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Xamarin Community Toolkit ValidationBehavior

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The ValidationBehavior allows users to create custom validation behaviors. All of the validation behaviors in the Xamarin Community Toolkit inherit from this behavior, to expose a number of shared properties. Users can inherit from this class to create a custom validation behavior currently not supported through the Xamarin Community Toolkit.

Properties

Property Type Description
ForceValidateCommand ICommand Allows the user to provide a custom ICommand that handles forcing validation. This is a bindable property.
Flags ValidationFlags Provides an enumerated value that specifies how to handle validation. This is a bindable property.
InvalidStyle Style The Style to apply to the element when validation fails. This is a bindable property.
IsNotValid bool Indicates whether or not the current value is considered invalid. This is a bindable property.
IsValid bool Indicates whether or not the current value is considered valid. This is a bindable property.
ValidStyle Style The Style to apply to the element when validation is successful.
Value object The value to validate. This is a bindable property.
ValuePropertyName string Allows the user to override the property that will be used as the value to validate. This is a bindable property.

Visual States

ValidationBehavior defines two visual states, Valid and Invalid, that can be used with the Visual State Manager, instead of the InvalidStyle and ValidStyle properties.

Usage sample:

<Entry Placeholder="Type characters...">
	<Entry.Behaviors>
		<xct:CharactersValidationBehavior
				Flags="ValidateOnValueChanging"
				CharacterType="{Binding SelectedItem, Source={x:Reference CharacterTypePicker}}"
				MaximumCharacterCount="{Binding Text, Source={x:Reference MaximumCharacterCountEntry}}"
				MinimumCharacterCount="{Binding Text, Source={x:Reference MinimumCharacterCountEntry}}"/>
	</Entry.Behaviors>

	<VisualStateManager.VisualStateGroups>
		<VisualStateGroup x:Name="CommonStates">
			<VisualState x:Name="Valid">
				<VisualState.Setters>
					<Setter Property="TextColor" Value="Green"/>
				</VisualState.Setters>
			</VisualState>
			<VisualState x:Name="Invalid">
				<VisualState.Setters>
					<Setter Property="TextColor" Value="IndianRed"/>
				</VisualState.Setters>
			</VisualState>
		</VisualStateGroup>
	</VisualStateManager.VisualStateGroups>
</Entry>

Sample

Warning

This class should not be used without inheriting from it. Therefore, there is no sample available.

API