ASP.NET Core uses Microsoft.AspNetCore.Mvc **ModelMetadataType** instead of System.ComponentModel.DataAnnotations.**MetadataType** source Try changing your attribute to [ModelMetadataType(typeof(ComponentModelMetaData))]
Issue – Model Binder Order This is, unfortunately, the standard behavior of Validator.TryValidateObject which does not recursively validate the property values of the object As pointed out in Jeff Handley’s article on Validating Object and Properties with the Validator, by default, the validator will validate in order: Property-Level Attributes Object-Level Attributes Model-Level implementation IValidatableObject The … Read more
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}’ … Read more
In Entity Framework 6.1+ you can use this attribute on your model: [Index(IsUnique=true)] You can find it in this namespace: using System.ComponentModel.DataAnnotations.Schema; If your model field is a string, make sure it is not set to nvarchar(MAX) in SQL Server or you will see this error with Entity Framework Code First: Column ‘x’ in table … Read more
The reason for making a property nullable and marked with the [Required] attribute is to protect against under-posting attacks. It also allows you to display an initial empty value in the view rather than the default value for the property. This is typically done with value type properties in view models. An under-posting attack is … Read more
Extension method: public static T GetAttributeFrom<T>(this object instance, string propertyName) where T : Attribute { var attrType = typeof(T); var property = instance.GetType().GetProperty(propertyName); return (T)property .GetCustomAttributes(attrType, false).First(); } Code: var name = player.GetAttributeFrom<DisplayAttribute>(nameof(player.PlayerDescription)).Name; var maxLength = player.GetAttributeFrom<MaxLengthAttribute>(nameof(player.PlayerName)).Length;
The specifications for the HTML5 date picker state that the date must be in the format yyyy-MM-dd (ISO format). This means that you DisplayFormatAttribute must be [DisplayFormat(DataFormatString = “{0:yyyy-MM-dd}”, ApplyFormatInEditMode = true)] public string MyDate { get; set; } Alternatively you can manually add the format using @Html.TextBoxFor(m => m.MyDate, “{0:yyyy-MM-dd}”, new { @type = … Read more
This problem can be easily solved by using view models. View models are classes that are specifically tailored to the needs of a given view. So for example in your case you could have the following view models: public UpdateViewView { [Required] public string Id { get; set; } … some other properties } public … Read more
To create a custom data annotation validator follow these gudelines: Your class has to inherit from System.ComponentModel.DataAnnotations.ValidationAttribute class. Override bool IsValid(object value) method and implement validation logic inside it. That’s it. IMPORTANT Caution Sometimes developers check that value is not null/empty and return false. This is usually incorrect behaviour, because that’s on Required validator to … Read more
Apparently my question was already answered at How to replace the default ModelState error message in Asp.net MVC 2? . I’ll summarize it here: Create App_GlobalResources folder for your project (right click to project -> Add -> Add ASP.NET folder -> App_GlobalResources). Add a resx file in that folder. Say MyNewResource.resx. Add resource key PropertyValueInvalid … Read more