Control.CausesValidation Свойство

Определение

Возвращает или задает значение, указывающее, вызывает ли элемент управления выполнение проверки для всех элементов управления, требующих проверки, при получении фокуса.Gets or sets a value indicating whether the control causes validation to be performed on any controls that require validation when it receives focus.

public:
 property bool CausesValidation { bool get(); void set(bool value); };
public bool CausesValidation { get; set; }
member this.CausesValidation : bool with get, set
Public Property CausesValidation As Boolean

Значение свойства

Значение true, если элемент управления вызывает выполнение проверки в любом элементе управления, требующем проверки при получении фокуса; в противном случае — значение false.true if the control causes validation to be performed on any controls requiring validation when it receives focus; otherwise, false. Значение по умолчанию — true.The default is true.

Примеры

В следующем примере кода используется производный класс TextBox и проверяется адрес электронной почты, который вводит пользователь.The following code example uses the derived class TextBox and validates an email address that the user enters. Если адрес электронной почты имеет формат, отличный от стандартного (содержащий "@" and "."), проверка завершается неудачно, отображается значок ErrorProvider, и событие отменяется.If the email address is not in the standard format (containing "@" and "."), the validation fails, an ErrorProvider icon is displayed, and the event is canceled. У одной из кнопок формы свойство CausesValidation имеет значение false.One of the buttons on the form has its CausesValidation property set to false. Если щелкнуть или установить фокус на эту кнопку, проверка не будет активирована.Clicking or setting focus to this button does not trigger validation. В этом примере требуется, чтобы в форме были созданы TextBox, элемент управления ErrorProvider и Button.This example requires that a TextBox, an ErrorProvider control, and a Button have been created on a form.

public:
   Form1()
   {
      InitializeComponent();    
      //Set button2 to be non-validating.
      this->button2->CausesValidation = false;
   }

private:
   void textBox1_Validating( Object^ sender, System::ComponentModel::CancelEventArgs^ e )
   {
      String^ errorMsg;
      if ( !ValidEmailAddress( textBox1->Text, &errorMsg ) )
      {
         // Cancel the event and select the text to be corrected by the user.
         e->Cancel = true;
         textBox1->Select( 0, textBox1->Text->Length );
         
         // Set the ErrorProvider error with the text to display.
         this->errorProvider1->SetError( textBox1, errorMsg );
      }
   }

   void textBox1_Validated( Object^ sender, System::EventArgs^ e )
   {
      // If all conditions have been met, clear the ErrorProvider of errors.
      errorProvider1->SetError( textBox1, "" );
   }

public:
   bool ValidEmailAddress( String^ emailAddress, [Out]interior_ptr<String^> errorMessage )
   {
      // Confirm that the email address String* is not empty.
      if ( emailAddress->Length == 0 )
      {
         *errorMessage = "email address is required.";
         return false;
      }

      // Confirm that there is an "@" and a "." in the email address, and in the correct order.
      if ( emailAddress->IndexOf( "@" ) > -1 )
      {
         if ( emailAddress->IndexOf( ".", emailAddress->IndexOf( "@" ) ) > emailAddress->IndexOf( "@" ) )
         {
            *errorMessage = "";
            return true;
         }
      }

      *errorMessage = "email address must be valid email address format.\n" +
         "For example 'someone@example.com' ";
      return false;
   }
public Form1()
{
    InitializeComponent();
    //Set button2 to be non-validating.
    this.button2.CausesValidation = false;
}


private void textBox1_Validating(object sender, 
                System.ComponentModel.CancelEventArgs e)
{
   string errorMsg;
   if(!ValidEmailAddress(textBox1.Text, out errorMsg))
   {
      // Cancel the event and select the text to be corrected by the user.
      e.Cancel = true;
      textBox1.Select(0, textBox1.Text.Length);

      // Set the ErrorProvider error with the text to display. 
      this.errorProvider1.SetError(textBox1, errorMsg);
   }
}

private void textBox1_Validated(object sender, System.EventArgs e)
{
   // If all conditions have been met, clear the ErrorProvider of errors.
   errorProvider1.SetError(textBox1, "");
}
public bool ValidEmailAddress(string emailAddress, out string errorMessage)
{
   // Confirm that the email address string is not empty.
   if(emailAddress.Length == 0)
   {
      errorMessage = "email address is required.";
         return false;
   }

   // Confirm that there is an "@" and a "." in the email address, and in the correct order.
   if(emailAddress.IndexOf("@") > -1)
   {
      if(emailAddress.IndexOf(".", emailAddress.IndexOf("@") ) > emailAddress.IndexOf("@") )
      {
         errorMessage = "";
         return true;
      }
   }
   
   errorMessage = "email address must be valid email address format.\n" +
      "For example 'someone@example.com' ";
      return false;
}
    Public Sub New()
        MyBase.New()

        InitializeComponent()
        'Set button2 to be non-validating.
        Me.button2.CausesValidation = False
    End Sub

   Private Function ValidEmailAddress(ByVal emailAddress As String, ByRef errorMessage As String) As Boolean
      ' Confirm there is text in the control.
      If textBox1.Text.Length = 0 Then
         errorMessage = "Email address is required."
         Return False

      End If

      ' Confirm that there is an "@" and a "." in the email address, and in the correct order.
      If emailAddress.IndexOf("@") > -1 Then
         If (emailAddress.IndexOf(".", emailAddress.IndexOf("@")) > emailAddress.IndexOf("@")) Then
            errorMessage = ""
            Return True
         End If
      End If

      errorMessage = "Email address must be valid email address format." + ControlChars.Cr + _
        "For example 'someone@example.com' "
      Return False
End Function

   Private Sub textBox1_Validating(ByVal sender As Object, _
   ByVal e As System.ComponentModel.CancelEventArgs) Handles textBox1.Validating

      Dim errorMsg As String
      If Not ValidEmailAddress(textBox1.Text, errorMsg) Then
         ' Cancel the event and select the text to be corrected by the user.
         e.Cancel = True
         textBox1.Select(0, textBox1.Text.Length)

         ' Set the ErrorProvider error with the text to display. 
         Me.errorProvider1.SetError(textBox1, errorMsg)
      End If
   End Sub


   Private Sub textBox1_Validated(ByVal sender As Object, _
   ByVal e As System.EventArgs) Handles textBox1.Validated
      ' If all conditions have been met, clear the error provider of errors.
      errorProvider1.SetError(textBox1, "")
   End Sub

Комментарии

Если свойство CausesValidation имеет значение false, события Validating и Validated подавляются.If the CausesValidation property is set to false, the Validating and Validated events are suppressed.

Значение свойства CausesValidation обычно устанавливается равным false для таких элементов управления, как кнопка справки.The CausesValidation property value is typically set to false for controls such as a Help button.

Применяется к

Дополнительно