LIOT/EMIS.Web/Controls/DataAnnotations/CustomerMetadataProvider.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.ComponentModel.DataAnnotations;
using System.Xml.Linq;
using Bowin.Common.XML;
using System.Reflection;

namespace EMIS.Web.Controls.DataAnnotations
{
    public class CustomerMetadataProvider : DataAnnotationsModelMetadataProvider
    {
        private class SpecialTypeConfig
        {
            public string FullName { get; set; }
            public string MetadataType { get; set; }
            public string Assembly { get; set; }
        }

        private List<SpecialTypeConfig> specialTypeList;
        private List<SpecialTypeConfig> SpecialTypeList
        {
            get
            {
                if (specialTypeList == null)
                {
                    string configPath = HttpContext.Current.Server.MapPath("~/Config/DataAnnotations.xml");

                    XElement config = XElement.Load(new System.IO.FileStream(configPath, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Read), LoadOptions.None);
                    if (config.Elements().Count() == 0)
                    {
                        specialTypeList = new List<SpecialTypeConfig>();
                    }
                    specialTypeList = (from t in config.Elements("MetadataTypes")
                                       from x in t.Elements("Metadata")
                                       select new SpecialTypeConfig
                                        {
                                            FullName = x.Attribute("Name").GetStringValue(),
                                            MetadataType = x.Attribute("MetadataType").GetStringValue(),
                                            Assembly = t.Attribute("Assembly").GetStringValue()
                                        }).ToList();
                }

                return specialTypeList;
            }
        }

        protected override System.ComponentModel.ICustomTypeDescriptor GetTypeDescriptor(Type type)
        {
            string typeKeyName = type.Namespace + "." + type.Name;
            var specialType = this.SpecialTypeList.FirstOrDefault(x => x.FullName == typeKeyName);
            if (specialType != null)
            {
                var metaDataAssambly = Assembly.Load(specialType.Assembly);
                var metaDatType = metaDataAssambly.GetType(specialType.MetadataType);
                if (metaDatType != null)
                {
                    return (new AssociatedMetadataTypeTypeDescriptionProvider(type, metaDatType))
                        .GetTypeDescriptor(type);
                }
            }

            return base.GetTypeDescriptor(type);
        }
    }
}