Collection<T>.Count プロパティ
定義
Collection<T> に実際に含まれる要素の数を取得します。Gets the number of elements actually contained in the Collection<T>.
public:
property int Count { int get(); };
public int Count { get; }
member this.Count : int
Public ReadOnly Property Count As Integer
プロパティ値
Collection<T> に実際に格納されている要素の数。The number of elements actually contained in the Collection<T>.
実装
例
次のコード例は、のCollection<T>プロパティとメソッドの多くを示しています。The following code example demonstrates many of the properties and methods of Collection<T>. このコード例では、文字列のコレクションを作成Addし、メソッドを使用して複数Countの文字列を追加し、を表示して、文字列を一覧表示します。The code example creates a collection of strings, uses the Add method to add several strings, displays the Count, and lists the strings. この例ではIndexOf 、メソッドを使用して文字列のインデックスをContains検索し、メソッドを使用して文字列がコレクション内に存在するかどうかを確認します。The example uses the IndexOf method to find the index of a string and the Contains method to determine whether a string is in the collection. この例では、 Insertメソッドを使用して文字列を挿入し、既定Item[Int32]のプロパティ (のC#インデクサー) を使用して文字列を取得して設定します。The example inserts a string using the Insert method and retrieves and sets strings using the default Item[Int32] property (the indexer in C#). この例では、メソッドとインデックスRemove RemoveAtを使用して、メソッドを使用して文字列 id によって文字列を削除します。The example removes strings by string identity using the Remove method and by index using the RemoveAt method. 最後に、 Clearメソッドを使用して、コレクションからすべての文字列をクリアします。Finally, the Clear method is used to clear all strings from the collection.
using namespace System;
using namespace System::Collections::Generic;
using namespace System::Collections::ObjectModel;
public ref class Demo
{
public:
static void Main()
{
Collection<String^>^ dinosaurs = gcnew Collection<String^>();
dinosaurs->Add("Psitticosaurus");
dinosaurs->Add("Caudipteryx");
dinosaurs->Add("Compsognathus");
dinosaurs->Add("Muttaburrasaurus");
Console::WriteLine("{0} dinosaurs:", dinosaurs->Count);
Display(dinosaurs);
Console::WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}",
dinosaurs->IndexOf("Muttaburrasaurus"));
Console::WriteLine("\nContains(\"Caudipteryx\"): {0}",
dinosaurs->Contains("Caudipteryx"));
Console::WriteLine("\nInsert(2, \"Nanotyrannus\")");
dinosaurs->Insert(2, "Nanotyrannus");
Display(dinosaurs);
Console::WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);
Console::WriteLine("\ndinosaurs[2] = \"Microraptor\"");
dinosaurs[2] = "Microraptor";
Display(dinosaurs);
Console::WriteLine("\nRemove(\"Microraptor\")");
dinosaurs->Remove("Microraptor");
Display(dinosaurs);
Console::WriteLine("\nRemoveAt(0)");
dinosaurs->RemoveAt(0);
Display(dinosaurs);
Console::WriteLine("\ndinosaurs.Clear()");
dinosaurs->Clear();
Console::WriteLine("Count: {0}", dinosaurs->Count);
}
private:
static void Display(Collection<String^>^ cs)
{
Console::WriteLine();
for each( String^ item in cs )
{
Console::WriteLine(item);
}
}
};
int main()
{
Demo::Main();
}
/* This code example produces the following output:
4 dinosaurs:
Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus
IndexOf("Muttaburrasaurus"): 3
Contains("Caudipteryx"): True
Insert(2, "Nanotyrannus")
Psitticosaurus
Caudipteryx
Nanotyrannus
Compsognathus
Muttaburrasaurus
dinosaurs[2]: Nanotyrannus
dinosaurs[2] = "Microraptor"
Psitticosaurus
Caudipteryx
Microraptor
Compsognathus
Muttaburrasaurus
Remove("Microraptor")
Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus
RemoveAt(0)
Caudipteryx
Compsognathus
Muttaburrasaurus
dinosaurs.Clear()
Count: 0
*/
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
public class Demo
{
public static void Main()
{
Collection<string> dinosaurs = new Collection<string>();
dinosaurs.Add("Psitticosaurus");
