Control.OnEnter(EventArgs) Control.OnEnter(EventArgs) Control.OnEnter(EventArgs) Control.OnEnter(EventArgs) Method

定義

Enter イベントを発生させます。Raises the Enter event.

protected:
 virtual void OnEnter(EventArgs ^ e);
protected virtual void OnEnter (EventArgs e);
abstract member OnEnter : EventArgs -> unit
override this.OnEnter : EventArgs -> unit
Protected Overridable Sub OnEnter (e As EventArgs)

パラメーター

e
EventArgs EventArgs EventArgs EventArgs

イベント データを格納している EventArgsAn EventArgs that contains the event data.

次のコード例ではEnter 、イベントを使用して、 TextBox特定の条件下でのの前景色と背景色を変更します。The following code example uses the Enter event to change the foreground and background colors of a TextBox under particular conditions.

private:
   void textBox1_Enter( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // If the TextBox contains text, change its foreground and background colors.
      if ( textBox1->Text != String::Empty )
      {
         textBox1->ForeColor = Color::Red;
         textBox1->BackColor = Color::Black;

         // Move the selection pointer to the end of the text of the control.
         textBox1->Select(textBox1->Text->Length,0);
      }
   }

   void textBox1_Leave( Object^ /*sender*/, System::EventArgs^ /*e*/ )
   {
      // Reset the colors and selection of the TextBox after focus is lost.
      textBox1->ForeColor = Color::Black;
      textBox1->BackColor = Color::White;
      textBox1->Select(0,0);
   }
private void textBox1_Enter(object sender, System.EventArgs e)
{
    // If the TextBox contains text, change its foreground and background colors.
    if (!string.IsNullOrEmpty(textBox1.Text))
    {
        textBox1.ForeColor = Color.Red;
        textBox1.BackColor = Color.Black;
        // Move the selection pointer to the end of the text of the control.
        textBox1.Select(textBox1.Text.Length, 0);
    }
}

private void textBox1_Leave(object sender, System.EventArgs e)
{
    // Reset the colors and selection of the TextBox after focus is lost.
    textBox1.ForeColor = Color.Black;
    textBox1.BackColor = Color.White;
    textBox1.Select(0,0);
}
    Private Sub textBox1_Enter(sender As Object, e As System.EventArgs) Handles textBox1.Enter
        ' If the TextBox contains text, change its foreground and background colors.
        If textBox1.Text <> [String].Empty Then
            textBox1.ForeColor = Color.Red
            textBox1.BackColor = Color.Black
            ' Move the selection pointer to the end of the text of the control.
            textBox1.Select(textBox1.Text.Length, 0)
        End If
    End Sub
   
   
    Private Sub textBox1_Leave(sender As Object, e As System.EventArgs) Handles textBox1.Leave
        ' Reset the colors and selection of the TextBox after focus is lost.
        textBox1.ForeColor = Color.Black
        textBox1.BackColor = Color.White
        textBox1.Select(0, 0)
    End Sub
End Class

注釈

イベントを発生させると、イベント ハンドラーがデリゲートから呼び出されます。Raising an event invokes the event handler through a delegate. 詳細については、次を参照してください。処理とイベントの発生します。For more information, see Handling and Raising Events.

OnEnter メソッドを使用すると、デリゲートを結び付けずに、派生クラスでイベントを処理することもできます。The OnEnter method also allows derived classes to handle the event without attaching a delegate. 派生クラスでイベントを処理する場合は、この手法をお勧めします。This is the preferred technique for handling the event in a derived class.

注意 (継承者)

派生クラスで OnEnter(EventArgs) をオーバーライドする場合は、登録されているデリゲートがイベントを受け取ることができるように、基本クラスの OnEnter(EventArgs) メソッドを呼び出してください。When overriding OnEnter(EventArgs) in a derived class, be sure to call the base class's OnEnter(EventArgs) method so that registered delegates receive the event.

適用対象

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