Hi!

I'm glad you wrote this in the EPiServer 7.5 forum since it's a piece of cake with the new support for the IMetadataAware attribute. Here is a generic attribute:

using System;
using System.Web.Mvc;

namespace EPiServer.Samples
{
    public class PropertyEditRestrictionAttribute : Attribute, IMetadataAware
    {
        public PropertyEditRestrictionAttribute(string[] allowedRoles)
        {
            AllowedRoles = allowedRoles;
        }

        public string[] AllowedRoles { get; set; }

        public void OnMetadataCreated(ModelMetadata metadata)
        {
            foreach(string role in AllowedRoles)
            {
                if (EPiServer.Security.PrincipalInfo.CurrentPrincipal.IsInRole(role))
                {
                    return;
                }
            }
            metadata.IsReadOnly = true;
        }
    }
}

And the usage would be something like:

        [PropertyEditRestriction(new string[] {"Administrators"})]
        public virtual ContentReference TeaserBlock { get; set; }

Thank you Linus!

@Linus. I implemented the above code. I can edit TeaserBlock property in some role other than administrator eventhough it is restricted in the above code. Why is it so? 

@Gayathri: Are you using EPiServer 7.5? If so, the block should not be editable unless you are in one of the roles configured. I have written an even more complete attribute that both sets the editor to read only as well as securing the data when changed so noone can bypass the UI:

using System;
using System.ComponentModel.DataAnnotations;
using System.Web.Mvc;
using EPiServer.Core;

namespace samples
{
    public class PropertyEditRestrictionAttribute : ValidationAttribute, IMetadataAware
    {
        public PropertyEditRestrictionAttribute(string[] allowedRoles)
        {
            AllowedRoles = allowedRoles;
        }

        public string[] AllowedRoles { get; set; }

        public void OnMetadataCreated(ModelMetadata metadata)
        {
            foreach(string role in AllowedRoles)
            {
                if (EPiServer.Security.PrincipalInfo.CurrentPrincipal.IsInRole(role))
                {
                    return;
                }
            }
            metadata.IsReadOnly = true;
        }

        public override string FormatErrorMessage(string name)
        {
 	         return "You do not have access to change " + name;
        }

        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            var contentData = validationContext.ObjectInstance as IContentData;
            if(contentData == null)
            {
                //This attribute only handles instances of IContentData.
                return ValidationResult.Success;
            }
            if(!contentData.Property[validationContext.MemberName].IsModified)
            {
                return ValidationResult.Success;
            }
            return base.IsValid(value, validationContext);
        }

        public override bool RequiresValidationContext
        {
            get
            {
                return true;
            }
        }

        public override bool IsValid(object value)
        {
            foreach (string role in AllowedRoles)
            {
                if (EPiServer.Security.PrincipalInfo.CurrentPrincipal.IsInRole(role))
                {
                    return true;
                }
            }
            return false;
        }
    }
}

@Linus: Perfect.. that works great and Thanks. And one more question regarding this http://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=76138