Control.BindingContext プロパティ

.NET Framework クラス ライブラリ リファレンス

Control.BindingContext プロパティ

コントロールの BindingContext を取得または設定します。

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 Overridable Property
 BindingContext As BindingContext

Visual Basic (使用法)

Dim instance As Control
Dim value As BindingContext

value = instance.BindingContext

instance.BindingContext = value

C#

public virtual BindingContext BindingContext { get;
 set; }

C++

public:
virtual property BindingContext^ BindingContext {
    BindingContext^ get ();
    void set (BindingContext^ value);
}

J#

/** @property */
public BindingContext get_BindingContext ()

/** @property */
public void set_BindingContext (BindingContext
 value)

JScript

public function get BindingContext
 () : BindingContext

public function set BindingContext
 (value : BindingContext)

プロパティ値
コントロールの BindingContext。

解説

Control の BindingContext を使用して、Control に含まれるすべてのデータ バインド コントロールの単一の BindingManagerBase を返します。BindingManagerBase は、同期をとっている同一のデータ ソースにバインドされたすべてのコントロールを維持します。たとえば、BindingManagerBase の Position プロパティを設定して、すべてのデータ連結コントロールが指している、基になるリストの項目を指定します。

新しい BindingContext の作成方法とそれを BindingContext プロパティに割り当てる方法の詳細については、BindingContext のトピックを参照してください。

継承時の注意 派生クラスで BindingContext プロパティをオーバーライドする場合は、基本クラスの BindingContext プロパティを使用して、基本の実装を拡張します。それ以外の場合は、すべての実装を提供する必要があります。BindingContext プロパティの get アクセサと set アクセサの両方をオーバーライドする必要はありません。必要に応じて 1 つのアクセサだけをオーバーライドできます。

使用例

4 つの Binding オブジェクトを作成して、5 つのコントロール (1 つの DateTimePicker コントロールと 4 つの TextBox コントロール) を複数のデータ ソースにバインドするコード例を次に示します。さらに、BindingContext を使用して、各データ ソースの BindingManagerBase を取得します。

Visual Basic

Protected Sub BindControls()

   ' Create two Binding objects for the first two TextBox 
   '   controls. The data-bound property for both controls 
   '   is the Text property. The data source is a DataSet 
   '   (ds). The data member is the string 
   '   "TableName.ColumnName".
   text1.DataBindings.Add(New Binding _
      ("Text", ds, "customers.custName"))
   text2.DataBindings.Add(New Binding _
      ("Text", ds, "customers.custID"))
   
   ' Bind the DateTimePicker control by adding a new Binding. 
   '   The data member of the DateTimePicker is a 
   '   TableName.RelationName.ColumnName string.
   DateTimePicker1.DataBindings.Add(New Binding _
      ("Value", ds, "customers.CustToOrders.OrderDate"))

   ' Add event delegates for the Parse and Format events to a 
   '   new Binding object, and add the object to the third 
   '   TextBox control's BindingsCollection. The delegates 
   '   must be added before adding the Binding to the 
   '   collection; otherwise, no formatting occurs until 
   '   the Current object of the BindingManagerBase for 
   '   the data source changes.
   Dim b As Binding = New
 Binding _
      ("Text", ds, "customers.custToOrders.OrderAmount")
   AddHandler b.Parse,  New ConvertEventHandler(AddressOf
 CurrencyStringToDecimal)      
   AddHandler b.Format, New ConvertEventHandler(AddressOf
 DecimalToCurrencyString)
   text3.DataBindings.Add(b)

   ' Get the BindingManagerBase for the Customers table.
   bmCustomers = Me.BindingContext(ds, "Customers")

   ' Get the BindingManagerBase for the Orders table using the 
   '   RelationName.
   bmOrders = Me.BindingContext(ds, "customers.CustToOrders")

