![]() However, run the application, and notice that the validation rules are still applied when you enter data. Open the Student.cs file or the Enrollment.cs file, and notice that the data validation attributes you applied earlier are no longer in the file. Save the ContosoModel.edmx file to apply the changes. In the Refresh tab, select Tables and Finish. Even though you have not changed the database, this process will regenerate the classes. Once again, right-click on the design surface and select Update Model from Database. To regenerate the automatically-generated classes, open the ContosoModel.edmx file. These attributes will not be lost when you regenerate the model classes because the metadata attribute is applied in partial classes that are not regenerated. By applying the metadata attribute to the partial class, you ensure that the data validation attributes will be applied to the automatically-generated class. Notice that each class is marked as a partial class, and each matches the name and namespace as the class that is automatically generated. Replace the contents of the file with the following code. In the Models folder, add a class named PartialClasses.cs. Now, you must associate the model classes with the metadata classes. The Display attribute is used to change the value used for text labels. These metadata classes contain all of the validation attributes that you had previously applied to the model classes. Replace the code in Metadata.cs with the following code. In the Models folder, add a class named Metadata.cs. In this approach, the model class can be regenerated without losing all of the attributes that have been applied to the metadata class. When you associate the model class to the metadata class, those attributes are applied to the model. To avoid this problem, you can add a metadata class that contains the attributes. This approach can be very inefficient and prone to losing important validation rules. Add metadata classesĪdding the validation attributes directly to the model class works when you do not expect the database to change however, if your database changes and you need to regenerate the model class, you will lose all of the attributes you had applied to the model class. You will receive this error: The field Grade must be between 0 and 4. Click List of enrollments and select Edit. If you attempt to enter more than 50 characters, an error message is displayed. Public Nullable EnrollmentDate Ĭlick List of students and select Edit. Add the following highlighted code to the class. Select Models > ContosoModel.edmx > ContosoModel.tt and open the Student.cs file. You will also restrict Grade to values between 0 and 4. If a user provides more than 50 characters for one of those values, the page will crash when attempting to save the value to the database. In the database, these values are limited to 50 characters however, in your web application that character limit is currently not enforced. In this tutorial, you will add data annotations to restrict the length of the values provided for the FirstName, LastName, and MiddleName properties. You can also apply formatting attributes that change how the properties are displayed such as, changing the value used for text labels. These annotations are applied throughout your web application for the specified property. To specify more data validation rules, you can add data annotations to your model class. For example, you can only provide a number for the Grade property. Just write the “FluentValidation” and download version 8.6.1 since “FluentValidation.Mvc5” is = "", new => model.As you saw in an earlier topic, some data validation rules are automatically applied to the user input. To use the fluent validators, we first need to download it from the NuGet packages. This library is available in the NuGet package so it is easy to add to the application. So, it has an advantage over data annotation validation. This will be separated from the business logic. What is Fluent Validation?įluent validation is a validation library for. Now we will see with the help of fluent validation. We all knew about the validation through data annotation. In fact, if you observe the latest Asp.Net technologies, you could find out that the validation feature was given extreme importance with fine updates.Īsp.net MVC provides a set of validations that is easy to use. If the input is not valid then throw a validation message. Validation makes sure that user input is valid or not. ![]() Fluent Validation in ASP.NET MVC Introduction ![]()
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