I have the following class used for custom validation:
[AttributeUsage(AttributeTargets.Property, AllowMultiple=false, Inherited=true)]
public sealed class RequiredIfAnyTrueAttribute : ValidationAttribute, IClientValidatable
{
private const string DefaultErrorMessage = "{0} is required";
public List<string> OtherProperties { get; private set; }
public RequiredIfAnyTrueAttribute(string otherProperties)
: base(DefaultErrorMessage)
{
if (string.IsNullOrEmpty(otherProperties))
throw new ArgumentNullException("otherProperty");
OtherProperties = new List<string>(otherProperties.Split(new char[] { '|', ',' }));
}
public override string FormatErrorMessage(string name)
{
return string.Format(ErrorMessageString, name);
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
if (value == null)
{
foreach (string s in OtherProperties)
{
var otherProperty = validationContext.ObjectType.GetProperty(s);
var otherPropertyValue = otherProperty.GetValue(validationContext.ObjectInstance, null);
if (otherPropertyValue.Equals(true))
return new ValidationResult(FormatErrorMessage(validationContext.DisplayName));
}
}
return ValidationResult.Success;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context)
{
var clientValidationRule = new ModelClientValidationRule()
{
ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()),
ValidationType = "requiredifanytrue"
};
clientValidationRule.ValidationParameters.Add("otherproperties", string.Join("|",OtherProperties));
return new[] { clientValidationRule };
}
}
My ViewModel is:
public class SampleViewModel
{
public bool PropABC { get; set; }
public bool PropXYZ { get; set; }
[RequiredIfAnyTrue("PropABC|PropXYZ")]
public int? TestField { get; set; }
}
When my strongly typed view renders, everything sees to work fine. If PropABC or PropXYZ is selected then I am required to enter a value for TestField. Both client and server-side validation is functional.
However, given the following sequence of events:
check PropABC
submit form
client-side validation fires for TestField required
uncheck PropABC
client validation does not re-fire and validation message
remains until form submit
In order to resolve #5 I would typically attach click events to the checkboxes via jquery onready to refire the validation.
Is there a preferred/recommended way to manually force client-side validation given MVC3 + unobstrusive + jquery?
Shawn, attaching to events is the best approach to get validation to refire.
I would suggest creating a class called "validate" (or something along those lines), adding it to each element to be validated, and then use jQuery to attach to the click and blur events (and possibly the change event) of each element with that class, and validate the element like so:
$("form").validate().element(this);
Do you need to write your own attributes? If not I think you may be able to avoid "reinventing the wheel"
FoolProof works great. you get get it as a NuGet package.
NuGet: install-package foolproof
It includes a lot of greate attributes for various combinations of on-the-fly required fields and such.
FoolProof is still in beta and does not work with nested viewmodel, also with arrays
Related
I have a new Xamarin Forms 5 app and I'm having trouble with data binding.
First, I display a message that tells the user how many items are in his list. Initially, this is 0. It's displayed by DisplayMessage property of the view model.
Then, the Init() method gets called and once the API call is finished, there are some items in MyList. I put break points to make sure that the API call works and I end up with some data in MyList property.
Because I change the value of message in my Init() method, I was expecting the message to change and display the number of items in the list but it's not changing even though I have some items in MyList.
I created a new ViewModel that looks like this:
public class MyViewModel : BaseViewModel
{
public List<MyItem> MyList { get; set; } = new List<MyItem>();
string message = "You have no items in your list... ";
public string DisplayMessage
{
get => message;
set
{
if(message == value)
return;
message = value;
OnPropertyChanged();
}
}
public async void Init()
{
var data = await _myService.GetData();
if(data.Count > 0)
message = $"You have {data.Count} items in your list!";
MyList = data;
}
}
My MainPage code behind looks like this:
[XamlCompilation(XamlCompilationOptions.Compile)]
public partial class MainPage : ContentPage
{
MyViewModel _vm;
MainPage()
{
InitializeComponent();
_vm = new MyViewModel();
this.BindingContext = _vm;
}
protected override void OnAppearing()
{
base.OnAppearing();
_vm.Init();
}
}
I didn't change anyting in the base view model, except I added my service and it looks like this:
public class BaseViewModel : INotifyPropertyChanged
{
public IMyApiService MyApi => DependencyService.Get<IMyApiService>();
bool isBusy = false;
public bool IsBusy
{
get { return isBusy; }
set { SetProperty(ref isBusy, value); }
}
string title = string.Empty;
public string Title
{
get { return title; }
set { SetProperty(ref title, value); }
}
protected bool SetProperty<T>(ref T backingStore, T value,
[CallerMemberName] string propertyName = "",
Action onChanged = null)
{
if (EqualityComparer<T>.Default.Equals(backingStore, value))
return false;
backingStore = value;
onChanged?.Invoke();
OnPropertyChanged(propertyName);
return true;
}
#region INotifyPropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
{
var changed = PropertyChanged;
if (changed == null)
return;
changed.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
#endregion
}
I'd appreciatae someone telling me where my mistake is. Thanks.
