Mvc data annotations validation example7/30/2023 ![]() Most of the time, the editor is a textbox but a Boolean property would require a checkbox. You may notice that each public property gets an “editor” in the form of ad hoc markup. Using Html.EditorFor with an annotated view model class. Figure 1 shows the actual result:įIGURE 1. This is one of the predefined editor helpers that gets an object-in the sample, an instance of the Article class-and renders it out within a fixed template. The CSS classes you see in the code snippet that are not prefixed with “gladiator” are all coming from the Twitter’s popular Bootstrap framework.Īs you can see, the core of the form is in the call to Html. Here’s a sample class annotated with a few attributes.Īs a side note, imagine that this code is an excerpt from a page taken from a personal site-codenamed Gladiator. To start using data annotations, you need to reference the assembly. Data annotations include both rendering and validation attributes. By using data annotations, you decorate your classes with metadata. Using Data Annotationsĭata annotations are attributes that instruct listeners on how to display or edit data. Where you don’t need a special form layout, data annotations can save you a lot of time. These tools include data annotations and template-based HTML helpers conventions include some predefined CSS classes that designers can overwrite to introduce a more appealing look-and-feel. When you’re writing the admin panel for the data in a site, for example, a plain CRUD-inspired set of views are quite good enough.ĪSP.NET MVC offers a few conventions and built-in tools to speed up this aspect of form development. ![]() Sometimes, there isn’t any need to spend much time on laying out elements. ![]() Although input forms often contain images and require the specific placement of fields, there are plenty of times that they don’t. The client validation still respects the IsInverted property.Input forms play a significant part in the organization of most web views. It's essentially the same code except it implements IClientModelValidator and has an additional AddValidation method. I wanted client side validation as well so I'm sharing my revised code to Robert's original code. I know this question is from a long time ago but someone asked in the comments section of Robert's answer how to use unobtrusive as part of the solution. You can use it like this public class Document Return propertyValue != null & propertyValue.ToString() != "" Return propertyValue != null & propertyValue.ToString() = Value.ToString() Private bool HasPropertyValue(object propertyValue) Return type.GetProperty(PropertyName).GetValue(instance) Var instance = validationContext.ObjectInstance ![]() Private object GetPropertyValue(ValidationContext validationContext) Return new ValidationResult(ErrorMessage) If (HasPropertyValue(propertyValue) & (value = null || value.ToString() = "")) Var propertyValue = GetPropertyValue(validationContext) Throw new Exception("RequiredIf: you have to indicate the name of the property to use in the validation") If (PropertyName = null || PropertyName.ToString() = "") Protected override ValidationResult IsValid(object value, ValidationContext validationContext) Public RequiredIfAttribute(string propertyName, object value = null, string errorMessage = "") Public class RequiredIfAttribute : ValidationAttribute I wrote a simple custom validation attribute that it's very readable. NET 5, but I tried to remove language features added in c# 9.0 for wider compatibility. This way, you get all the standard Required validation features. Return base.IsValid(value, validationContext) IsInverted & !Equals(actualOtherPropertyValue, OtherPropertyValue)) If (!IsInverted & Equals(actualOtherPropertyValue, OtherPropertyValue) || GetValue(validationContext.ObjectInstance, null) Object actualOtherPropertyValue = otherPropertyInfo ValidationContext.ObjectType, OtherProperty)) PropertyInfo otherPropertyInfo = validationContext Protected override ValidationResult IsValid( Public RequiredIfAttribute(string otherProperty, object otherPropertyValue) / Initializes a new instance of the class. / Gets or sets the other property name that will be used during validation. Public sealed class RequiredIfAttribute : ValidationAttribute / Provides conditional validation based on related property value. I've written a RequiredIfAttribute that requires a particular property value when a different property has a certain value (what you require) or when a different property has anything but a specific value.
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