In a standard application I have the following:
[Required]
[DisplayName("Email Address")]
public string EmailAddress { get; set; }
...this in turn generates a label for this form field automatically in English.
Now, if I need my app to support 5 languages, what is the best approach from a ASP.NET MVC application to handle this?
Scope of application is about 400 - 600 data fields.
UPDATE: I will also require support for updating small sections of text in the application like page names and introductions to each form (small paragraph).
Instead of assigning the actual values to the attribute properties, assign keys for resource strings. Then, you can use a custom ModelMetadataProvider that is aware of the localization context and will provide the appropriate string. To get a better solution, you can make your custom ModelMetadataProvider infer conventions, (which cuts down on the need for verbose attributes).
Phil Haack has a blog article called Model Metadata and Validation Localization using Conventions that explains how this works. There is also a corresponding NuGet package called ModelMetadataExtensions with source code available on github at https://github.com/Haacked/mvc-metadata-conventions .
As a side note, I'd recommend reviewing some of the awesome answers I got on an old question of mine: Effective Strategies for Localization in .NET. They don't specifically address your question, but will be very helpful if you are working on a multilingual .NET app.