Without seeing the Xaml, I can't 100% answer, but here are a couple of things I see:
You are setting the "message" through the field, not the property. Since you are setting the field directly the OnPropertyChanged event isn't firing so the UI isn't getting notified that the value has changed.
I am guessing you are binding "MyList" to some sort of CollectionView or something? If it's a readonly view, using a List is ok as the collection is never updated. However, if you plan on adding or removing items at runtime, it needs to be an "ObservableCollection" for the same reason as above, the UI isn't notified of new items in a List, but an ObservableCollection will notify the UI of changes to it, so it can update.
Is what Jason mentions above in his comment. The MyList property should be setup like the other properties with the OnPropertyChanged.
I am using shell and I want tabs on all the pages. so I am following standard way of shell navigation but the problem is I don't know how to pass an object along with the navigation.
await Shell.Current.GoToAsync(page.ToString());
doing this for navigation
Routing.RegisterRoute("TesProject.Views.DetailView", typeof(DetailView));
Registering Route like this
I want to pass a complete object from my list view to detail view. How can I do that?
Xamarin.Forms Shell Navigation Hierarchy with parameters
I saw this but I don't think this will work in my case because I can't pass a complete model object like this.
I wrote a small example for your reference.
In the sending class, you can pass parameters like $"AferPage?param={param}".
Here is the sending code:
public partial class BeforePage : ContentPage
{
public BeforePage()
{
InitializeComponent();
}
private async void Button_Clicked(object sender, EventArgs e)
{
string param = myEntry.Text;
await Shell.Current.GoToAsync($"AferPage?param={param}");//like this
}
}
Here is the receiving class code(Implements IQueryAttributable interface):
public partial class AferPage : ContentPage, IQueryAttributable
{
public string param {get;set;}
public void ApplyQueryAttributes(IDictionary<string, string> query)
{
param = HttpUtility.UrlDecode(query["param"]);
receive.Text = param;
}
public AferPage()
{
InitializeComponent();
}
}
Using Newtonsoft.Json you can:
In List View:
var jsonStr = JsonConvert.SerializeObject([Model]);
await Shell.Current.GoToAsync($"{nameof([DetailsViewPage])}?Param={jsonStr }");
In Details View Page:
Add QueryProperty:
[QueryProperty(nameof(Param), nameof(Param))]
Convert to Model again:
var bonusesFilterData = JsonConvert.DeserializeObject<[Model]>(Param);
A solution is shown in this video: https://www.youtube.com/watch?v=YwnEpiJd0I8
You can pass objects through as a Dictionary.
For example if this is the data object you want to send:
public class Person
{
public string Name { get; set; }
public int Age { get; set; }
}
Set the query property on the view model of the page:
[QueryProperty(nameof(Person), nameof(Person))]
public partial class DetailViewModel
{
[ObservableProperty]
Person person;
}
Assuming your page constructor looks something like this so it will automatically set the value on your context:
public partial class DetailView : ContentPage
{
public DetailView(DetailViewModel vm)
{
InitializeComponent();
BindingContext = vm;
}
Then when you navigate to the page, pass the object in a dictionary:
Routing.RegisterRoute(nameof(DetailView), typeof(DetailView));
await Shell.Current.GoToAsync(nameof(DetailView), {
new Dictionary<string, object> {
[nameof(Person)] = person
});
Now you can access your object in bindings:
<Label Text="{Binding Person.Name}"/>
<Label Text="{Binding Person.Age}"/>
P.S. Notice the use of nameof to avoid hard coded strings.
