ASP.NET MVC 3 Pattern for dynamic validation attributes including client side

Question

My validation requirements for a the fields in a form are contained in an external table so that they can be updated without altering and rebuilding the code.

I have approximatley 100 fields with a mixture of validation requirements - range, required, regular expression and dependency on other fields. One example is date range validation. A date of birth field requires a date range which is between -10 years and -50 years of the current date.

I have read around the subject but have not identified a pattern for the complete solution.

I am using Visual Studio 2010 with MVC 3 and Entity Framework.

Any help with this would be gratefully received. Thanks in advance.

Answer 1

In a simple level I think you can still use the built-in Data-Annotations validation attributes to does the validation and for that you should map the validation rules stored in the table to the attributes.

I think all you have to do is create a custom model validation provider by inheriting the class ModelValidatorProvider . This class contains a single method called GetValidators that returns the collection validators for that model.

You have to implement the GetValidators method and in there you have to make a database call to get the validation rules for the model from the database (or from cache?) and convert them into ModelValidator s. You could still use the built-in DataAnnotationsModelValidator to do the validations.

I would suggest you to look into the source code of DataAnnotationsModelValidatorProvider that will give you all the information. In that class what they are doing is basically iterating all the validation attributes applied to the model properties and converting them into ModelValidator s through adapters and factories. In your case instead of attributes they are stored as records in tables and I don't think much work will be there.