Modify DataType attribute dynamically in ASP.NET MVC

Question

I have a ViewModel containing this property:

[Display(Name = "Email")]        
[DataType(DataType.EmailAddress)]        
[DisplayFormat(NullDisplayText = "Unavailable")]        
public string Email { get; set; }

Is there a way to set the DataType attribute dynamically to show it as a DataType.Text if it's showing "Unavailable" (the NullDisplayText), otherwise show it as a clickable DataType.EmailAddress?

Now, when the property value is null, it shows like Unavailable while I want to show it as Unavailable.

Answer 1

You can customize the display template of EmailAddress. To do so:

1. Create a DisplayTemplates folder under Views/Shared
2. Create an EmailAddress.cshtml file in DisplayTemplates folder

3. Add the following content to the file and save it:

   @model string
   @if (string.IsNullOrEmpty(Model))
   {
       @ViewData.TemplateInfo.FormattedModelValue
   }
   else
   {
       <a href="mailto:@Model">@ViewData.TemplateInfo.FormattedModelValue</a>
   }
   

Since now, when you use a [DataType(DataType.EmailAddress)] attribute for a property, your EmailAddress display template will be used.

You can put any logic inside it to do a custom render.

Note: If you want to limit the template to your specific views, let's say just for MyModel views, then create the EmailAddress template in Views\MyModel\DisplayTemplates.