I am looking at implementing some pretty simple client side validation by implementing the IClientModelValidator interface. Specifically I am creating a NotEqualTo (and later an EqualTo) validation attribute that will compare the value of one input to another.
To provide a nice UX I want to use the display name of both inputs in the error messages: "Password cannot be the same as Email" for example.
This is has obviously been done a million times and there are plenty of example around, but they are either for previous versions of MVC or are not using the display name of the other property.
Below is what I have so far. I have managed to grab the display name via the Display attribute in the server side IsValid(...) method, but I can't work out how to do similar for the client side AddValidation(...) method.
[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class NotEqualToAttribute : ValidationAttribute, IClientModelValidator
{
private const string defaultErrorMessage = "{0} cannot be the same as {1}.";
public string OtherProperty { get; private set; }
public NotEqualToAttribute(string otherProperty) : base(defaultErrorMessage)
{
this.OtherProperty = otherProperty;
}
public override string FormatErrorMessage(string name)
{
string.Format(base.ErrorMessageString, name, this.OtherProperty);
}
public void AddValidation(ClientModelValidationContext context)
{
context.Attributes.Add("data-val", "true");
context.Attributes.Add("data-val-notequalto", this.FormatErrorMessage(context.ModelMetadata.GetDisplayName());
context.Attributes.Add("data-val-notequalto-otherproperty", this.otherProperty);
}
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
if (value == null)
return ValidationResult.Success;
PropertyInfo otherProperty = validationContext.ObjectInstance.GetType().GetProperty(this.OtherProperty);
object otherValue = otherProperty.GetValue(validationContext.ObjectInstance, null);
if (!value.Equals(otherValue))
return ValidationResult.Success;
DisplayAttribute display = otherProperty.GetCustomAttribute<DisplayAttribute>();
string otherName = display?.GetName() ?? this.OtherProperty;
return new ValidationResult(string.Format(defaultErrorMessage, validationContext.DisplayName, otherName));
}
}
Typically I solved this myself after taking a break, just going to leave this here in case it helps someone else (or there is a better solution):
public void AddValidation(ClientModelValidationContext context)
{
context.Attributes.Add("data-val", "true");
string otherName =
context.ModelMetadata.ContainerMetadata.Properties
.Single(p => p.PropertyName == this.OtherProperty)
.GetDisplayName();
context.Attributes.Add("data-val-notequalto",
string.Format(defaultErrorMessage, context.ModelMetadata.GetDisplayName(), otherName)
);
}
You can get to the meta data for the other properties via ClientModelValidationContext.ModelMetadata.ContainerMetadata.Properties
Related
I want to implement localization in a custom attribute to check if the property is a valid IP address or hostname. The validation is working fine so far, but my problem is that I only get the default english error message though my local is switched to german. I am working with resource files. I do not want to implement a client side validation for this. I know there is way to implement an Adapter but correct me if I'm wrong, this is only for client side validation.
My custom validation class:
public class IPAddressOrHostnameAttribute : ValidationAttribute
{
public IPAddressOrHostnameAttribute(string propertyName, object desiredvalue, string errorMessage)
{
PropertyName = propertyName;
DesiredValue = desiredvalue;
ErrorMessage = errorMessage;
}
private string PropertyName { get; }
private object DesiredValue { get; }
protected override ValidationResult IsValid(object value, ValidationContext context)
{
var instance = context.ObjectInstance;
var type = instance.GetType();
var propertyValue = type.GetProperty(PropertyName).GetValue(instance, null);
if (propertyValue.ToString() == DesiredValue.ToString() && value != null)
{
if (Regex.IsMatch(value.ToString(), AckConstants.VALIDIPADDRESSREGEX)
|| Regex.IsMatch(value.ToString(), AckConstants.VALIDHOSTNAMEREGEX))
{
return ValidationResult.Success;
}
return new ValidationResult(ErrorMessage);
}
return ValidationResult.Success;
}
}
My model class:
[Required(ErrorMessage = "The field {0} is required")]
[RegularExpression(#"^\S*$", ErrorMessage = "No white spaces allowed.")]
