ValidatesOnTargetUpdated Property
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ValidationRule.ValidatesOnTargetUpdated Property


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

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

public bool ValidatesOnTargetUpdated { get; set; }

Property Value

Type: System.Boolean

true if the validation rule runs when the target of the Binding is updated; otherwise, false.

The following example checks whether the TextBox is empty. The ValidationRule, ValueIsNotNull, has ValidatesOnTargetUpdated set to true, so that when the application starts, the ValidationRule runs and displays a message if the TextBox is empty.

<TextBox Width="150"
    <Binding Source="{StaticResource myObject}"
        <src:ValueIsNotNull ValidatesOnTargetUpdated="True" />

The following example shows the ValidationRule that is used in the previous example and the event handler for the Error event.

public class ValueIsNotNull : ValidationRule
    public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
        string str = value as string;

        if (!string.IsNullOrEmpty(str))
            return ValidationResult.ValidResult;
            return new ValidationResult(false, "Value must not be null");

.NET Framework
Available since 3.0
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