},System.Func{--1,System.Boolean},System.String)} },System.Func{--1,System.Boolean},System.Func{--1,System.String})} ,System.String)} ,System.Func{--1,System.Boolean},System.Func{--1,System.String})} )} )} },System.IObservable{System.Boolean},System.String)} },System.IObservable{--2},System.Func{--2,System.Boolean},System.Func{--2,System.String})} },System.IObservable{ReactiveUI.Validation.States.IValidationState})} },System.IObservable{--2})}

ValidatableViewModelExtensions.ValidationRule(TViewModel, Expression>, Func, string) method¶

Defined in

Type: ValidatableViewModelExtensions Namespace: ReactiveUI.Validation.Extensions Assembly: ReactiveUI.Validation.dll

Applies to

net10.0, net10.0-tvos26.0, net10.0-maccatalyst26.0, net10.0-browserwasm1.0, net10.0-desktop1.0, net10.0-macos26.0, net10.0-windows10.0.19041, net10.0-ios26.0, net10.0-android36.0, net9.0, net9.0-windows10.0.19041, net9.0-browserwasm1.0, net9.0-desktop1.0, net8.0, net8.0-macos14.2, net8.0-maccatalyst17.5, net8.0-ios17.5, net8.0-tvos17.2, net8.0-windows10.0.19041, net8.0-macos14.5, netstandard2.1, net481, net462, net471

Overloads¶

1. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp?>> viewModelProperty, Func<TViewModelProp?, bool> isPropertyValid, string message) where TViewModel : IReactiveObject, IValidatableViewModel
2. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp?>> viewModelProperty, Func<TViewModelProp?, bool> isPropertyValid, Func<TViewModelProp?, string> message) where TViewModel : IReactiveObject, IValidatableViewModel
3. public static ValidationHelper ValidationRule<TViewModel>(this TViewModel viewModel, IObservable<bool> validationObservable, string message) where TViewModel : IReactiveObject, IValidatableViewModel
4. public static ValidationHelper ValidationRule<TViewModel, TValue>(this TViewModel viewModel, IObservable<TValue> validationObservable, Func<TValue, bool> isValidFunc, Func<TValue, string> messageFunc) where TViewModel : IReactiveObject, IValidatableViewModel
5. public static ValidationHelper ValidationRule<TViewModel>(this TViewModel viewModel, IObservable<IValidationState> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel
6. public static ValidationHelper ValidationRule<TViewModel, TValue>(this TViewModel viewModel, IObservable<TValue> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel where TValue : IValidationState
7. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<bool> viewModelObservable, string message) where TViewModel : IReactiveObject, IValidatableViewModel
8. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp, TValue>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<TValue> viewModelObservable, Func<TValue, bool> isValidFunc, Func<TValue, string> messageFunc) where TViewModel : IReactiveObject, IValidatableViewModel
9. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<IValidationState> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel
10. public static ValidationHelper ValidationRule<TViewModel, TViewModelProp, TValue>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<TValue> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel where TValue : IValidationState

1. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp?>> viewModelProperty, Func<TViewModelProp?, bool> isPropertyValid, string message) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule for a specified ViewModel property with static error message.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property.
`isPropertyValid`	Func	Func to define if the viewModelProperty is valid or not.
`message`	string	Validation error message.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, `isPropertyValid`, or `message` is null or empty.

2. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp?>> viewModelProperty, Func<TViewModelProp?, bool> isPropertyValid, Func<TViewModelProp?, string> message) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule for a specified ViewModel property with dynamic error message.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property.
`isPropertyValid`	Func	Func to define if the viewModelProperty is valid or not.
`message`	Func	Func to define the validation error message based on the viewModelProperty value.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, `isPropertyValid`, or `message` is null.

3. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel>(this TViewModel viewModel, IObservable<bool> validationObservable, string message) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable indicating validity and a static error message.

Type parameters

Name	Description
`TViewModel`	ViewModel type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.
`message`	string	Validation error message.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `validationObservable`, or `message` is null.

4. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TValue>(this TViewModel viewModel, IObservable<TValue> validationObservable, Func<TValue, bool> isValidFunc, Func<TValue, string> messageFunc) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable indicating validity with a dynamic validation function and a dynamic context-aware error message.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TValue`	Validation observable type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.
`isValidFunc`	Func	Func to define if the value emitted by the observable is valid.
`messageFunc`	Func	Func to define the validation error message based on the observable value.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `validationObservable`, `isValidFunc`, or `messageFunc` is null.

5. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel>(this TViewModel viewModel, IObservable<IValidationState> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable based on IValidationState.

Type parameters

Name	Description
`TViewModel`	ViewModel type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel` or `validationObservable` is null.

6. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TValue>(this TViewModel viewModel, IObservable<TValue> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel where TValue : IValidationState

View source

Summary: Setup a validation rule with a general observable based on IValidationState.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TValue`	Validation observable type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel` or `validationObservable` is null.

7. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<bool> viewModelObservable, string message) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable indicating validity and a static error message for the given view model property.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property referenced in viewModelObservableProperty.
`viewModelObservable`	IObservable	Observable to define if the viewModel is valid or not.
`message`	string	Validation error message.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, `viewModelObservable`, or `message` is null.

8. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp, TValue>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<TValue> viewModelObservable, Func<TValue, bool> isValidFunc, Func<TValue, string> messageFunc) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable indicating validity with a dynamic validation function and a dynamic context-aware error message for the given view model property.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.
`TValue`	Validation observable type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property referenced in viewModelObservableProperty.
`viewModelObservable`	IObservable	Observable to define if the viewModel is valid or not.
`isValidFunc`	Func	Func to define if the value emitted by the observable is valid.
`messageFunc`	Func	Func to define the validation error message based on the observable value.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, `viewModelObservable`, `isValidFunc`, or `messageFunc` is null.

9. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<IValidationState> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel

View source

Summary: Setup a validation rule with a general observable based on IValidationState.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property referenced in viewModelObservableProperty.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, or `validationObservable` is null.

10. Overload¶

Attributes: [RequiresDynamicCode("WhenAnyValue uses expression trees which require dynamic code generation in AOT scenarios.")] [RequiresUnreferencedCode("WhenAnyValue may reference members that could be trimmed in AOT scenarios.")]

public static ValidationHelper ValidationRule<TViewModel, TViewModelProp, TValue>(this TViewModel viewModel, Expression<Func<TViewModel, TViewModelProp>> viewModelProperty, IObservable<TValue> validationObservable) where TViewModel : IReactiveObject, IValidatableViewModel where TValue : IValidationState

View source

Summary: Setup a validation rule with a general observable based on IValidationState.

Type parameters

Name	Description
`TViewModel`	ViewModel type.
`TViewModelProp`	ViewModel property type.
`TValue`	Validation observable type.

Parameters

Name	Type	Description
`viewModel`	`TViewModel`	ViewModel instance.
`viewModelProperty`	Expression>	ViewModel property referenced in viewModelObservableProperty.
`validationObservable`	IObservable	Observable to define if the viewModel is valid or not.

Returns: ValidationHelper -- Returns a ValidationHelper object.

Remarks

        It should be noted that the observable should provide an initial value, otherwise that can result
        in an inconsistent performance.

Exceptions

Type	Condition
System.ArgumentNullException	Thrown when `viewModel`, `viewModelProperty`, or `validationObservable` is null.