BindingsCollection クラスとは何？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

BindingsCollection クラス

コントロールの Binding オブジェクトのコレクションを表します。

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 Class BindingsCollection
    Inherits BaseCollection

Visual Basic (使用法)

Dim instance As BindingsCollection

public class BindingsCollection : BaseCollection

C++

public ref class BindingsCollection : public
 BaseCollection

public class BindingsCollection extends BaseCollection

JScript

public class BindingsCollection extends
 BaseCollection

解説

単純なデータ連結は、Binding オブジェクトを BindingsCollection に追加することによって実行されます。Control クラスから継承される任意のオブジェクトは、DataBindings プロパティを使用して BindingsCollection にアクセスできます。データ連結をサポートする Windows コントロールの一覧については、Binding クラスのトピックを参照してください。

使用例

TextBox コントロールの Text プロパティをデータベース内のフィールドにバインドする例を次に示します。

Visual Basic

Private Sub BindTextBoxControl()
   Dim myDataSet As New
 DataSet()
   ' Insert code to populate the DataSet with tables, columns, and data.

   ' Creates a new Binding object. 
   Dim myBinding As New
 Binding("Text", myDataSet, _
   "customers.custToOrders.OrderAmount")
   
   ' Adds event delegates for the Parse and Format events.
   AddHandler myBinding.Parse, AddressOf CurrencyToDecimal
   AddHandler myBinding.Format, AddressOf DecimalToCurrency
     
   ' Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding)
End Sub 
    
Private Sub DecimalToCurrency(sender As
 Object, _
   cevent As ConvertEventArgs)
   ' This method is the Format event handler. Whenever the
   ' control displays a new value, the value is converted from
   ' its native Decimal type to a string. The ToString method
   ' then formats the value as a Currency, by using the
   ' formatting character "c". 
   cevent.Value = CDec(cevent.Value).ToString("c")
End Sub 
    
Private Sub CurrencyToDecimal(sender As
 Object, _
cevent As ConvertEventArgs)
   ' This method is the Parse event handler. The Parse event
   ' occurs whenever the displayed value changes. The static
   ' Parse method of the Decimal structure converts the 
   ' string back to its native Decimal type. 
   cevent.Value = Decimal.Parse(cevent.Value.ToString(), _
   NumberStyles.Currency, nothing)
   End Sub

private void BindTextBoxControl()
{
   DataSet myDataSet = new DataSet();
   /* Insert code to populate the DataSet with tables, 
   columns, and data. */

   // Creates a new Binding object. 
   Binding myBinding = new Binding
   ("Text", myDataSet, "customers.custToOrders.OrderAmount");

   // Adds event delegates for the Parse and Format events.
   myBinding.Parse += new ConvertEventHandler(CurrencyToDecimal);
   myBinding.Format += new ConvertEventHandler(DecimalToCurrency);

   // Adds the new Binding to the BindingsCollection.
   text1.DataBindings.Add(myBinding);
}

private void DecimalToCurrency(object sender,
 
   ConvertEventArgs cevent)
{
   /* This method is the Format event handler. Whenever the 
   control displays a new value, the value is converted from 
   its native Decimal type to a string. The ToString method 
   then formats the value as a Currency, by using the 
   formatting character "c". */
   cevent.Value = ((decimal) cevent.Value).ToString("c");
}

private void CurrencyToDecimal(object sender,
 
   ConvertEventArgs cevent)
{   
   /* This method is the Parse event handler. The Parse event 
   occurs whenever the displayed value changes. The static 
   Parse method of the Decimal structure converts the 
   string back to its native Decimal type. */
   cevent.Value = Decimal.Parse(cevent.Value.ToString(),
   NumberStyles.Currency, null);
}

C++

private:
   void BindTextBoxControl()
   {
      DataSet^ myDataSet = gcnew DataSet;
      /* Insert code to populate the DataSet with tables, 
      columns, and data. */

      // Creates a new Binding object. 
      Binding^ myBinding = gcnew Binding(
         "Text",myDataSet,"customers.custToOrders.OrderAmount"
 );
      
      // Adds event delegates for the Parse and Format events.
      myBinding->Parse += gcnew ConvertEventHandler( this,
 &Form1::CurrencyToDecimal );
      myBinding->Format += gcnew ConvertEventHandler( this,
 &Form1::DecimalToCurrency );
      
      // Adds the new Binding to the BindingsCollection.
      text1->DataBindings->Add( myBinding );
   }

   void DecimalToCurrency( Object^ /*sender*/, ConvertEventArgs^
 cevent )
   {
      /* This method is the Format event handler. Whenever the 
      control displays a new value, the value is converted from
 
      its native Decimal type to a string. The ToString method
 
      then formats the value as a Currency, by using the 
      formatting character "c". */
      cevent->Value = safe_cast<Decimal ^>(cevent->Value)->ToString(
  "c" );
   }

   void CurrencyToDecimal( Object^ /*sender*/, ConvertEventArgs^
 cevent )
   {
      /* This method is the Parse event handler. The Parse event 
      occurs whenever the displayed value changes. The static
 
      Parse method of the Decimal structure converts the 
      string back to its native Decimal type. */
      cevent->Value = Decimal::Parse( cevent->Value->ToString(),
         NumberStyles::Currency, nullptr );
   }

private void BindTextBoxControl()
{
    DataSet myDataSet = new DataSet();
    /* Insert code to populate the DataSet with tables, 
       columns, and data. 
     */

    // Creates a new Binding object. 
    Binding myBinding = new Binding("Text", myDataSet
,
        "customers.custToOrders.OrderAmount");

    // Adds event delegates for the Parse and Format events.
    myBinding.add_Parse(new ConvertEventHandler(CurrencyToDecimal));
    myBinding.add_Format(new ConvertEventHandler(DecimalToCurrency));

    // Adds the new Binding to the BindingsCollection.
    text1.get_DataBindings().Add(myBinding);
} //BindTextBoxControl

private void DecimalToCurrency(Object sender,
 ConvertEventArgs cevent)
{
    /* This method is the Format event handler. Whenever the 
       control displays a new value, the value is converted from
 
       its native Decimal type to a string. The ToString method
 
       then formats the value as a Currency, by using the 
       formatting character "c". 
     */
    cevent.set_Value(((System.Decimal)(cevent.get_Value())).ToString("c"));
} //DecimalToCurrency

private void CurrencyToDecimal(Object sender,
 ConvertEventArgs cevent)
{
    /* This method is the Parse event handler. The Parse event 
       occurs whenever the displayed value changes. The static
 
       Parse method of the Decimal structure converts the 
       string back to its native Decimal type. 
     */
    cevent.set_Value(Decimal.Parse(cevent.get_Value().ToString(),
        NumberStyles.Currency, null));
} //CurrencyToDecimal

継承階層

System.Object
   System.MarshalByRefObject
     System.Windows.Forms.BaseCollection
      System.Windows.Forms.BindingsCollection
         System.Windows.Forms.ControlBindingsCollection

スレッドセーフ

この型の public static (Visual Basic では Shared) メンバはすべて、スレッドセーフです。インスタンスメンバの場合は、スレッドセーフであるとは限りません。

プラットフォーム

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition