ValidationRule Class
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ValidationRule Class


Provides a way to create a custom rule in order to check the validity of user input.

Namespace:   System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)

public abstract class ValidationRule


Initializes a new instance of the ValidationRule class.

System_CAPS_protmethodValidationRule(ValidationStep, Boolean)

Initializes a new instance of the ValidationRule class with the specified validation step and a value that indicates whether the validation rule runs when the target is updated.


Gets or sets a value that indicates whether the validation rule runs when the target of the Binding is updated.


Gets or sets when the validation rule runs.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)

System_CAPS_pubmethodValidate(Object, CultureInfo)

When overridden in a derived class, performs validation checks on a value.

System_CAPS_pubmethodValidate(Object, CultureInfo, BindingExpressionBase)

Performs validation checks on a value.

System_CAPS_pubmethodValidate(Object, CultureInfo, BindingGroup)

Performs validation checks on a value.

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, or the DataErrorValidationRule, which checks for errors raised by the IDataErrorInfo implementation of the source object.

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 How to: Implement Binding Validation.

.NET Framework
Available since 3.0

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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