You can user stored preferences if your json is complex like:
private async void OnItemSelected(Item item)
{
if (item == null)
return;
var jsonstr = JsonConvert.SerializeObject(item);
//Clear the shared preferences in case there is any
Preferences.Clear();
//Store your complex json on a shared preference
Preferences.Set("Data", jsonstr);
await Shell.Current.GoToAsync(nameof(DetailsPage));
}
On the details page where you retrieve your data you can have the following code:
bool hasKey = Preferences.ContainsKey("Data");
var content = Preferences.Get("Data", string.Empty);
Details details = hasKey ? JsonConvert.DeserializeObject<Model>(content) : null;
I am looking into this New EmailAddressAttribute part of their source code here. Code look like as follows. I am just wondering if there should be any client side script provided with it as this class implements IClientValidatable interface as well.
public sealed class EmailAddressAttribute : DataTypeAttribute, IClientValidatable {
private static Regex _regex = new Regex(#"^([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+(\.([a-z]|\d|[!#\$%&'\*\+\-\/=\?\^_`{\|}~]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])+)*)|((\x22)((((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(([\x01-\x08\x0b\x0c\x0e-\x1f\x7f]|\x21|[\x23-\x5b]|[\x5d-\x7e]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(\\([\x01-\x09\x0b\x0c\x0d-\x7f]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF]))))*(((\x20|\x09)*(\x0d\x0a))?(\x20|\x09)+)?(\x22)))#((([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|\d|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.)+(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])|(([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])([a-z]|\d|-|\.|_|~|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])*([a-z]|[\u00A0-\uD7FF\uF900-\uFDCF\uFDF0-\uFFEF])))\.?$", RegexOptions.Compiled | RegexOptions.IgnoreCase);
public EmailAddressAttribute()
: base(DataType.EmailAddress) {
ErrorMessage = MvcResources.EmailAddressAttribute_Invalid;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) {
yield return new ModelClientValidationRule {
ValidationType = "email",
ErrorMessage = FormatErrorMessage(metadata.GetDisplayName())
};
}
public override bool IsValid(object value) {
if (value == null) {
return true;
}
string valueAsString = value as string;
return valueAsString != null && _regex.Match(valueAsString).Length > 0;
}
}
}
Client validation is done unobtrusively based on html5 attributes that are attached to the element being validated (i.e. <input type="text" data-val-required="The field is required." />).
The java-script is in a static library and is based on jquery validate.
This is my model.
public class MyModel
{
[Display(Name = "Email Address")]
[EmailAddress] // my custom validator to check valid email format
[Remote("IsEmailAddressUsed", "Validation")]
public string EmailAddress { get; set; }
}
The problem I have is that the IsEmailAddressUsed action gets called even when I enter an invalid format for email address. The custom EmailAddress validator works fine when I remove the Remote one. I want to check against the DB only when the email address is in a correct format. Is there a way to make the Remote validator evaluated last?
The implementation of the custom validator: EmailAddressAttribute.
public class EmailAddressAttribute : RegularExpressionAttribute, IClientValidatable
{
public EmailAddressAttribute() :
base("^[a-z0-9_\\+-]+(\\.[a-z0-9_\\+-]+)*#[a-z0-9]+(\\.[a-z0-9]+)*\\.([a-z]{2,4})$")
{
}
protected override ValidationResult IsValid(object value,
ValidationContext validationContext)
{
if (value != null)
{
if (!base.IsValid(value))
{
return new ValidationResult(
FormatErrorMessage(validationContext.DisplayName));
}
}
return ValidationResult.Success;
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata,
ControllerContext context)
{
var rule = new ModelClientValidationRule
{
ErrorMessage = FormatErrorMessage(metadata.GetDisplayName())
};
rule.ValidationParameters.Add("pattern", Pattern);
rule.ValidationType = "emailaddress";
yield return rule;
}
}
And the accompanying script:
if ($.validator && $.validator.unobtrusive)
{
$.validator.unobtrusive.adapters.addSingleVal("emailaddress", "pattern");
$.validator.addMethod("emailaddress", function (value, element, pattern) {
return value.match(pattern);
});
}
Thanks!
