T4 Generates my business objects for me

I have finally started understanding/applying Oleg Synch's T4 code generation tutorials. I'm at least to the point where I've made something useful. My goal was to design a business object generator that would be reusable between persistence and ui changes (actual code changes, or swapping out to a completely different layer) without recompiling, or making any changes what-so-ever in the business module. It consists of a Template that defines what a business object class should look like, and related scripts for particular business object details.

The main difficulties were:

• validation 
• centralized validation model
• being capable of providing multiple field specific error messages, instead of just the first one that is discovered
  
• mapping objects
• looking for a way to cope with Linq-To-Sql's entities, while maintaining persistance indepdendence

What remains:

• Validation
• Investigate ways to push validation logic out to the client-side
• Decide on an extensibility option
• Partial classes
• Would this allow someone to implement additional functionality in another assembly? That would be against the design.
  
• Inheritance
• Everyone nowadays is avoiding inheritance in favor of interfaces
  
• Direct Script (not the generic template, the script specific to a business object type) modification 
• Make the class generic so it can hold another object for additional functionality

The template and script are included.

The template BusinessObjectTemplate.tt:

<#@ assembly name="System.Core" #>
<#@ import namespace="System.Collections.Generic" #>
<#@ Import Namespace="System.Linq" #>
<#+

    public class BusinessPropertyT4
    {
        private readonly string _typeString;
        public string TypeString { get { return _typeString; } }
      
        public BusinessPropertyT4(string type )
        {
            _typeString = type;
        }
        public string BoolValidation { get; set; }
        public string RuleViolationMessage { get; set; }
        public bool CopyExclude {get; set;}
    }
public class BusinessObjectTemplate : Template
{
    public string BusinessName;
  
    public IDictionary PropertyList;  
    public override string TransformText()
    {
#>using System;
using System.Collections.Generic;
using BReusable;
namespace DefectSeverityAssessmentBusiness.<#=BusinessName #>
{
    public class Model<#=BusinessName #>:I<#=BusinessName #>
    {
  
        #region I<#=BusinessName #> Members
        <#+
        PushIndent("\t");
        PushIndent("\t");
        foreach (string item in PropertyList.Keys)
        {
            WriteLine("public "+PropertyList[item].TypeString +" "+ item+" { get; set; }");
        }
        PopIndent();
        PopIndent();
     #>  
        #endregion
  
        public IEnumerable GetRuleViolations()
        {
        <#+
        PushIndent("\t");
        PushIndent("\t");
        foreach (string item in PropertyList.Keys)
        {
            if(string.IsNullOrEmpty(PropertyList[item].BoolValidation)==false
                && string.IsNullOrEmpty(PropertyList[item].RuleViolationMessage)==false)
                {
            WriteLine("\tif ("+PropertyList[item].BoolValidation+")");
            WriteLine("\t\t yield return new RuleViolation(\""+PropertyList[item].RuleViolationMessage
                +"\",Member.Name(x=>x."+item+"));");
                }
        }
        PopIndent();
        PopIndent();
     #>

            //if (Latitude == 0 || Longitude == 0)
            //    yield return new RuleViolation("Make sure to enter a valid address!", "Address");

            yield break;
        }
        ///

        /// This is validated in a unit test to ensure accuracy and that it is not out of sync with
        /// the number of members the interface has
        ///
        /// name="T">
        ///
name="dest">
        ///
name="source">
        ///
name="includeIdentifier">
        ///
        public static Dictionary Action> GenerateActionDictionary(T dest, I<#=BusinessName #> source, bool includeIdentifier)
    where T : I<#=BusinessName #>
        {
            var result = new Dictionary Action>
                {
<#+
        PushIndent("\t");
        PushIndent("\t");
        PushIndent("\t");
        PushIndent("\t");
        foreach (string item in PropertyList.Keys)
        {
            if(PropertyList[item].CopyExclude==false)
            {
            WriteLine("\t{Member.Name(x=>x."+item+"),");
            WriteLine("\t\t()=>dest."+item+"=source."+item+"},");
            }
        }
        PopIndent();
        PopIndent();
        PopIndent();
        PopIndent();
     #>
  
