asp.net mvc dataanoation validating url

Question

can some one tell me how can i validate a url like http://www.abc.com

Answer 1

Use a regular expression data annotation, and use a regex like:

http://www\.\w+\.(com|net|edu|org)

Depending on what you need to validate; are you requiring http: or are you requiring www.? So that could change the regular expression, if optional, to:

(http://)?(www\.)?\w+\.(com|net|edu|org)

Answer 2

If, by the title of your post, you want to use MVC DataAnnotations to validate a url string, you can write a custom validator:

public class UrlAttribute : ValidationAttribute
{
    public UrlAttribute() { }

    public override bool IsValid(object value)
    {
        //may want more here for https, etc
        Regex regex = new Regex(@"(http://)?(www\.)?\w+\.(com|net|edu|org)");

        if (value == null) return false;

        if (!regex.IsMatch(value.ToString())) return false;

        return true;
    }
}

Phil Haack has a good tutorial that goes beyond this and also includes adding code to validate on the client side via jQuery: http://haacked.com/archive/2009/11/19/aspnetmvc2-custom-validation.aspx