My ORM (LightSpeed) generates this for Animals table, with Name and Age. Using MVC3 and Razor
[Serializable]
[System.CodeDom.Compiler.GeneratedCode("LightSpeedModelGenerator", "1.0.0.0")]
[System.ComponentModel.DataObject]
[Table(IdColumnName="AnimalID", IdentityMethod=IdentityMethod.IdentityColumn)]
public partial class Animal : Entity<int>
{
[ValidatePresence]
[ValidateLength(0, 50)]
private string _name;
[ValidateComparison(ComparisonOperator.GreaterThan, 0)]
private int _age;
public const string NameField = "Name";
public const string AgeField = "Age";
[System.Diagnostics.DebuggerNonUserCode]
[Required] // ****I put this in manually to get Name required working
public string Name
{
get { return Get(ref _name, "Name"); }
set { Set(ref _name, value, "Name"); }
}
[System.Diagnostics.DebuggerNonUserCode]
public int Age
{
get { return Get(ref _age, "Age"); }
set { Set(ref _age, value, "Age"); }
}
With [Required] attribute added:
With no [Required] attribute added: (notice LightSpeed strange rendering of validation)
With name filled in:
In images above - the validation at the top is LightSpeed (put into ValidationSummary) and at the side is MVC3 (put into ValidationMessageFor)
Am only using Server Side validation currently.
Question: How do I get LightSpeed validation working well in MVC3?
I think it is something in this area http://www.mindscapehq.com/staff/jeremy/index.php/2009/03/aspnet-mvc-part4/
For the server side validation - you will want to use a custom model binder which emits the errors from LightSpeed validation more precisely rather than the leveraging the DefaultModelBinder behavior. Have a look at either directly using or adapting the EntityModelBinder from the community code library for Mvc
http://www.mindscapehq.com/forums/Thread.aspx?PostID=12051
See link http://www.mindscapehq.com/forums/Thread.aspx?ThreadID=4093
Jeremys answer (Mindscape have great support!)
public class EntityModelBinder2 : DefaultModelBinder
{
public static void Register(Assembly assembly)
{
ModelBinders.Binders.Add(typeof(Entity), new EntityModelBinder2());
foreach (Type type in assembly.GetTypes())
{
if (typeof(Entity).IsAssignableFrom(type))
{
ModelBinders.Binders.Add(type, new EntityModelBinder2());
}
}
}
public override object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
object result = base.BindModel(controllerContext, bindingContext);
if (typeof(Entity).IsAssignableFrom(bindingContext.ModelType))
{
Entity entity = (Entity)result;
if (!entity.IsValid)
{
foreach (var state in bindingContext.ModelState.Where(s => s.Value.Errors.Count > 0))
{
state.Value.Errors.Clear();
}
foreach (var error in entity.Errors)
{
if (error.ErrorMessage.EndsWith("is invalid")) continue;
bindingContext.ModelState.AddModelError(error.PropertyName ?? "Custom", error.ErrorMessage);
}
}
}
return result;
}
}
and in Global.asax register using:
EntityModelBinder2.Register(typeof(MyEntity).Assembly);
The Register call sets up the model binder to be used for each entity type in your model assembly so modify as required.
You can get client side validation working with Lightspeed nightly builds from 04/04/2011 onwards.
Create a validator provider as follows:
public class LightspeedModelValidatorProvider : DataAnnotationsModelValidatorProvider
{
private string GetDisplayName(string name)
{
return name; // go whatever processing is required, eg decamelise, replace "_" with " " etc
}
protected override IEnumerable<ModelValidator> GetValidators(ModelMetadata metadata, ControllerContext context, IEnumerable<Attribute> attributes)
{
if(typeof(Entity).IsAssignableFrom(metadata.ContainerType))
{
List<Attribute> newAttributes = new List<Attribute>(attributes);
var attr = DataAnnotationBuilder.GetDataAnnotations(metadata.ContainerType, metadata.PropertyName, GetDisplayName(metadata.PropertyName));
newAttributes.AddRange(attr);
return base.GetValidators(metadata, context, newAttributes);
}
return base.GetValidators(metadata, context, attributes);
}
}
Then in Application_Start() add
ModelValidatorProviders.Providers.Clear();
ModelValidatorProviders.Providers.Add(new LightspeedModelValidatorProvider());