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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)

public sealed class ExceptionValidationRule : 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.)
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodGetHashCodeServes as a hash function for a particular type. (Inherited from Object.)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Protected methodMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Public methodValidatePerforms validation checks on a value. (Overrides ValidationRule.Validate(Object, CultureInfo).)

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, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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