.NET Framework Class Library
StringCollection.Clear Method
Removes all the strings from the StringCollection.
Assembly: System (in System.dll)
Syntax
Visual Basic
Public Sub Clear
C#
public void Clear()
Visual C++
public: virtual void Clear() sealed
F#
abstract Clear : unit -> unit override Clear : unit -> unit
Implements
IList.Clear()Remarks
Count is set to zero, and references to other objects from elements of the collection are also released.
This method is an O(n) operation, where n is Count.
Examples
The following code example removes elements from the StringCollection.
Visual Basic
Imports System Imports System.Collections Imports System.Collections.Specialized Public Class SamplesStringCollection Public Shared Sub Main() ' Creates and initializes a new StringCollection. Dim myCol As New StringCollection() Dim myArr() As [String] = {"RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED"} myCol.AddRange(myArr) Console.WriteLine("Initial contents of the StringCollection:") PrintValues(myCol) ' Removes one element from the StringCollection. myCol.Remove("yellow") Console.WriteLine("After removing ""yellow"":") PrintValues(myCol) ' Removes all occurrences of a value from the StringCollection. Dim i As Integer = myCol.IndexOf("RED") While i > - 1 myCol.RemoveAt(i) i = myCol.IndexOf("RED") End While Console.WriteLine("After removing all occurrences of ""RED"":") PrintValues(myCol) ' Clears the entire collection. myCol.Clear() Console.WriteLine("After clearing the collection:") PrintValues(myCol) End Sub 'Main Public Shared Sub PrintValues(myCol As IEnumerable) Dim obj As [Object] For Each obj In myCol Console.WriteLine(" {0}", obj) Next obj Console.WriteLine() End Sub 'PrintValues End Class 'SamplesStringCollection 'This code produces the following output. ' 'Initial contents of the StringCollection: ' RED ' orange ' yellow ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' 'After removing "yellow": ' RED ' orange ' RED ' green ' blue ' RED ' indigo ' violet ' RED ' 'After removing all occurrences of "RED": ' orange ' green ' blue ' indigo ' violet ' 'After clearing the collection: '
C#
using System; using System.Collections; using System.Collections.Specialized; public class SamplesStringCollection { public static void Main() { // Creates and initializes a new StringCollection. StringCollection myCol = new StringCollection(); String[] myArr = new String[] { "RED", "orange", "yellow", "RED", "green", "blue", "RED", "indigo", "violet", "RED" }; myCol.AddRange( myArr ); Console.WriteLine( "Initial contents of the StringCollection:" ); PrintValues( myCol ); // Removes one element from the StringCollection. myCol.Remove( "yellow" ); Console.WriteLine( "After removing \"yellow\":" ); PrintValues( myCol ); // Removes all occurrences of a value from the StringCollection. int i = myCol.IndexOf( "RED" ); while ( i > -1 ) { myCol.RemoveAt( i ); i = myCol.IndexOf( "RED" ); } Console.WriteLine( "After removing all occurrences of \"RED\":" ); PrintValues( myCol ); // Clears the entire collection. myCol.Clear(); Console.WriteLine( "After clearing the collection:" ); PrintValues( myCol ); } public static void PrintValues( IEnumerable myCol ) { foreach ( Object obj in myCol ) Console.WriteLine( " {0}", obj ); Console.WriteLine(); } } /* This code produces the following output. Initial contents of the StringCollection: RED orange yellow RED green blue RED indigo violet RED After removing "yellow": RED orange RED green blue RED indigo violet RED After removing all occurrences of "RED": orange green blue indigo violet After clearing the collection: */
Visual C++
#using <System.dll> using namespace System; using namespace System::Collections; using namespace System::Collections::Specialized; void PrintValues( IEnumerable^ myCol ); int main() { // Creates and initializes a new StringCollection. StringCollection^ myCol = gcnew StringCollection; array<String^>^myArr = {"RED","orange","yellow","RED","green","blue","RED","indigo","violet","RED"}; myCol->AddRange( myArr ); Console::WriteLine( "Initial contents of the StringCollection:" ); PrintValues( myCol ); // Removes one element from the StringCollection. myCol->Remove( "yellow" ); Console::WriteLine( "After removing \"yellow\":" ); PrintValues( myCol ); // Removes all occurrences of a value from the StringCollection. int i = myCol->IndexOf( "RED" ); while ( i > -1 ) { myCol->RemoveAt( i ); i = myCol->IndexOf( "RED" ); } Console::WriteLine( "After removing all occurrences of \"RED\":" ); PrintValues( myCol ); // Clears the entire collection. myCol->Clear(); Console::WriteLine( "After clearing the collection:" ); PrintValues( myCol ); } void PrintValues( IEnumerable^ myCol ) { IEnumerator^ myEnum = myCol->GetEnumerator(); while ( myEnum->MoveNext() ) { Object^ obj = safe_cast<Object^>(myEnum->Current); Console::WriteLine( " {0}", obj ); } Console::WriteLine(); } /* This code produces the following output. Initial contents of the StringCollection: RED orange yellow RED green blue RED indigo violet RED After removing "yellow": RED orange RED green blue RED indigo violet RED After removing all occurrences of "RED": orange green blue indigo violet After clearing the collection: */
Version Information
.NET Framework
Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0.NET Framework Client Profile
Supported in: 4, 3.5 SP1Platforms
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
See Also