Control.CausesValidation Propiedad

Definición

Espacio de nombres:

System.Windows.Forms

Ensamblado:

System.Windows.Forms.dll

Obtiene o establece un valor que indica si el control hace que se realice una validación de todos los controles que requieren validación cuando reciben el foco.

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

Valor de propiedad

Boolean

Es true si el control hace que se validen los controles que requieren validación cuando reciben el foco; en caso contrario, es false. De manera predeterminada, es true.

Ejemplos

En el ejemplo de código siguiente se usa la clase TextBox derivada y se valida una dirección de correo electrónico que el usuario escribe. Si la dirección de correo electrónico no está en el formato estándar (que contiene "@" y "."), se produce un error en la validación, se muestra un ErrorProvider icono y se cancela el evento. Uno de los botones del formulario tiene su CausesValidation propiedad establecida en false. Al hacer clic o establecer el foco en este botón, no se desencadena la validación. En este ejemplo se requiere que se haya creado un TextBox, un ErrorProvider control y un Button en un formulario.

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

Comentarios

Si la CausesValidation propiedad se establece falseen , se suprimen los Validating eventos y Validated .

Normalmente, el CausesValidation valor de la propiedad se establece false en para controles como un botón Ayuda.

Consulte también

• Validating
• Validated