero.
Example
[Visual Basic, C#, C++] The following code example uses BaseClear to remove all elements from a NameObjectCollectionBase.
[Visual Basic] Imports System 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 'New ' Clears all the elements in the collection. Public Sub Clear() Me.BaseClear() End Sub 'Clear End Class 'MyCollection 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 'Main 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 'PrintKeysAndValues End Class 'SamplesNameObjectCollectionBase '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): [C#] 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): */ [C++] #using <mscorlib.dll> #using <system.dll> using namespace System; using namespace System::Collections; using namespace System::Collections::Specialized; public __gc class MyCollection : public NameObjectCollectionBase { private: DictionaryEntry _de; public: // Gets a key-and-value pair (DictionaryEntry) using an index. __property DictionaryEntry get_Item( 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 = __try_cast<DictionaryEntry*>(myEnum->Current); this->BaseAdd(__try_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(S"[{0}] : {1}, {2}", __box(i), myCol->Item[i].Key, myCol->Item[i].Value); } } int main() { // Creates and initializes a new MyCollection instance. IDictionary* d = new ListDictionary(); d->Add(S"red", S"apple"); d->Add(S"yellow", S"banana"); d->Add(S"green", S"pear"); MyCollection* myCol = new MyCollection(d); Console::WriteLine(S"Initial state of the collection (Count = {0}):", __box(myCol->Count)); PrintKeysAndValues(myCol); // Removes all elements from the collection. myCol->Clear(); Console::WriteLine(S"After clearing the collection (Count = {0}):", __box(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): */
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Requirements
Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework
See Also
NameObjectCollectionBase Class | NameObjectCollectionBase Members | System.Collections.Specialized Namespace
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