public ValidationViewModel()
{
// null is success(have no error), string is error message
ValidationData = new ReactiveProperty <string>()
.SetValidateNotifyError((string s) => !string.IsNullOrEmpty(s) && s.Cast <char>().All(Char.IsUpper) ? null : "not all uppercase");
// async validation
// first argument is self observable sequence
// null is success(have no error), IEnumerable is error messages
ValidationNotify = new ReactiveProperty <string>("foo!", ReactivePropertyMode.RaiseLatestValueOnSubscribe)
.SetValidateNotifyError(self => self
.Delay(TimeSpan.FromSeconds(3)) // asynchronous validation...
.Select(s => string.IsNullOrEmpty(s) ? null : "not empty string"));
// both validation
ValidationBoth = new ReactiveProperty <string>()
.SetValidateNotifyError(s => !string.IsNullOrEmpty(s) && s.Cast <char>().All(Char.IsLower) ? null : "not all lowercase")
.SetValidateNotifyError(self => self
.Delay(TimeSpan.FromSeconds(1)) // asynchronous validation...
.Select(s => string.IsNullOrEmpty(s) || s.Length <= 5 ? null : (IEnumerable) new[] { "length 5" }));
// Validation result is pushed to ObserveErrors
var errors = new[]
{
ValidationData.ObserveErrorChanged,
ValidationBoth.ObserveErrorChanged,
ValidationNotify.ObserveErrorChanged
}
.CombineLatest();
// Use OfType, choose error source
ErrorInfo = errors
.SelectMany(x => x)
.Where(x => x != null)
.Select(x => x.OfType <string>())
.Select(x => x.FirstOrDefault())
.ToReactiveProperty();
// Validation is view initialized not run in default.
// If want to validate on view initialize,
// use ReactivePropertyMode.RaiseLatestValueOnSubscribe to ReactiveProperty
// that mode is validate values on initialize.
NextCommand =
new[]
{
ValidationData.ObserveHasErrors,
ValidationBoth.ObserveHasErrors,
ValidationNotify.ObserveHasErrors
}
.CombineLatestValuesAreAllFalse()
.ToReactiveCommand();
this.AlertMessage = NextCommand.Select(_ => "Can go to next!").ToReactiveProperty(
initialValue: "Can go to next!",
mode: ReactivePropertyMode.None);
}
public ValidationViewModel()
{
// IDataErrorInfo, call SetValidateError and set validate condition
// null is success(have no error), string is error message
ValidationData = new ReactiveProperty <string>()
.SetValidateNotifyError((string s) => !string.IsNullOrEmpty(s) && s.Cast <char>().All(Char.IsUpper) ? null : "not all uppercase");
// INotifyDataErrorInfo, call SetValidateNotifyErro and set validate condition
// first argument is self observable sequence
// null is success(have no error), IEnumerable is error messages
ValidationNotify = new ReactiveProperty <string>("foo!", ReactivePropertyMode.RaiseLatestValueOnSubscribe)
.SetValidateNotifyError(self => self
.Delay(TimeSpan.FromSeconds(3)) // asynchronous validation...
.Select(s => string.IsNullOrEmpty(s) ? null : (IEnumerable) new[] { "not empty string" }));
// Can set both validation
ValidationBoth = new ReactiveProperty <string>()
.SetValidateNotifyError((string s) => !string.IsNullOrEmpty(s) && s.Cast <char>().All(Char.IsLower) ? null : "not all lowercase")
.SetValidateNotifyError(self => self
.Delay(TimeSpan.FromSeconds(1)) // asynchronous validation...
.Select(s => string.IsNullOrEmpty(s) || s.Length <= 5 ? null : (IEnumerable) new[] { "length 5" }));
// Validation result is pushed to ObserveErrorChanged
var errors = Observable.Merge(
ValidationData.ObserveErrorChanged,
ValidationBoth.ObserveErrorChanged,
ValidationNotify.ObserveErrorChanged);
// Use OfType, choose error source
ErrorInfo = Observable.Merge(
errors.Where(o => o == null).Select(_ => ""), // success
errors.OfType <string>(), // from IDataErrorInfo
errors.OfType <string[]>().Select(xs => xs[0])) // from INotifyDataErrorInfo
.ToReactiveProperty();
// Validation is view initialized not run in default.
// If want to validate on view initialize,
// use ReactivePropertyMode.RaiseLatestValueOnSubscribe to ReactiveProperty
// that mode is validate values on initialize.
NextCommand = ValidationData.ObserveErrorChanged
.CombineLatest(
ValidationBoth.ObserveErrorChanged,
ValidationNotify.ObserveErrorChanged,
(a, b, c) => new[] { a, b, c }.All(x => x == null))
.ToReactiveCommand(initialValue: false);
this.AlertMessage = NextCommand.Select(_ => "Can go to next!").ToReactiveProperty(
initialValue: "Can go to next!",
mode: ReactivePropertyMode.None);
}