Has something changed with the rtm bits regarding the validation of models.
I have a simple viewmodel that looks like
public class ProductViewModel
{
[Required]
[DataMember(IsRequired = true)]
public int ProductTypeId { get; set; }
public string Product { get; set; }
}
(I just added the DataMember(IsRequired = true) as the error message I get says to use it to fix the problem. However no joy)
Within my controller the model state is telling me model is valid however when I try passing the model to my api using RestSharp I get the following error.
{"Message":"An error has occurred.","ExceptionMessage":"Property 'ProductTypeId' on type 'Mine.Model.Model' is invalid. Value-typed properties marked as [Required] must also be marked with [DataMember(IsRequired=true)] to be recognized as required. Consider attributing the declaring type with [DataContract] and the property with [DataMember(IsRequired=true)].","ExceptionType":"System.InvalidOperationException","StackTrace":" at System.Web.Http.Validation.Validators.ErrorModelValidator.Validate(ModelMetadata metadata, Object container)\r\n at System.Web.Http.Validation.DefaultBodyModelValidator.ShallowValidate(ModelMetadata metadata, ValidationContext validationContext, Object container)\r\n at System.Web.Http.Validation.DefaultBodyModelValidator.ValidateNodeAndChildren(ModelMetadata metadata, ValidationContext validationContext, Object container)\r\n at System.Web.Http.Validation.DefaultBodyModelValidator.ValidateProperties(ModelMetadata metadata, ValidationContext validationContext)\r\n at System.Web.Http.Validation.DefaultBodyModelValidator.ValidateNodeAndChildren(ModelMetadata metadata, ValidationContext validationContext, Object container)\r\n at System.Web.Http.Validation.DefaultBodyModelValidator.Validate(Object model, Type type, ModelMetadataProvider metadataProvider, HttpActionContext actionContext, String keyPrefix)\r\n at System.Web.Http.ModelBinding.FormatterParameterBinding.<>c_DisplayClass1.b_0(Object model)\r\n at System.Threading.Tasks.TaskHelpersExtensions.<>c__DisplayClass361.<>c__DisplayClass38.<Then>b__35()\r\n at System.Threading.Tasks.TaskHelpersExtensions.<>c__DisplayClass49.<ToAsyncVoidTask>b__48()\r\n at System.Threading.Tasks.TaskHelpers.RunSynchronously[TResult](Func1 func, CancellationToken cancellationToken)"}
I wasnt having this problem with the rc bits but then I have only started to use the restsharp libary with the rtm bits.
Any help would be great.
In addition to adding [DataMember(IsRequired = true)] to the property, you'll also need to ensure that the attribute [DataContract] is applied at the class level.
The data entry DataContract is being consumed by the UI to create the data entry form and the back-end whenever the form is posted. So, is it safe to say that [DataMember(IsRequired = true)] is needed for the back-end and [Required(ErrorMessage = #"Product type is required)] is needed for form validation so you can access the error message?
I'm not sure why we have to do both. Why can't we have a single attribute to be used by front-end and server side?
Related
I just created a new ASP.NET MVC application using .NET 6.0 and C# 10, and in this project template the Nullable Reference Types feature is enabled by default. But OK, I'm learning how to deal with this feature.
I had the following ViewModel class:
public class CustomerViewModel
{
public string Name { get; set; }
}
To avoid the Nullable Reference Type warning for the Name field, I created a constructor to initialize this field:
public class CustomerViewModel
{
public CustomerViewModel(string name) => Name = name;
public string Name { get; set; }
}
But now, when I try to receive this ViewModel in my controller action, the binding mechanism asks for a parameterless constructor:
public IActionResult CreateCustomer(CustomerViewModel customer)
{
}
If I add a parameterless constructor to my ViewModel, I get the Nullable Reference Type warnings again, because the Name field will not have a initial value outside the constructor.
This field is non-nullable, so I can't make it nullable by adding a question mark operator. And for me it doesn't make sense to initialize this field with a "random" value, like String.Empty.
How are you dealing with this feature? Have you ever faced a scenario like this? And how did you solve it?
Thank you.
Due to the nature of model binding (first instantiate an object, then fill its properties), there is a conflict with the Nullable Reference Types feature. However, there is a good blog post which offers 3 ways of dealing with this:
Declare all fields as nullable and add a [Required] attribute
[Required]
public string? Name { get; set; }
Add the Null-forgiving operator to all non-nullable properties
public string Name { get; set; } = null!;
Disable nullability warnings for the ViewModel
#nullable disable warnings
public class CustomerViewModel
{
public string Name { get; set; }
}
Just like the author of the blog, I prefer the third approach. Since the issue only occurs on classes that require a parameterless constructor, the nullable check can be disabled for these classes only. All properties remain uncluttered.
