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ExceptionValidationRule Class
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ExceptionValidationRule Class

Represents a rule that checks for exceptions that are thrown during the update of the binding source property.


Namespace:  System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation

public ref class ExceptionValidationRule sealed : public ValidationRule
<ExceptionValidationRule .../>

The ExceptionValidationRule type exposes the following members.

Public methodExceptionValidationRuleInitializes a new instance of the ExceptionValidationRule class.

Public propertyValidatesOnTargetUpdatedGets or sets a value that indicates whether the validation rule runs when the target of the Binding is updated. (Inherited from ValidationRule.)
Public propertyValidationStepGets or sets when the validation rule runs. (Inherited from ValidationRule.)

Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodValidate(Object, CultureInfo)Performs validation checks on a value. (Overrides ValidationRule::Validate(Object, CultureInfo).)
Public methodValidate(Object, CultureInfo, BindingExpressionBase)Performs validation checks on a value. (Inherited from ValidationRule.)
Public methodValidate(Object, CultureInfo, BindingGroup)Performs validation checks on a value. (Inherited from ValidationRule.)

The WPF data binding model enables you to associate ValidationRules with a Binding object. The ExceptionValidationRule class is a built-in rule that checks for exceptions that are thrown during the updates of the binding source property. You can provide custom logic to specify how the binding engine handles these exceptions by using a UpdateSourceExceptionFilterCallback. For more information, see UpdateSourceExceptionFilter.

An alternative syntax to setting the ExceptionValidationRule explicitly is to set the ValidatesOnExceptions property to true on your Binding or MultiBinding object.

You can create a custom rule by creating a class that derives from ValidationRule. For more information and a detailed discussion of data validation, see Data Binding Overview.

The ValidationRules property takes a collection of ValidationRule objects. The following example uses TextBox::Text as the binding target property and StartPrice (an integer) as the binding source property. When the user enters a value that cannot be converted to an integer, an exception is thrown, which causes the ExceptionValidationRule to invalidate the target value.

<TextBox Name="StartPriceEntryForm" Grid.Row="2" Grid.Column="1"
    Style="{StaticResource textStyleTextBox}" Margin="8,5,0,5">
    <Binding Path="StartPrice" UpdateSourceTrigger="PropertyChanged">
        <ExceptionValidationRule />

By default, when there is a validation error, the TextBox appears with a red border. Optionally, you can write a custom ErrorTemplate to specify how you want to notify the user when there is a validation error.

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

For the complete sample, see Data Binding Demo.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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