![]() ![]() Select Create from the view content dropdown list (see Figure 2). Create a strongly-typed view with the Product class as the model class. Listing 2: Controllers\ProductController.vbįinally, you can create the view in Listing 3 by right-clicking the Create() action and selecting the menu option Add View. Public ActionResult Create(Product productToCreate) Public class ProductController : Controller This controller action redisplays the Create view when model state contains any errors. You can use the Product class in Listing 1 with the Create() controller action in Listing 2. If you want to completely customize the error message displayed by a validator then you can assign a custom error message to the validator's ErrorMessage property like this: Instead of displaying the error message "The UnitPrice field is required" you can display the error message "The Price field is required". The DisplayName attribute enables you to modify the name of the property when the property is displayed in an error message. The Product class illustrates how to use one additional attribute: the DisplayName attribute. Finally, the UnitPrice property must match a regular expression pattern that represents a currency amount. The Name property must have a string length that is less than 10 characters. The Name, Description, and UnitPrice properties are marked as required. The Product class in Listing 1 illustrates how to use these validator attributes. If your validation needs are not satisfied by any of the standard validators then you always have the option of creating a custom validator attribute by inheriting a new validator attribute from the base Validation attribute. Validation – The base class for all validator attributes.StringLength – Enables you to specify a maximum length for a string property.Required – Enables you to mark a property as required.RegularExpression – Enables you to validate whether the value of a property matches a specified regular expression pattern.Range – Enables you to validate whether the value of a property falls between a specified range of values.The namespace includes the following validator attributes: When you use the Data Annotations Model Binder, you use validator attributes to perform validation. Using the Data Annotation Validator Attributes This line of code registers the ataAnnotationsModelBinder as the default model binder for the entire ASP.NET MVC application. Add the following line of code to the Application_Start() event handler so that the Application_Start() method looks like this: protected void Application_Start() You must use the version of the assembly included with the Data Annotations Model Binder Sample download.įinally, you need to register the DataAnnotations Model Binder in the Global.asax file. NET Framework Service Pack 1 with the Data Annotations Model Binder. You cannot use the assembly included with. Select both the .dll assembly and the assembly and click the OK button. Next click the Browse tab and browse to the location where you downloaded (and unzipped) the Data Annotations Model Binder sample (see Figure 1).įigure 1: Adding a reference to the Data Annotations Model Binder ( Click to view full-size image) Select the menu option Project, Add Reference. In order to use the Data Annotations Model Binder in an ASP.NET MVC application, you first need to add a reference to the .dll assembly and the assembly. Although the Data Annotations Model Binder was created by the Microsoft ASP.NET MVC team, Microsoft does not offer official product support for the Data Annotations Model Binder described and used in this tutorial. ![]() It is important to understand that the Data Annotations Model Binder is not an official part of the Microsoft ASP.NET MVC framework. The advantage of using the Data Annotation validators is that they enable you to perform validation simply by adding one or more attributes – such as the Required or StringLength attribute – to a class property. In this tutorial, you learn how to use the Data Annotation validators to perform validation in an ASP.NET MVC application. Learn how to use the different types of validator attributes and work with them in the Microsoft Entity Framework. Take advantage of the Data Annotation Model Binder to perform validation within an ASP.NET MVC application.
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