[IPAddressOrHostname(nameof(IsFileAdapter), true, "Please enter a valid IP address or hostname")]
[IPAddress(nameof(IsFileAdapter), false, "Please enter a valid IP address")]
[Display(Name = "Destination")]
public string Destination { get; set; }
My startup class to configure the DataAnnotationLocalizerProvider:
services
.AddMvc()
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix,
opts => { opts.ResourcesPath = "Resources"; })
.AddDataAnnotationsLocalization(options =>
{
options.DataAnnotationLocalizerProvider = (type, factory) =>
factory.Create(typeof(SharedResource)); // SharedResource is the class where the DataAnnotations (translations) will be stored.
})
The localization is working for the default attributes like e.g. Required etc. but not for my custom validation attribute. I have no idea what's wrong in my code. I have read the stackoverflow post ASP.NET Core custom validation attribute localization, but I do not understand why my server side validation with localization is not working. Hopefully someone can help me or give me an example how to get it work, because this problem is driving me crazy.
Creating an adapter could be a solution, but it is too expensive! you have to create the adapter, then create adapter provider then you need to register it in startup! it is too much work.
A shorter solution is to get localization service in the custom validation attribute via ValidationContext.GetService:
If you are using the built-in localization service it will be IStringLocalizer, if you are using a custom localization service e.g. (MyLocalizer) you can access it by parsing it to the GetService(typeof(MyLocalizer)) method. see below sample:
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
var _localizationService = (IStringLocalizer)validationContext.GetService(typeof(IStringLocalizer));
var localizedError = _localizationService[ErrorMessage];
//
// do your custom validation
//
// if validation result is wrong
return new ValidationResult(localizedError);
// if validation result is correct
return ValidationResult.Success;
}
btw, ValidationAttribute already has ErrorMessage property, so you don't have to define it in your custom attribute.
public IPAddressOrHostnameAttribute(string propertyName, object desiredvalue /*, string errorMessage*/)
{
PropertyName = propertyName;
DesiredValue = desiredvalue;
// ErrorMessage = errorMessage;
}
Use it just like other attributes:
[IPAddressOrHostname(nameof(IsFileAdapter), true, ErrorMessage = "Please enter a valid IP address or hostname")]
I do not want to implement a client side validation for this. I know there is way to implement an Adapter but correct me if I'm wrong, this is only for client side validation.
Actually, that's not the truth. Adapter doesn't means you'll have to use a client side validation. Please see Ramin's answer here.
As for your question itself, you could create an Adapter and also a AdapterProvider to provide a adapter:
public class IPAddressOrHostnameAttributeAdapter : AttributeAdapterBase<IPAddressOrHostnameAttribute>
{
public IPAddressOrHostnameAttributeAdapter(IPAddressOrHostnameAttribute attribute, IStringLocalizer stringLocalizer)
: base(attribute, stringLocalizer)
{ }
public override void AddValidation(ClientModelValidationContext context) { }
public override string GetErrorMessage(ModelValidationContextBase validationContext)
{
return GetErrorMessage(validationContext.ModelMetadata, validationContext.ModelMetadata.GetDisplayName());
}
}
public class IPAddressOrHostnameAttributeAdapterProvider : IValidationAttributeAdapterProvider
{
private readonly IValidationAttributeAdapterProvider fallback = new ValidationAttributeAdapterProvider();
public IAttributeAdapter GetAttributeAdapter(ValidationAttribute attribute, IStringLocalizer stringLocalizer)
{
var attr = attribute as IPAddressOrHostnameAttribute;
return attr == null?
this.fallback.GetAttributeAdapter(attribute, stringLocalizer):
new IPAddressOrHostnameAttributeAdapter(attr, stringLocalizer);
}
}
Also, ensure this service is registered in the DI container:
services.AddSingleton<IValidationAttributeAdapterProvider, IPAddressOrHostnameAttributeAdapterProvider>();
Finally, if you're using querystring as the culture provider, don't forget to append a culture=de in your form action:
#{ var __culture = Context.Features.Get<IRequestCultureFeature>().RequestCulture.Culture.ToString(); }
<form asp-action="Create" asp-route-culture="#__culture">
....
</form>
A Screenshot of the Demo
I'm having a problem trying to get custom model binders to work as a query parameter like I have gotten to work previously in .net framework 4.7.
