Question

I might actually be going insane, but I can’t find a single example of how to use DataAnnotationsExtensions with Visual Basic in MVC 3. I’m tired of guessing.

Anyone one want to point me to an example or provide some simple code to show me how to use the tags?

Thank you!!

Answer 1

Well, it’s pretty straightforward actually.

1. You create a new ASP.NET MVC 3 application
2. You install the DataAnnotationsExtensions.MVC3 Nuget

3. You create a view model:

   Public Class MyViewModel
       <CreditCard(ErrorMessage:="Invalid credit card number")>
       Public Property Number As String
   End Class
   

4. A controller:

   Public Class HomeController
       Inherits System.Web.Mvc.Controller
   
       Function Index() As ActionResult
           Return View(New MyViewModel())
       End Function
   
       <HttpPost()>
       Function Index(ByVal model As MyViewModel) As ActionResult
           Return View(model)
       End Function
   End Class
   

5. And finally a view:

   @ModelType AppName.MyViewModel
   
   @Using Html.BeginForm()
       @Html.LabelFor(Function(x) x.Number)
       @Html.EditorFor(Function(x) x.Number)
       @Html.ValidationMessageFor(Function(x) x.Number)
       @<button type="submit">OK</button>
   End Using