dinosaurs.Add("Caudipteryx");
dinosaurs.Add("Compsognathus");
dinosaurs.Add("Muttaburrasaurus");
Console.WriteLine("{0} dinosaurs:", dinosaurs.Count);
Display(dinosaurs);
Console.WriteLine("\nIndexOf(\"Muttaburrasaurus\"): {0}",
dinosaurs.IndexOf("Muttaburrasaurus"));
Console.WriteLine("\nContains(\"Caudipteryx\"): {0}",
dinosaurs.Contains("Caudipteryx"));
Console.WriteLine("\nInsert(2, \"Nanotyrannus\")");
dinosaurs.Insert(2, "Nanotyrannus");
Display(dinosaurs);
Console.WriteLine("\ndinosaurs[2]: {0}", dinosaurs[2]);
Console.WriteLine("\ndinosaurs[2] = \"Microraptor\"");
dinosaurs[2] = "Microraptor";
Display(dinosaurs);
Console.WriteLine("\nRemove(\"Microraptor\")");
dinosaurs.Remove("Microraptor");
Display(dinosaurs);
Console.WriteLine("\nRemoveAt(0)");
dinosaurs.RemoveAt(0);
Display(dinosaurs);
Console.WriteLine("\ndinosaurs.Clear()");
dinosaurs.Clear();
Console.WriteLine("Count: {0}", dinosaurs.Count);
}
private static void Display(Collection<string> cs)
{
Console.WriteLine();
foreach( string item in cs )
{
Console.WriteLine(item);
}
}
}
/* This code example produces the following output:
4 dinosaurs:
Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus
IndexOf("Muttaburrasaurus"): 3
Contains("Caudipteryx"): True
Insert(2, "Nanotyrannus")
Psitticosaurus
Caudipteryx
Nanotyrannus
Compsognathus
Muttaburrasaurus
dinosaurs[2]: Nanotyrannus
dinosaurs[2] = "Microraptor"
Psitticosaurus
Caudipteryx
Microraptor
Compsognathus
Muttaburrasaurus
Remove("Microraptor")
Psitticosaurus
Caudipteryx
Compsognathus
Muttaburrasaurus
RemoveAt(0)
Caudipteryx
Compsognathus
Muttaburrasaurus
dinosaurs.Clear()
Count: 0
*/
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Public Class Demo
Public Shared Sub Main()
Dim dinosaurs As New Collection(Of String)
dinosaurs.Add("Psitticosaurus")
dinosaurs.Add("Caudipteryx")
dinosaurs.Add("Compsognathus")
dinosaurs.Add("Muttaburrasaurus")
Console.WriteLine("{0} dinosaurs:", dinosaurs.Count)
Display(dinosaurs)
Console.WriteLine(vbLf & "IndexOf(""Muttaburrasaurus""): {0}", _
dinosaurs.IndexOf("Muttaburrasaurus"))
Console.WriteLine(vbLf & "Contains(""Caudipteryx""): {0}", _
dinosaurs.Contains("Caudipteryx"))
Console.WriteLine(vbLf & "Insert(2, ""Nanotyrannus"")")
dinosaurs.Insert(2, "Nanotyrannus")
Display(dinosaurs)
Console.WriteLine(vbLf & "dinosaurs(2): {0}", dinosaurs(2))
Console.WriteLine(vbLf & "dinosaurs(2) = ""Microraptor""")
dinosaurs(2) = "Microraptor"
Display(dinosaurs)
Console.WriteLine(vbLf & "Remove(""Microraptor"")")
dinosaurs.Remove("Microraptor")
Display(dinosaurs)
Console.WriteLine(vbLf & "RemoveAt(0)")
dinosaurs.RemoveAt(0)
Display(dinosaurs)
Console.WriteLine(vbLf & "dinosaurs.Clear()")
dinosaurs.Clear()
Console.WriteLine("Count: {0}", dinosaurs.Count)
End Sub
Private Shared Sub Display(ByVal cs As Collection(Of String))
Console.WriteLine()
For Each item As String In cs
Console.WriteLine(item)
Next item
End Sub
End Class
' This code example produces the following output:
'
'4 dinosaurs:
'
'Psitticosaurus
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'IndexOf("Muttaburrasaurus"): 3
'
'Contains("Caudipteryx"): True
'
'Insert(2, "Nanotyrannus")
'
'Psitticosaurus
'Caudipteryx
'Nanotyrannus
'Compsognathus
'Muttaburrasaurus
'
'dinosaurs(2): Nanotyrannus
'
'dinosaurs(2) = "Microraptor"
'
'Psitticosaurus
'Caudipteryx
'Microraptor
'Compsognathus
'Muttaburrasaurus
'
'Remove("Microraptor")
'
'Psitticosaurus
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'RemoveAt(0)
'
'Caudipteryx
'Compsognathus
'Muttaburrasaurus
'
'dinosaurs.Clear()
'Count: 0
注釈
このプロパティ値を取得することは、O(1) 操作になります。Retrieving the value of this property is an O(1) operation.