                };

            return result;

        }

        ///

        /// Designed for copying the model to the db persistence object or ui display object
        ///
        /// name="T">
        ///
name="creator">
        ///
name="source">
        ///
name="includeIdentifier">
        ///
name="excludeList">
        ///
        public static T CopyData(Func creator, I<#=BusinessName #> source, bool includeIdentifier,
            ICollection excludeList) where T : I<#=BusinessName #>
        {
            return CopyDictionary I<#=BusinessName #>>.CopyData(
                GenerateActionDictionary, creator, source, includeIdentifier, excludeList);
        }
        ///

        /// Designed for copying the ui to the model
        ///
        /// name="T">
        ///
name="validation">
        ///
name="creator">
        ///
name="source">
        ///
name="includeIdentifier">
        ///
name="excludeList">
        ///
        public static T CopyData(IValidationDictionary validation, Func creator,
            I<#=BusinessName #> source, bool includeIdentifier, ICollection excludeList)
             where T : I<#=BusinessName #>
        {
            return CopyDictionary I<#=BusinessName #>>.CopyData(
                GenerateActionDictionary, validation, creator, source, includeIdentifier, excludeList);
        }

    } // end class
    public interface I<#=BusinessName #>
    {  
<#+
        PushIndent("\t");
        PushIndent("\t");
        foreach (string item in PropertyList.Keys)
        {
            WriteLine(PropertyList[item].TypeString+" "+item+" { get; set; }");
        }
        PopIndent();
        PopIndent();
     #>
    }
}//end namespace
        <#+
        PopIndent();
        return this.GenerationEnvironment.ToString();
    }
}
#>

The first script ModelRegistrationTemplate.tt

<#@ template language="C#v3.5" hostspecific="True" debug="True" #>
<#@ output extension="cs" #>
<#@ include file="T4Toolbox.tt" #>
<#@ include file="../BusinessObjectTemplate.tt" #>
<#
    BusinessObjectTemplate template = new BusinessObjectTemplate();
    template.BusinessName="Registration";
  
    template.PropertyList=new Dictionary{
        {"UserName",new BusinessPropertyT4("string"){BoolValidation="String.IsNullOrEmpty(UserName)",
            RuleViolationMessage="UserName is required"/*,CopyExclude=true */}},
        {"Name",new BusinessPropertyT4("string")},
        {"Email",new BusinessPropertyT4("string")},
        {"MailCode",new BusinessPropertyT4("string")},
        {"TelephoneNumber",new BusinessPropertyT4("string")},
        {"OrganizationId",new BusinessPropertyT4("int?")},
        {"OrganizationSponsorId",new BusinessPropertyT4("int?")},
    };
    template.Render();
#>

And the final output:

using System;
using System.Collections.Generic;
using BReusable;
namespace DefectSeverityAssessmentBusiness.Registration
{
    public class ModelRegistration:IRegistration
    {
  
        #region IRegistration Members
        public string UserName { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
        public string MailCode { get; set; }
        public string TelephoneNumber { get; set; }
        public int? OrganizationId { get; set; }
        public int? OrganizationSponsorId { get; set; }
  
        #endregion
  
        public IEnumerable<RuleViolation> GetRuleViolations()
        {
            if (String.IsNullOrEmpty(UserName))
                 yield return new RuleViolation("UserName is required",Member.Name<ModelRegistration>(x=>x.UserName));

            //if (Latitude == 0 || Longitude == 0)
            //    yield return new RuleViolation("Make sure to enter a valid address!", "Address");

            yield break;
        }
        ///

        /// This is validated in a unit test to ensure accuracy and that it is not out of sync with
        /// the number of members the interface has
        ///
        ///
        ///