To ensure this wasn't a scenario where my object was too complex, I reduced the model to a simple string but even then I cannot get this to work.
I have a simple model I would like to be binded from query parameters.
public class SearchModel {
public string SearchTerms { get; set; }
}
And I have configured the ModelBinder and ModelBinderProvider as shown here like so.
public class TestModelBinder : IModelBinder {
public Task BindModelAsync(ModelBindingContext bindingContext) {
if (bindingContext.ModelType != typeof(SearchModel)) {
throw new ArgumentException($"Invalid binding context supplied {bindingContext.ModelType}");
}
var model = (SearchModel)bindingContext.Model ?? new SearchModel();
var properties = model.GetType().GetProperties();
foreach(var p in properties) {
var value = this.GetValue(bindingContext, p.Name);
p.SetValue(model, Convert.ChangeType(value, p.PropertyType), null);
}
return Task.CompletedTask;
}
protected string GetValue(ModelBindingContext context, string key) {
var result = context.ValueProvider.GetValue(key);
return result.FirstValue;
}
}
public class TestModelBinderProvider : IModelBinderProvider {
public IModelBinder GetBinder(ModelBinderProviderContext context) {
if (context == null) {
throw new ArgumentNullException(nameof(context));
}
if (context.Metadata.ModelType == typeof(SearchModel)) {
var returnType = new BinderTypeModelBinder(typeof(TestModelBinder));
return returnType;
}
return null;
}
}
As stated in the last step in Microsoft documentation I updated my ConfigureServices method in Startup.cs to include the BinderProvider.
services.AddMvc(options => {
options.ModelBinderProviders.Insert(0, new TestModelBinderProvider());
})
.SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
But when I call my Search endpoint with a url such as "https://localhost:44387/api/testbinding?searchTerms=newSearch" I am always seeing a return of "request == null True" even though I see it properly hit the custom binding and bind correctly if I step through debugging, can anyone please point me in the right direction as to what I am doing wrong?
[Route("api/[controller]")]
[ApiController]
public class TestBindingController : ControllerBase {
[HttpGet()]
public IActionResult GetResult([FromQuery] SearchModel request) {
return Ok($"request == null {request == null}");
}
}
I think what you're missing if the statement that sets the result of the model binding operation, as you can see in the AuthorEntityBinder code sample in this section of the docs:
bindingContext.Result = ModelBindingResult.Success(model);
Your implementation of the model binder does create an instance of SearchModel, but doesn't feed it back to the model binding context.
As a separate note, I don't think you need to add a custom model binder is the query string segments match the properties names of the model you're trying to bind.
In ASP.Net MVC 5, custom data annotation validator can be implemented by inheriting DataAnnotationsModelValidator and registering using DataAnnotationsModelValidatorProvider.RegisterAdapter(...). In ASP.Net Core MVC, how can I achieve this?
I found similar question at ASP.net core MVC 6 Data Annotations separation of concerns, but can anyone show me simple example code?
It seems to me ASP.NET Core MVC does not have support for DataAnnotationsModelValidatorProvider.RegisterAdapter anymore. The solution I discovered is as follows:
Suppose I want to change the Validator for RequiredAttribute to my own validator adaptor (MyRequiredAttributeAdaptor), Change the default error message of EmailAddressAttribute, and change the Localized Error Message Source for 'CompareAttribute' to my own message.
