すべての文字列を StringCollection から削除します。
名前空間: System.Collections.Specialized
アセンブリ: System (system.dll 内)
構文
'宣言
Public Sub Clear
'使用
Dim instance As StringCollection
instance.Clear
public void Clear ()
public:
virtual void Clear () sealed
public final void Clear ()
public final function Clear ()
解説
Count はゼロに設定され、コレクションの要素からの他のオブジェクトへの参照も解放されます。
このメソッドは O(n) 操作です。ここで、n は Count です。
使用例
StringCollection から要素を削除する例を次に示します。
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:
'
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:
*/
#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:
*/
import System.* ;
import System.Collections.* ;
import System.Collections.Specialized.* ;
public class SamplesStringCollection
{
public static void main(String[] args)
{
// 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);
} //main
public static void PrintValues(IEnumerable myCol)
{
Object obj = null;
IEnumerator objEnum = myCol.GetEnumerator();
while (objEnum.MoveNext()) {
obj = objEnum.get_Current();
Console.WriteLine(" {0}", obj);
}
Console.WriteLine();
} //PrintValues
} //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:
*/
プラットフォーム
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
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。
バージョン情報
.NET Framework
サポート対象 : 2.0、1.1、1.0
参照
関連項目
StringCollection クラス
StringCollection メンバ
System.Collections.Specialized 名前空間
Count