Get display annotation value on mvc3 server side code

Question

Is there a way to get the value of an annotation in server side code? For example, I have:

public class Dummy
{
    [Display(Name = \"Foo\")]
    public stri         


        

Answer 1

Something like this?

string displayName = GetDisplayName((Dummy x) => x.foo);

// ...

public static string GetDisplayName<T, U>(Expression<Func<T, U>> exp)
{
    var me = exp.Body as MemberExpression;
    if (me == null)
        throw new ArgumentException("Must be a MemberExpression.", "exp");

    var attr = me.Member
                 .GetCustomAttributes(typeof(DisplayAttribute), false)
                 .Cast<DisplayAttribute>()
                 .SingleOrDefault();

    return (attr != null) ? attr.Name : me.Member.Name;
}

Or, if you want to be able to call the method against an instance and take advantage of type inference:

var dummy = new Dummy();
string displayName = dummy.GetDisplayName(x => x.foo);

// ...

public static string GetDisplayName<T, U>(this T src, Expression<Func<T, U>> exp)
{
    var me = exp.Body as MemberExpression;
    if (me == null)
        throw new ArgumentException("Must be a MemberExpression.", "exp");

    var attr = me.Member
                 .GetCustomAttributes(typeof(DisplayAttribute), false)
                 .Cast<DisplayAttribute>()
                 .SingleOrDefault();

    return (attr != null) ? attr.Name : me.Member.Name;
}

Answer 2

You will need to use reflection. Here is a sample console program that does what you want.

class Program
{
    static void Main(string[] args)
    {
        Dummy dummy = new Dummy();
        PropertyInfo[] properties = dummy.GetType().GetProperties();
        foreach (PropertyInfo property in properties)
        {
            IEnumerable<DisplayAttribute> displayAttributes = property.GetCustomAttributes(typeof(DisplayAttribute), false).Cast<DisplayAttribute>();
            foreach (DisplayAttribute displayAttribute in displayAttributes)
            {
                Console.WriteLine("Property {0} has display name {1}", property.Name, displayAttribute.Name);
            }
        }
        Console.ReadLine();
    }
}

public class Dummy
{
    [Display(Name = "Foo")]
    public string foo { get; set; }

    [Display(Name = "Bar")]
    public string bar { get; set; }
}

This would produce the following result:

http://www.codetunnel.com/content/images/reflectresult.jpg