   ' Bind the fourth TextBox control's Text property to the
   ' third control's Text property.
   text4.DataBindings.Add("Text", text3, "Text")

End Sub

C#

protected void BindControls()
{
   /* Create two Binding objects for the first two TextBox 
      controls. The data-bound property for both controls 
      is the Text property. The data source is a DataSet 
      (ds). The data member is a navigation path in the form:
 
      "TableName.ColumnName". */
   text1.DataBindings.Add(new Binding
   ("Text", ds, "customers.custName"));
   text2.DataBindings.Add(new Binding
   ("Text", ds, "customers.custID"));
   
   /* Bind the DateTimePicker control by adding a new Binding.
 
      The data member of the DateTimePicker is a navigation path:
      TableName.RelationName.ColumnName string. */
   DateTimePicker1.DataBindings.Add(new 
   Binding("Value", ds, "customers.CustToOrders.OrderDate"));

   /* Add event delegates for the Parse and Format events to a
 
      new Binding object, and add the object to the third 
      TextBox control's BindingsCollection. The delegates 
      must be added before adding the Binding to the 
      collection; otherwise, no formatting occurs until 
      the Current object of the BindingManagerBase for 
      the data source changes. */
      Binding b = new Binding
      ("Text", ds, "customers.custToOrders.OrderAmount");
   b.Parse+=new ConvertEventHandler(CurrencyStringToDecimal);
   b.Format+=new ConvertEventHandler(DecimalToCurrencyString);
   text3.DataBindings.Add(b);

   // Get the BindingManagerBase for the Customers table. 
   bmCustomers = this.BindingContext [ds, "Customers"];

   /* Get the BindingManagerBase for the Orders table using
 the 
      RelationName. */ 
   bmOrders = this.BindingContext[ds, "customers.CustToOrders"];

   /* Bind the fourth TextBox control's Text property to the
   third control's Text property. */
   text4.DataBindings.Add("Text", text3, "Text");
}

C++

void BindControls()
{
   /* Create two Binding objects for the first two TextBox 
         controls. The data-bound property for both controls 
         is the Text property. The data source is a DataSet 
         (ds). The data member is a navigation path in the form:
 
         "TableName.ColumnName". */
   text1->DataBindings->Add( gcnew Binding( "Text",ds,"customers.custName"
 ) );
   text2->DataBindings->Add( gcnew Binding( "Text",ds,"customers.custID"
 ) );

   /* Bind the DateTimePicker control by adding a new Binding.
 
         The data member of the DateTimePicker is a navigation path:
         TableName.RelationName.ColumnName string. */
   DateTimePicker1->DataBindings->Add( gcnew Binding( "Value",ds,"customers.CustToOrders.OrderDate"
 ) );

   /* Add event delegates for the Parse and Format events to a
 
         new Binding object, and add the object to the third 
         TextBox control's BindingsCollection. The delegates 
         must be added before adding the Binding to the 
         collection; otherwise, no formatting occurs until 
         the Current object of the BindingManagerBase for 
         the data source changes. */
   Binding^ b = gcnew Binding( "Text",ds,"customers.custToOrders.OrderAmount"
 );
   b->Parse += gcnew ConvertEventHandler( this, &Form1::CurrencyStringToDecimal
 );
   b->Format += gcnew ConvertEventHandler( this, &Form1::DecimalToCurrencyString
 );
   text3->DataBindings->Add( b );

   // Get the BindingManagerBase for the Customers table. 
   bmCustomers = this->BindingContext[ ds,"Customers"
 ];

   /* Get the BindingManagerBase for the Orders table using
 the 
         RelationName. */
   bmOrders = this->BindingContext[ds, "customers.CustToOrders"];

   /* Bind the fourth TextBox control's Text property to the
      third control's Text property. */
   text4->DataBindings->Add( "Text", text3, "Text" );
}

J#

protected void BindControls()
{
    /* Create two Binding objects for the first two TextBox 
       controls. The data-bound property for both controls 
       is the Text property. The data source is a DataSet 
       (ds). The data member is a navigation path in the form:
 
       "TableName.ColumnName". 
     */
    text1.get_DataBindings().Add(new Binding("Text",
 ds, 
        "customers.custName"));
    text2.get_DataBindings().Add(new Binding("Text",
 ds, 
        "customers.custID"));

    /* Bind the DateTimePicker control by adding a new Binding.
 