I have this action in Web Api controller:
public Data GetData(ComplexModel model)
and model is
class ComplexModel
{
Guid Guid1 { get; set;}
Guid Guid2 { get; set;}
string String1 { get; set;}
}
i would like to specify custom binder for Guid type such as empty string or null would bind to empty guid and would like not use nullable type. Was trying to register model binder like this:
var pb = configuration.ParameterBindingRules;
pb.Insert(0, typeof(Guid), param => param.BindWithModelBinding(new GuidBinder()));
but it is not called and I am getting invalid model state with error message that empty string cant be converted to type Guid.
Remember, ParameterBindingRules checks the controller action parameter itself (ComplexModel in your case), not the contents of the parameter. You'd need to register a parameter binding against ComplexModel and do any processing with the custom binder to validate the model instance. Seems like you're better off making the Guid properties nullable despite your reluctance to do so.
Using MVC3 and EF4.1 how do I validate on client and server more than one field in my view model?
I have a start date text box (that can be modified) and I have the original start date in a hidden field. When the user submits the form I want to check that the modied start date is no more than one month either side of the original start date.
I can't figure out how this can be done with DataAnnotation and CustomValidation (or maybe I'm going down the wrong road)? This is an example of whay I've been working with:
[MetadataType(typeof(Metadata.MyUserMetaData))]
public partial class MyUser
{
public System.DateTime DateOfBirth { get; set; }
}
Partial Class
public class MyUserMetaData
{
[CustomValidation(typeof(AmendedStartDate), "amendedstartdate", ErrorMessage = "Invalid date."]
public DateTime StartDate { get; set; };
public DateTime OriginalStartDate { get; set; };
}
Custom Validator
public class AmendedStartDate : ValidationAttribute, IClientValidatable
{
protected override ValidationResult IsValid(object value, ValidationContext validationContext)
{
// How do I get multiple field values from object value?
}
public IEnumerable<ModelClientValidationRule> GetClientValidationRules(Modelmetadata metadate, ControllerContext context)
{
var rule = new ModelClientValidationRule
{
ErrorMessage = FormatErrorMessage(metadata.GetDisplayName()),
ValidationType = "amendedstartdate"
};
yield return rule;
}
}
I know I've still to add jQuery to the view for this validator.
Instead of using data annotations implement IValidatableObject on your model class - it is simpler and much more clear in scenarios with cross validation.
If you still want to use ValidationAttribute you have two parameters in the IsValid method:
value represents validated value of the property where the attribute is assigned
context is context in which the property is validated. It also contains ObjectInstance and ObjectType properties to access the whole model and its type so you can cast the instance and access other properties.
The question asked in MVC custom validation: compare two dates has an example of a validator which compares to a second value in the model. That should get you started.
Is there an attribute I can decorate a single property on my model to tell the engine not to include the property in the validation routine?
[DoNotValidate] or [ValidateIgnore]
----------------------More info.
Ok, I need to give you more information. In my situation, I have a temporary decimal value on my model that is not persisted, that gets formatted into currency. $540,000.
In this one case I do not want to strip the formatting out before I call TryUpdateModel. When you use TryupdateModel, it mvc will try and convert that string text box value back into a decimal and Model.IsValid will return false. I know how to get around this situation, using javascript, but it would be easier if I could tell mvc not to validate that field.
Any model properties not decorated with validation attributes should be ignored.
public class MyModel
{
[Required]
public string SomeProperty { get; set; }
public string IgnoredProperty { get; set; }
}
Should validate that SomeProperty is required, but nothing will happen with IgnoredProperty.
The best tutorial IMHO on Model validation is http://weblogs.asp.net/scottgu/archive/2010/01/15/asp-net-mvc-2-model-validation.aspx
(even though it says for MVC 2, it's applicable).
Change the type of your decimal to nullable decimal to prevent required validation:
public class MyModel
{
public decimal MyValidatingDecimal { get; set; }
public decimal? MyNonValidatingDecimal { get; set; }
}
MyValidatingDecimal will be required (since it is a value-type), while MyNonValidatingDecimal will not be required.
Properties will only be validated if you explicitly apply validation attributes to them.
Since now I've used the excellent FluentValidation
library to validate my model classes. In web applications I use it in conjunction with the jquery.validate plugin to perform client side validation as well.
One drawback is that much of the validation logic is repeated on the client side and is no longer centralized at a single place.
For this reason I'm looking for an alternative. There are many examples out there showing the usage of data annotations to perform model validation. It looks very promising.
One thing I couldn't find out is how to validate a property that depends on another property value.
Let's take for example the following model:
public class Event
{
[Required]
public DateTime? StartDate { get; set; }
[Required]
public DateTime? EndDate { get; set; }
}
I would like to ensure that EndDate is greater than StartDate. I could write a custom
validation attribute extending ValidationAttribute in order to perform custom validation logic. Unfortunately I couldn't find a way to obtain the
model instance:
public class CustomValidationAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
// value represents the property value on which this attribute is applied
// but how to obtain the object instance to which this property belongs?
return true;
}
}
I found that the CustomValidationAttribute seems to do the job because it has this ValidationContext property that contains the object instance being validated. Unfortunately this attribute has been added only in .NET 4.0. So my question is: can I achieve the same functionality in .NET 3.5 SP1?