        ///

        ///

        ///
        public static Dictionary<string, Action> GenerateActionDictionary(T dest, IRegistration source, bool includeIdentifier)
    where T : IRegistration
        {
            var result = new Dictionary<string, Action>
                {
                    {Member.Name<IRegistration>(x=>x.UserName),
                        ()=>dest.UserName=source.UserName},
                    {Member.Name<IRegistration>(x=>x.Name),
                        ()=>dest.Name=source.Name},
                    {Member.Name<IRegistration>(x=>x.Email),
                        ()=>dest.Email=source.Email},
                    {Member.Name<IRegistration>(x=>x.MailCode),
                        ()=>dest.MailCode=source.MailCode},
                    {Member.Name<IRegistration>(x=>x.TelephoneNumber),
                        ()=>dest.TelephoneNumber=source.TelephoneNumber},
                    {Member.Name<IRegistration>(x=>x.OrganizationId),
                        ()=>dest.OrganizationId=source.OrganizationId},
                    {Member.Name<IRegistration>(x=>x.OrganizationSponsorId),
                        ()=>dest.OrganizationSponsorId=source.OrganizationSponsorId},
  
                };

            return result;

        }

        ///

        /// Designed for copying the model to the db persistence object or ui display object
        ///
        ///
        ///

        ///

        ///

        ///

        ///
        public static T CopyData(Func creator, IRegistration source, bool includeIdentifier,
            ICollection<string> excludeList) where T : IRegistration
        {
            return CopyDictionaryIRegistration>.CopyData(
                GenerateActionDictionary, creator, source, includeIdentifier, excludeList);
        }
        ///

        /// Designed for copying the ui to the model
        ///
        ///
        ///

        ///

        ///

        ///

        ///

        ///
        public static T CopyData(IValidationDictionary validation, Func creator,
            IRegistration source, bool includeIdentifier, ICollection<string> excludeList)
             where T : IRegistration
        {
            return CopyDictionaryIRegistration>.CopyData(
                GenerateActionDictionary, validation, creator, source, includeIdentifier, excludeList);
        }

    } // end class
    public interface IRegistration
    {  
        string UserName { get; set; }
        string Name { get; set; }
        string Email { get; set; }
        string MailCode { get; set; }
        string TelephoneNumber { get; set; }
        int? OrganizationId { get; set; }
        int? OrganizationSponsorId { get; set; }
    }
}//end namespace
        

The CopyDictionary class is as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;

namespace DefectSeverityAssessmentBusiness
{
    internal static class CopyDictionary where T:TU
    {
        ///

        ///
        ///
        ///

        ///

        ///

        ///

        ///
null for no exclusions
        ///
        public static T CopyData(Funcbool, Dictionary<string, Action>> actionDictionaryFunc,
            Func creator, TU source, bool includeIdentifier,ICollection<string>excludeList)  
        {
            return CopyDataMaster(actionDictionaryFunc, creator, source, includeIdentifier,excludeList, kvp => kvp.Value());
        }

        ///

        /// Attempts to copy data, stops on first error, adds to validation dictionary, throws the exception
        ///
        ///

        ///

        ///

        ///

        ///

        ///
null for no exclusions
        ///
        public static T CopyData(Funcbool, Dictionary<string, Action>> actionDictionaryFunc,
            IValidationDictionary validation, Func creator,
            TU source, bool includeIdentifier,ICollection<string> excludeList)
        {
            var result= CopyDataMaster(actionDictionaryFunc, creator, source, includeIdentifier,excludeList,
                kvp =>
                    {
                        try
                        {
                            kvp.Value();
                        }
                        catch (Exception exception)
                        {
                            validation.AddError(kvp.Key,exception.Message);
                            //TODO: log error?
                        }
                    });
            if(validation.IsValid==false)
                throw new ValidationException("Validation contains errors");
            return result;
        }

        private static T CopyDataMaster(Funcbool, Dictionary<string, Action>> actionDictionaryFunc,
            Func creator,TU source, bool includeIdentifier,ICollection<string> excludeList,
            Action<KeyValuePair<string, Action>> action)
        {
            var result = creator();
            foreach (var kvp in actionDictionaryFunc(result,source,includeIdentifier))
            {
                if(excludeList==null || excludeList.Contains(kvp.Key)==false)
                action(kvp);
            }
          
            return result;
        }

    }
}