       The data member of the DateTimePicker is a navigation path:
       TableName.RelationName.ColumnName string. 
     */
    dateTimePicker1.get_DataBindings().Add(new Binding("Value",
 ds, 
        "customers.CustToOrders.OrderDate"));

    /* Add event delegates for the Parse and Format events to a
 
       new Binding object, and add the object to the third 
       TextBox control's BindingsCollection. The delegates 
       must be added before adding the Binding to the 
       collection; otherwise, no formatting occurs until 
       the Current object of the BindingManagerBase for 
       the data source changes. 
     */
    Binding b = new Binding("Text", ds, 
        "customers.custToOrders.OrderAmount");

    b.add_Parse(new ConvertEventHandler(CurrencyStringToDecimal));
    b.add_Format(new ConvertEventHandler(DecimalToCurrencyString));
    text3.get_DataBindings().Add(b);

    // Get the BindingManagerBase for the Customers table. 
    bmCustomers = this.get_BindingContext().get_Item(ds, "Customers");

    /* Get the BindingManagerBase for the Orders table using
 the 
       RelationName. 
     */
    bmOrders = this.get_BindingContext().get_Item(ds, 
        "customers.CustToOrders");

    /* Bind the fourth TextBox control's Text property to the
       third control's Text property. 
     */
    text4.get_DataBindings().Add("Text", text3, "Text");
} //BindControls

JScript

  protected function BindControls()
  {
     /* Create two Binding objects for the first two TextBox 
        controls. The data-bound property for both controls 
        is the Text property. The data source is a DataSet 
        (ds). The data member is the string 
        "TableName.ColumnName". */
     text1.DataBindings.Add(new Binding
     ("Text", ds, "customers.custName"));
     text2.DataBindings.Add(new Binding
     ("Text", ds, "customers.custID"));
     
     /* Bind the DateTimePicker control by adding a new Binding.
 
        The data member of the DateTimePicker is a 
        TableName.RelationName.ColumnName string. */
     DateTimePicker1.DataBindings.Add(new 
     Binding("Value", ds, "customers.CustToOrders.OrderDate"));

     /* Add event delegates for the Parse and Format events to a
 
        new Binding object, and add the object to the third 
        TextBox control's BindingsCollection. The delegates 
        must be added before adding the Binding to the 
        collection; otherwise, no formatting occurs until 
        the Current object of the BindingManagerBase for 
        the data source changes. */
     var b : Binding = new Binding
        ("Text", ds, "customers.custToOrders.OrderAmount");
     b.add_Parse(CurrencyStringToDecimal);
     b.add_Format(DecimalToCurrencyString);
     text3.DataBindings.Add(b);

     // Get the BindingManagerBase for the Customers table. 
     bmCustomers = this.BindingContext [ds, "Customers"];

     /* Get the BindingManagerBase for the Orders table using
 the 
        RelationName. */ 
     bmOrders = this.BindingContext[ds, "customers.CustToOrders"];
  }

  private function DecimalToCurrencyString(sender,
 cevent : 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". */

     // We can only convert to string type. 
     if(cevent.DesiredType != String.GetType()) return;

     cevent.Value = (Decimal(cevent.Value)).ToString("c");
  }

  private function CurrencyStringToDecimal(sender,
 cevent : ConvertEventArgs)
  {   
     /* This method is the Parse event-handler. The Parse event 
        occurs whenever the displayed value changes. The static
 
        ToDecimal method of the Convert class converts the 
        value back to its native Decimal type. */

