Control.LostFocus Control.LostFocus Control.LostFocus Control.LostFocus Event

定義

コントロールがフォーカスを失ったときに発生します。Occurs when the control loses focus.

public:
 event EventHandler ^ LostFocus;
[System.ComponentModel.Browsable(false)]
public event EventHandler LostFocus;
member this.LostFocus : EventHandler 
Public Custom Event LostFocus As EventHandler 
属性

次のコード例では、TextBox1 のテキストを検証を示します。The following code example demonstrates validating the text for TextBox1. 処理も示しています、LostFocusイベントを設定して、 FileDialog.InitialDirectory TextBox1 でテキストのプロパティ。It also demonstrates handling the LostFocus event by setting the FileDialog.InitialDirectory property to the text in TextBox1. 使用しているコード例、ErrorProvider.GetErrorファイル ダイアログ ボックスを開く前に、エラーをチェックするメソッド。The code example used the ErrorProvider.GetError method to check for an error before opening the file dialog box. この例を実行するには、含まれているフォームに次のコードを貼り付けます、TextBoxという名前TextBox1OpenFileDialogという名前OpenFileDialog1Buttonという名前Button1、およびErrorProviderというErrorProvider1To run this example, paste the following code into a form containing a TextBox named TextBox1, an OpenFileDialog named OpenFileDialog1, a Button named Button1, and an ErrorProvider named ErrorProvider1. すべてのイベントがイベント ハンドラーに関連付けられていることを確認します。Ensure all events are associated with their event handlers.

private:
   void TextBox1_Validating( Object^ sender,
      System::ComponentModel::CancelEventArgs^ e )
   {
      // If nothing is entered,
      // an ArgumentException is caught; if an invalid directory is entered, 
      // a DirectoryNotFoundException is caught. An appropriate error message 
      // is displayed in either case.
      try
      {
         System::IO::DirectoryInfo^ directory = gcnew System::IO::DirectoryInfo( TextBox1->Text );
         directory->GetFiles();
         ErrorProvider1->SetError( TextBox1, "" );
      }
      catch ( System::ArgumentException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "Please enter a directory" );
      }
      catch ( System::IO::DirectoryNotFoundException^ ) 
      {
         ErrorProvider1->SetError( TextBox1, "The directory does not exist."
         "Try again with a different directory." );
      }
   }

   // This method handles the LostFocus event for TextBox1 by setting the 
   // dialog's InitialDirectory property to the text in TextBox1.
   void TextBox1_LostFocus( Object^ sender, System::EventArgs^ e )
   {
      OpenFileDialog1->InitialDirectory = TextBox1->Text;
   }

   // This method demonstrates using the ErrorProvider.GetError method 
   // to check for an error before opening the dialog box.
   void Button1_Click( System::Object^ sender, System::EventArgs^ e )
   {
      //If there is no error, then open the dialog box.
      if ( ErrorProvider1->GetError( TextBox1 )->Equals( "" ) )
      {
         ::DialogResult dialogResult = OpenFileDialog1->ShowDialog();
      }
   }
private void textBox1_Validating(object sender, 
	System.ComponentModel.CancelEventArgs e)
{
	// If nothing is entered,
	// an ArgumentException is caught; if an invalid directory is entered, 
	// a DirectoryNotFoundException is caught. An appropriate error message 
	// is displayed in either case.
	try
	{
		System.IO.DirectoryInfo directory = 
			new System.IO.DirectoryInfo(textBox1.Text);
		directory.GetFiles();
		errorProvider1.SetError(textBox1, "");

	}
	catch(System.ArgumentException ex1)
	{
		errorProvider1.SetError(textBox1, "Please enter a directory");

	}
	catch(System.IO.DirectoryNotFoundException ex2)
	{
		errorProvider1.SetError(textBox1, "The directory does not exist." +
			"Try again with a different directory.");
	}

}

// This method handles the LostFocus event for textBox1 by setting the 
// dialog's InitialDirectory property to the text in textBox1.
private void textBox1_LostFocus(object sender, System.EventArgs e)
{
	openFileDialog1.InitialDirectory = textBox1.Text;
}

// This method demonstrates using the ErrorProvider.GetError method 
// to check for an error before opening the dialog box.
private void button1_Click(System.Object sender, System.EventArgs e)
{
	//If there is no error, then open the dialog box.
	if (errorProvider1.GetError(textBox1)=="")
	{
		DialogResult dialogResult = openFileDialog1.ShowDialog();
	}
}
Private Sub TextBox1_Validating(ByVal sender As Object, _
ByVal e As System.ComponentModel.CancelEventArgs) _
Handles TextBox1.Validating

