ExceptionValidationRule Class
[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]
Represents a rule that checks for exceptions that are thrown during the update of the binding source property.
System.Windows.Controls.ValidationRule
System.Windows.Controls.ExceptionValidationRule
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
The ExceptionValidationRule type exposes the following members.
| Name | Description | |
|---|---|---|
 | ExceptionValidationRule | Initializes a new instance of the ExceptionValidationRule class. |
| Name | Description | |
|---|---|---|
| ValidatesOnTargetUpdated | Gets or sets a value that indicates whether the validation rule runs when the target of the Binding is updated. (Inherited from ValidationRule.) |
| ValidationStep | Gets or sets when the validation rule runs. (Inherited from ValidationRule.) |
| Name | Description | |
|---|---|---|
| Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
| Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
| GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
| GetType | Gets the Type of the current instance. (Inherited from Object.) |
| MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
| ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Validate(Object, CultureInfo) | Performs validation checks on a value. (Overrides ValidationRule.Validate(Object, CultureInfo).) |
| Validate(Object, CultureInfo, BindingExpressionBase) | Performs validation checks on a value. (Inherited from ValidationRule.) |
| Validate(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"> <TextBox.Text> <Binding Path="StartPrice" UpdateSourceTrigger="PropertyChanged"> <Binding.ValidationRules> <ExceptionValidationRule /> </Binding.ValidationRules> </Binding> </TextBox.Text> </TextBox>
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.
Windows 8 Consumer Preview, Windows Server 8 Beta, Windows 7, Windows Server 2008 SP2, Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