1- Create a custom ValidationAttributeAdapterProvider
using Microsoft.AspNetCore.Mvc.DataAnnotations;
using Microsoft.AspNetCore.Mvc.DataAnnotations.Internal;
using Microsoft.Extensions.Localization;
using System.ComponentModel.DataAnnotations;
public class CustomValidationAttributeAdapterProvider
: ValidationAttributeAdapterProvider, IValidationAttributeAdapterProvider
{
public CustomValidationAttributeAdapterProvider() { }
IAttributeAdapter IValidationAttributeAdapterProvider.GetAttributeAdapter(
ValidationAttribute attribute,
IStringLocalizer stringLocalizer)
{
IAttributeAdapter adapter;
if (attribute is RequiredAttribute)
{
adapter = new MyRequiredAttributeAdaptor((RequiredAttribute) attribute, stringLocalizer);
}
else if (attribute is EmailAddressAttribute)
{
attribute.ErrorMessage = "Invalid Email Address.";
adapter = base.GetAttributeAdapter(attribute, stringLocalizer);
}
else if (attribute is CompareAttribute)
{
attribute.ErrorMessageResourceName = "InvalidCompare";
attribute.ErrorMessageResourceType = typeof(Resources.ValidationMessages);
var theNewattribute = attribute as CompareAttribute;
adapter = new CompareAttributeAdapter(theNewattribute, stringLocalizer);
}
else
{
adapter = base.GetAttributeAdapter(attribute, stringLocalizer);
}
return adapter;
}
}
2- Add the CustomValidationAttributeAdapterProvider to start up:
Add the following line to public void ConfigureServices(IServiceCollection services) in Startup.cs:
services.AddSingleton <IValidationAttributeAdapterProvider, CustomValidationAttributeAdapterProvider> ();
Here is MyRequiredAttributeAdaptor adaptor:
using System;
using System.ComponentModel.DataAnnotations;
using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
using Microsoft.Extensions.Localization;
using Microsoft.AspNetCore.Mvc.DataAnnotations.Internal;
public class MyRequiredAttributeAdaptor : AttributeAdapterBase<RequiredAttribute>
{
public MyRequiredAttributeAdaptor(RequiredAttribute attribute, IStringLocalizer stringLocalizer)
: base(attribute, stringLocalizer)
{
}
public override void AddValidation(ClientModelValidationContext context)
{
if (context == null)
{
throw new ArgumentNullException(nameof(context));
}
MergeAttribute(context.Attributes, "data-val", "true");
MergeAttribute(context.Attributes, "data-val-required", GetErrorMessage(context));
}
/// <inheritdoc />
public override string GetErrorMessage(ModelValidationContextBase validationContext)
{
if (validationContext == null)
{
throw new ArgumentNullException(nameof(validationContext));
}
return GetErrorMessage(validationContext.ModelMetadata, validationContext.ModelMetadata.GetDisplayName());
}
}
References:
1- See the example of Microsoft: Entropy project: This is a great sample for diffrent features of .NET Core. In this question: see the MinLengthSixAttribute implementation in the Mvc.LocalizationSample.Web sample:
https://github.com/aspnet/Entropy/tree/dev/samples/Mvc.LocalizationSample.Web
2- In order to see how the attribute adapters works see asp.Microsoft.AspNetCore.Mvc.DataAnnotations on github:
https://github.com/aspnet/Mvc/tree/master/src/Microsoft.AspNetCore.Mvc.DataAnnotations
To define a custom validator by a annotation you can define your own class that derives from ValidationAttribute and override the IsValid method. There is no need to register this class explicitly.
In this example a custom validation attribute is used to accept only odd numbers as valid values.
public class MyModel
{
[OddNumber]
public int Number { get; set; }
}
public class OddNumberAttribute : ValidationAttribute
{
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
try
{
var number = (int) value;
if (number % 2 == 1)
return ValidationResult.Success;
else
return new ValidationResult("Only odd numbers are valid.");
}
catch (Exception)
{
return new ValidationResult("Not a number.");
}
}
}
A second approach is that the Model class implements IValidatableObject. This is especially useful, if validation requires access to multiple members of the model class. Here is the second version of the odd number validator:
public class MyModel : IValidatableObject
{
public int Number { get; set; }
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
{
if (Number % 2 == 0)
yield return new ValidationResult(
"Only odd numbers are valid.",
new [] {"Number"});
}
}
You can find more information about custom validation in https://docs.asp.net/en/latest/mvc/models/validation.html#custom-validation.
This is a followup to the question here, where the answer seems to refer to an overly-complicated and overly-specific (EF, which I'm not using - not even using an ORM).
There has to be a more straightforward way around this common scenario than the smoke, mirrors, and sorcery hinted at in that answer.
Note: I encased "context" in parenthesis because I'm not using EF, so it is not a literal "dbcontext" that I'm talking about here.
