CurrencyManager.Count プロパティとは何？わかりやすく解説 Weblio辞書

.NET Framework クラスライブラリリファレンス

索引トップ用語の索引ランキング

CurrencyManager.Count プロパティ

リスト内の項目数を取得します。

名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文

Visual Basic (宣言)

Public Overrides ReadOnly
 Property Count As Integer

Visual Basic (使用法)

Dim instance As CurrencyManager
Dim value As Integer

value = instance.Count

public override int Count { get;
 }

C++

public:
virtual property int Count {
    int get () override;
}

/** @property */
public int get_Count ()

JScript

public override function get
 Count () : int

プロパティ値
リストの項目数。

解説

Count プロパティを使用すると、リストの末尾に到達したことを判断できます。CurrencyManager は 0 から始まる項目の配列を格納しているため、リストの末尾は常に Count から 1 を引いた値です。

使用例

Count プロパティによって判断されるリストの最終項目に到達するまで、リストを反復処理するコード例を次に示します。

Visual Basic

Private Sub PrintListItems()
    ' Get the CurrencyManager of a TextBox control.
    Dim myCurrencyManager As CurrencyManager
 = CType(textBox1.BindingContext(0), CurrencyManager)
    ' Presuming the list is a DataView, create a DataRowView variable.
    Dim drv As DataRowView
    Dim i As Integer
    For i = 0 To myCurrencyManager.Count -
 1
        myCurrencyManager.Position = i
        drv = CType(myCurrencyManager.Current, DataRowView)
        ' Presuming a column named CompanyName exists.
        Console.WriteLine(drv("CompanyName"))
    Next i
End Sub 'PrintListItems

    private void PrintListItems() {
    // Get the CurrencyManager of a TextBox control.
    CurrencyManager myCurrencyManager = (CurrencyManager)textBox1.BindingContext[0];
    // Presuming the list is a DataView, create a DataRowView variable.
    DataRowView drv;
    for(int i = 0; i < myCurrencyManager.Count;
 i++) {
        myCurrencyManager.Position = i;
        drv = (DataRowView)myCurrencyManager.Current;
        // Presuming a column named CompanyName exists.
        Console.WriteLine(drv["CompanyName"]);
    }
}

C++

void PrintListItems()
{
   
   // Get the CurrencyManager of a TextBox control.
   CurrencyManager^ myCurrencyManager = dynamic_cast<CurrencyManager^>(textBox1->BindingContext[nullptr]);
   
   // Presuming the list is a DataView, create a DataRowView variable.
   DataRowView^ drv;
   for ( int i = 0; i < myCurrencyManager->Count;
 i++ )
   {
      myCurrencyManager->Position = i;
      drv = dynamic_cast<DataRowView^>(myCurrencyManager->Current);
      
      // Presuming a column named CompanyName exists.
      Console::WriteLine( drv[ "CompanyName" ] );

   }
}

private void PrintListItems()
{
    // Get the CurrencyManager of a TextBox control.
    CurrencyManager myCurrencyManager = ((CurrencyManager)(
        textBox1.get_BindingContext().get_Item((System.Int32)(0))));

    // Presuming the list is a DataView, create a DataRowView variable.
    DataRowView drv;
    for (int i = 0; i < myCurrencyManager.get_Count();
 i++) {
        myCurrencyManager.set_Position(i);
        drv = (DataRowView)(myCurrencyManager.get_Current());
        // Presuming a column named CompanyName exists.
        Console.WriteLine(drv.get_Item("CompanyName"));
    }
} //PrintListItems

JScript

    private function PrintListItems() {
    // Get the CurrencyManager of a TextBox control.
    var myCurrencyManager : CurrencyManager = CurrencyManager(textBox1.BindingContext[0]);
    // Presuming the list is a DataView, create a DataRowView variable.
    var drv : DataRowView;
    for(var i : int = 0;
 i < myCurrencyManager.Count; i++) {
        myCurrencyManager.Position = i;
        drv = DataRowView(myCurrencyManager.Current);
        // Presuming a column named CompanyName exists.
        Console.WriteLine(drv["CompanyName"]);
    }
}