    ' If nothing is entered,
    ' an ArgumentException is caught; if an invalid directory is entered, 
    ' a DirectoryNotFoundException is caught. An appropriate error message 
    ' is displayed in either case.
    Try
        Dim directory As New System.IO.DirectoryInfo(TextBox1.Text)
        directory.GetFiles()
        ErrorProvider1.SetError(TextBox1, "")

    Catch ex1 As System.ArgumentException
        ErrorProvider1.SetError(TextBox1, "Please enter a directory")

    Catch ex2 As System.IO.DirectoryNotFoundException
        ErrorProvider1.SetError(TextBox1, _
        "The directory does not exist." & _
        "Try again with a different directory.")
    End Try

End Sub

' This method handles the LostFocus event for TextBox1 by setting the 
' dialog's InitialDirectory property to the text in TextBox1.
Private Sub TextBox1_LostFocus(ByVal sender As Object, _
    ByVal e As System.EventArgs) Handles TextBox1.LostFocus
    OpenFileDialog1.InitialDirectory = TextBox1.Text
End Sub


' This method demonstrates using the ErrorProvider.GetError method 
' to check for an error before opening the dialog box.
Private Sub Button1_Click(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles Button1.Click

    'If there is no error, then open the dialog box.
    If ErrorProvider1.GetError(TextBox1) = "" Then
        Dim dialogResult As DialogResult = OpenFileDialog1.ShowDialog()
    End If

End Sub

注釈

呼び出すことによってキーボード (タブ、shift キーを押しながら TAB となど) を使用して、フォーカスを変更すると、SelectまたはSelectNextControlメソッド、または設定して、ContainerControl.ActiveControlプロパティを現在のフォームは、次の順序でフォーカス イベントが発生します。When you change the focus by using the keyboard (TAB, SHIFT+TAB, and so on), by calling the Select or SelectNextControl methods, or by setting the ContainerControl.ActiveControl property to the current form, focus events occur in the following order:

  1. Enter

  2. GotFocus

  3. Leave

  4. Validating

  5. Validated

  6. LostFocus

フォーカスを変更すると、マウスを使用して、または呼び出すことによって、Focusメソッドでは、次の順序でフォーカス イベントが発生します。When you change the focus by using the mouse or by calling the Focus method, focus events occur in the following order:

  1. Enter

  2. GotFocus

  3. LostFocus

  4. Leave

  5. Validating

  6. Validated

場合、CausesValidationプロパティに設定されてfalseValidatingValidatedイベントが抑制されます。If the CausesValidation property is set to false, the Validating and Validated events are suppressed.

場合、Cancelのプロパティ、CancelEventArgsに設定されているtrueで、Validatingイベント デリゲート、後に通常発生するすべてのイベント、Validatingイベントが抑制されます。If the Cancel property of the CancelEventArgs is set to true in the Validating event delegate, all events that would usually occur after the Validating event are suppressed.

注意

GotFocusLostFocusイベントは、低レベルのフォーカス イベント WM_KILLFOCUS と WM_SETFOCUS Windows メッセージに関連付けられています。The GotFocus and LostFocus events are low-level focus events that are tied to the WM_KILLFOCUS and WM_SETFOCUS Windows messages. 通常、GotFocusLostFocusイベントは、更新するときにのみ使用UICuesまたはカスタム コントロールを作成します。Typically, the GotFocus and LostFocus events are only used when updating UICues or when writing custom controls. 代わりに、EnterLeaveを除くすべてのコントロールのイベントを使用する必要があります、Formクラスを使用する、ActivatedDeactivateイベント。Instead the Enter and Leave events should be used for all controls except the Form class, which uses the Activated and Deactivate events. 詳細については、GotFocusLostFocusイベントを参照してください、 WM_KILLFOCUSWM_KILLFOCUSトピック。For more information about the GotFocus and LostFocus events, see the WM_KILLFOCUS and WM_KILLFOCUS topics.

注意事項

内からフォーカスを設定しないで、 EnterGotFocusLeaveLostFocusValidating、またはValidatedイベント ハンドラー。Do not attempt to set focus from within the Enter, GotFocus, Leave, LostFocus, Validating, or Validated event handlers. これには、アプリケーションまたはオペレーティング システムが応答を停止する可能性があります。Doing so can cause your application or the operating system to stop responding. 詳細については、次を参照してください。、 WM_KILLFOCUSトピック。For more information, see the WM_KILLFOCUS topic.

イベントの処理の詳細については、「処理とイベントの発生」を参照してください。For more information about handling events, see Handling and Raising Events.

適用対象

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