UPDATE:
It seems that FluentValidation already supports clientside validation and metadata in ASP.NET MVC 2.
Still it would be good to know though if data annotations could be used to validate dependent properties.
MVC2 comes with a sample "PropertiesMustMatchAttribute" that shows how to get DataAnnotations to work for you and it should work in both .NET 3.5 and .NET 4.0. That sample code looks like this:
[AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
public sealed class PropertiesMustMatchAttribute : ValidationAttribute
{
private const string _defaultErrorMessage = "'{0}' and '{1}' do not match.";
private readonly object _typeId = new object();
public PropertiesMustMatchAttribute(string originalProperty, string confirmProperty)
: base(_defaultErrorMessage)
{
OriginalProperty = originalProperty;
ConfirmProperty = confirmProperty;
}
public string ConfirmProperty
{
get;
private set;
}
public string OriginalProperty
{
get;
private set;
}
public override object TypeId
{
get
{
return _typeId;
}
}
public override string FormatErrorMessage(string name)
{
return String.Format(CultureInfo.CurrentUICulture, ErrorMessageString,
OriginalProperty, ConfirmProperty);
}
public override bool IsValid(object value)
{
PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(value);
object originalValue = properties.Find(OriginalProperty, true /* ignoreCase */).GetValue(value);
object confirmValue = properties.Find(ConfirmProperty, true /* ignoreCase */).GetValue(value);
return Object.Equals(originalValue, confirmValue);
}
}
When you use that attribute, rather than put it on a property of your model class, you put it on the class itself:
[PropertiesMustMatch("NewPassword", "ConfirmPassword", ErrorMessage = "The new password and confirmation password do not match.")]
public class ChangePasswordModel
{
public string NewPassword { get; set; }
public string ConfirmPassword { get; set; }
}
When "IsValid" gets called on your custom attribute, the whole model instance is passed to it so you can get the dependent property values that way. You could easily follow this pattern to create a date comparison attribute, or even a more general comparison attribute.
Brad Wilson has a good example on his blog showing how to add the client-side portion of the validation as well, though I'm not sure if that example will work in both .NET 3.5 and .NET 4.0.
I had this very problem and recently open sourced my solution:
http://foolproof.codeplex.com/
Foolproof's solution to the example above would be:
public class Event
{
[Required]
public DateTime? StartDate { get; set; }
[Required]
[GreaterThan("StartDate")]
public DateTime? EndDate { get; set; }
}
Instead of the PropertiesMustMatch the CompareAttribute that can be used in MVC3. According to this link http://devtrends.co.uk/blog/the-complete-guide-to-validation-in-asp.net-mvc-3-part-1:
public class RegisterModel
{
// skipped
[Required]
[ValidatePasswordLength]
[DataType(DataType.Password)]
[Display(Name = "Password")]
public string Password { get; set; }
[DataType(DataType.Password)]
[Display(Name = "Confirm password")]
[Compare("Password", ErrorMessage = "The password and confirmation do not match.")]
public string ConfirmPassword { get; set; }
}
CompareAttribute is a new, very useful validator that is not actually
part of
System.ComponentModel.DataAnnotations,
but has been added to the
System.Web.Mvc DLL by the team. Whilst
not particularly well named (the only
comparison it makes is to check for
equality, so perhaps EqualTo would be
more obvious), it is easy to see from
the usage that this validator checks
that the value of one property equals
the value of another property. You can
see from the code, that the attribute
takes in a string property which is
the name of the other property that
you are comparing. The classic usage
of this type of validator is what we
are using it for here: password
confirmation.
It took a little while since your question was asked, but if you still like metadata (at least sometimes), below there is yet another alternative solution, which allows you provide various logical expressions to the attributes:
[Required]
public DateTime? StartDate { get; set; }
[Required]
[AssertThat("StartDate != null && EndDate > StartDate")]
public DateTime? EndDate { get; set; }
It works for server as well as for client side. More details can be found here.
Because the methods of the DataAnnotations of .NET 3.5 don't allow you to supply the actual object validated or a validation context, you will have to do a bit of trickery to accomplish this. I must admit I'm not familiar with ASP.NET MVC, so I can't say how to do this exactly in conjunction with MCV, but you can try using a thread-static value to pass the argument itself. Here is an example with something that might work.
First create some sort of 'object scope' that allows you to pass objects around without having to pass them through the call stack:
public sealed class ContextScope : IDisposable
{
[ThreadStatic]
private static object currentContext;
public ContextScope(object context)
{
currentContext = context;
}
public static object CurrentContext
{
get { return context; }
}
public void Dispose()
{
currentContext = null;
}
}
Next, create your validator to use the ContextScope:
public class CustomValidationAttribute : ValidationAttribute
{
public override bool IsValid(object value)
{
Event e = (Event)ObjectContext.CurrentContext;
// validate event here.
}
}
And last but not least, ensure that the object is past around through the ContextScope:
Event eventToValidate = [....];
using (var scope new ContextScope(eventToValidate))
{
DataAnnotations.Validator.Validate(eventToValidate);
}
Is this useful?