So I got to wondering: Could I set a global variable for each session when the user is authenticated and authorized?
e.g., when the user is authenticated/authorized, I would know which database context/contents should be served up to him.
So it seems I could set a value in Global.asax.cs' Application_Start() method and then either alter the RepositoriesInstaller (implementing IWindsorInstaller) class to conditionally register different concrete Repositories based on the user and what data he should have OR place conditional code in the concrete Repository itself to use this or that database instance.
Is this feasible? Is one way (altering the RepositoriesInstaller / altering the concrete Repositories class) preferred?
Have a look at this answer which will show you how to resolve the correct repository based on a key or value.
If you want to store it with the authorized user, you need to simple serialize the data and store it on the authenticated cookie:
Create a Model to represent the logged in information:
public class AuthenticatedMember
{
public Guid Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public int SiteNumber { get; set; }
}
Do something like a login in your controller:
var authenticatedMember = MembershipManager.ValidateLogin(model.Email, model.Password);
var cookie = FormsAuthentication.GetAuthCookie(authenticatedMember.Id.ToString(), false);
var ticket = FormsAuthentication.Decrypt(cookie.Value);
var newTicket = new FormsAuthenticationTicket(ticket.Version, ticket.Name, ticket.IssueDate, ticket.Expiration, ticket.IsPersistent, authenticatedMember.ToJson(), ticket.CookiePath);
cookie.Value = FormsAuthentication.Encrypt(newTicket);
Response.Cookies.Add(cookie);
Then use a model binder to deserialize the AuthenticatedMember when you require:
public class AuthenticatedMemberModelBinder : IModelBinder
{
#region IModelBinder Members
public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
if (bindingContext.Model != null)
{
throw new InvalidOperationException("Cannot update instances");
}
if (controllerContext.RequestContext.HttpContext.Request.IsAuthenticated)
{
var cookie = controllerContext
.RequestContext
.HttpContext
.Request
.Cookies[FormsAuthentication.FormsCookieName];
if (null == cookie)
return null;
var decrypted = FormsAuthentication.Decrypt(cookie.Value);
if (!string.IsNullOrEmpty(decrypted.UserData))
{
return JsonConvert.DeserializeObject<AuthenticatedMember>(decrypted.UserData);
}
}
return null;
}
#endregion
}
I want to create a composite Windows Workflow Activity (under .NET 4) that contains a predefined ReceiveAndSendReply Activity. Some of the properties are predefined, but others (particularly ServiceContractName) need to be set in the designer.
I could implement this as an Activity Template (the same way ReceiveAndSendReply is implemented), but would rather not. If I later change the template, I'd have to update all previously created workflows manually. A template would also permit other developers to change properties that should be fixed.
Is there a way to do this from a Xaml Activity? I have not found a way to assign an Argument value to a property of an embedded Activity. If not, what technique would you suggest?
I haven't done this using a composite XAML activity and am getting some errors when I try but doing so through a NativeActivity is no problem. See the example code below.
public class MyReceiveAndSendReply : NativeActivity
{
private Receive _receive;
private SendReply _sendReply;
public string ServiceContractName { get; set; }
public string OperationName { get; set; }
protected override bool CanInduceIdle
{
get { return true; }
}
protected override void CacheMetadata(NativeActivityMetadata metadata)
{
_receive = _receive ?? new Receive();
_sendReply = _sendReply ?? new SendReply();
_receive.CanCreateInstance = true;
metadata.AddImplementationChild(_receive);
metadata.AddImplementationChild(_sendReply);
_receive.ServiceContractName = ServiceContractName;
_receive.OperationName = OperationName;
var args = new ReceiveParametersContent();
args.Parameters["firstName"] = new OutArgument<string>();
_receive.Content = args;
_sendReply.Request = _receive;
var results = new SendParametersContent();
results.Parameters["greeting"] = new InArgument<string>("Hello there");
_sendReply.Content = results;
base.CacheMetadata(metadata);
}
protected override void Execute(NativeActivityContext context)
{
context.ScheduleActivity(_receive, ReceiveCompleted);
}
private void ReceiveCompleted(NativeActivityContext context, ActivityInstance completedInstance)
{
context.ScheduleActivity(_sendReply);
}
}