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ValidationRule (Clase)

Provides a way to create a custom rule in order to check the validity of user input. This is an abstract class.

Espacio de nombres: System.Windows.Controls
Ensamblado: PresentationFramework (en presentationframework.dll)
Espacio de nombres XML:  http://schemas.microsoft.com/winfx/2006/xaml/presentation

public abstract class ValidationRule
public abstract class ValidationRule
public abstract class ValidationRule
Esta clase es abstracta; vea en Jerarquía de herencia las clases derivadas no abstractas utilizables en XAML.

When you use the WPF data binding model, you can associate ValidationRules with your binding object. To create custom rules, make a subclass of this class and implement the Validate method. Optionally, use the built-in ExceptionValidationRule, which catches exceptions that are thrown during source updates.

The binding engine checks each ValidationRule that is associated with a binding every time it transfers an input value, which is the binding target property value, to the binding source property.

For detailed information about data validation, see Data Binding Overview.

For information about how to validate user-provided data in a dialog box, see Dialog Boxes Overview.

The following example shows how to implement a validation rule. The input value is invalid if it contains non-numeric characters or if it is outside the lower and upper bounds. If the value of the returned ValidationResult is invalid, the ErrorContent property is set to the appropriate error message and the IsValid property is set to false.

For the complete example, see Implement Binding Validation.

public class AgeRangeRule : ValidationRule
{
    private int _min;
    private int _max;

    public AgeRangeRule()
    {
    }

    public int Min
    {
        get { return _min; }
        set { _min = value; }
    }

    public int Max
    {
        get { return _max; }
        set { _max = value; }
    }

    public override ValidationResult Validate(object value, CultureInfo cultureInfo)
    {
        int age = 0;

        try
        {
            if (((string)value).Length > 0)
                age = Int32.Parse((String)value);
        }
        catch (Exception e)
        {
            return new ValidationResult(false, "Illegal characters or " + e.Message);
        }

        if ((age < Min) || (age > Max))
        {
            return new ValidationResult(false,
              "Please enter an age in the range: " + Min + " - " + Max + ".");
        }
        else
        {
            return new ValidationResult(true, null);
        }
    }
}

Los miembros estáticos públicos (Shared en Visual Basic) de este tipo son seguros para la ejecución de subprocesos. No se garantiza que los miembros de instancias sean seguros para la ejecución de subprocesos.

Microsoft .NET Framework 3.0 es compatible con Windows Vista, Microsoft Windows XP SP2 y Windows Server 2003 SP1.

.NET Framework

Compatible con: 3.0

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