     // Can only convert to Decimal type.
     if(cevent.DesiredType != Decimal.GetType()) return;

     cevent.Value = Decimal.Parse(cevent.Value.ToString(),
         NumberStyles.Currency, null);

     /* To see that no precision is lost, print the unformatted 
        value. For example, changing a value to "10.0001" 
        causes the control to display "10.00", but the 
        unformatted value remains "10.0001". */
     Console.WriteLine(cevent.Value);
  }

  protected function button1_Click(sender,
 e : System.EventArgs)
  {
     // Go to the previous item in the Customer list.
     bmCustomers.Position -= 1;
  }

  protected function button2_Click(sender,
 e : System.EventArgs)
  {
     // Go to the next item in the Customer list.
     bmCustomers.Position += 1;
  }
   
  protected function button3_Click(sender,
 e : System.EventArgs)
  {
     // Go to the previous item in the Orders list.
     bmOrders.Position-=1;
  }

  protected function button4_Click(sender,
 e : System.EventArgs)
  {
     // Go to the next item in the Orders list.
     bmOrders.Position+=1;
  }

  // Create a DataSet with two tables and populate it.
  private function MakeDataSet()
  {
     // Create a DataSet.
     ds = new DataSet("myDataSet");
     
     // Create two DataTables.
     var tCust : DataTable = new DataTable("Customers");
     var tOrders : DataTable= new DataTable("Orders");

     // Create two columns, and add them to the first table.
     var cCustID : DataColumn = new DataColumn("CustID",
 Int32);
     var cCustName : DataColumn = new DataColumn("CustName");
     tCust.Columns.Add(cCustID);
     tCust.Columns.Add(cCustName);

     // Create three columns, and add them to the second table.
     var cID : DataColumn  = 
        new DataColumn("CustID", Int32);
     var cOrderDate : DataColumn  = 
        new DataColumn("orderDate", DateTime);
     var cOrderAmount : DataColumn = 
        new DataColumn("OrderAmount", Decimal);
     tOrders.Columns.Add(cOrderAmount);
     tOrders.Columns.Add(cID);
     tOrders.Columns.Add(cOrderDate);

     // Add the tables to the DataSet.
     ds.Tables.Add(tCust);
     ds.Tables.Add(tOrders);

     // Create a DataRelation, and add it to the DataSet.
     var dr : DataRelation = new DataRelation
     ("custToOrders", cCustID , cID);
     ds.Relations.Add(dr);
  
     /* Populate the tables. For each customer and order, 
        create need two DataRow variables. */
     var newRow1 : DataRow;
     var newRow2 : DataRow;

     // Create three customers in the Customers Table.
     for(var i : int = 1;
 i < 4; i++)
     {
        newRow1 = tCust.NewRow();
        newRow1["custID"] = i;
        // Add the row to the Customers table.
        tCust.Rows.Add(newRow1);
     }
     // Give each customer a distinct name.
     tCust.Rows[0]["custName"] = "Alpha";
     tCust.Rows[1]["custName"] = "Beta";
     tCust.Rows[2]["custName"] = "Omega";
     
     // For each customer, create five rows in the Orders table.
     for(var j : int = 1;
 j < 4; j++)
     {
        for(var k : int
 = 1; k < 6; k++)
        {
           newRow2 = tOrders.NewRow();
           newRow2["CustID"]= j;
           newRow2["orderDate"]= new DateTime(2001,
 j, k * 2);
           newRow2["OrderAmount"] = j * 10 + k  * .1;
           // Add the row to the Orders table.
           tOrders.Rows.Add(newRow2);
        }
     }
  }
}

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

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
.NET Compact Framework
サポート対象 : 2.0、1.0

参照

関連項目
Control クラス
Control メンバ
System.Windows.Forms 名前空間
BindingContextChanged
Binding クラス
BindingManagerBase クラス