Advance enum generation for lookup table through T4

Sometime back I had written simple T4 to generate enum for look up tables http://vikutech.blogspot.in/2014/01/enumeration-generation-for-lookup-table.html. Later on I had posted same on Nu-Get https://www.nuget.org/packages/t4.lookup.

This time I am going to extend it to support multiple enums, enum Id, configuration through class and different settings for enum description, columns.

Here is the entire code for generating code

 <#@ template debug="true" hostSpecific="true" #>  
 <#@ output extension=".cs" #>  
 <#@ Assembly Name="System.Data" #>  
 <#@ import namespace="System" #>  
 <#@ import namespace="System.Collections.Generic" #>  
 <#@ include file="EF.Utility.CS.ttinclude"#>  
 <#@ import namespace="System.Data.SqlClient" #>   
 <#  
   // TODO: Look for alternatives to remove connection string  
   var connectString = "data source=.;initial catalog=Test;integrated security=True";  
   var configList = new List<EnumConfiguration>{  
       new EnumConfiguration{  
         TableName = "LookupCountry",  
         EnumName = "Country",    // Can be empty, Get inherited based on table name  
         EnumColumn = new EnumColumnDetail {  
           Key = "Code",  
           EnumDesc = "Name",   // Not Mandatory  
           EnumSequence = "Id"   // Not Mandatory  
           },  
         },  
       new EnumConfiguration{  
         TableName = "LookupCountry",  
         EnumColumn = new EnumColumnDetail {  
           Key = "Code",  
           },  
         }  
       };  
   var code = new CodeGenerationTools(this);  
 #>  
 using System.CodeDom.Compiler;  
 namespace <#=    code.VsNamespaceSuggestion()#>  
 {    
      //------------------------------------------------------------------------------  
      // <auto-generated>  
      //   This code was generated from a template and will be overwritten as soon   
      //       as the template is executed.  
      //  
      //   Changes to this file may cause incorrect behavior and will be lost if  
      //   the code is regenerated.  
      // </auto-generated>  
      //------------------------------------------------------------------------------  
 <#  
   using (SqlConnection connection =  
       new SqlConnection(connectString))  
   {  
     connection.Open();  
     foreach(var config in configList)  
     {  
       if(!config.IsValid()) {  
         throw new ArgumentException("Please check the configuration carefully.");  
       }  
     #>  
   /// <summary>  
   /// <#=config.EnumNameDescription #>  
   /// <summary>  
   [GeneratedCode("T4.Lookup", "2.0")]  
   public enum <#=config.EnumNameDescription #>  
   {  
 <#  
       var command = new SqlCommand(config.ToString(), connection);  
       SqlDataReader reader = command.ExecuteReader();  
       // Call Read before accessing data.   
       while (reader.Read())  
       {  
         var enumId = String.IsNullOrEmpty(config.EnumColumn.EnumSequence) ? String.Empty : (" = " + reader[2]);  
 #>  
     /// <summary>  
     /// <#=          reader[1] #>  
     /// </summary>  
           <#=reader[0] #><#=enumId#>,   
 <#  
       }  
       reader.Close();   
 #>  
   }  
 <#  
     }  
   }  
 #>  
 }  
 <#+  
     /// <summary>  
   /// Enum configuration details  
   /// </summary>  
   internal class EnumConfiguration  
   {  
     /// <summary>  
     /// The enum name  
     /// </summary>  
     private string _enumName;  
     /// <summary>  
     /// The enum name description for XML comment  
     /// </summary>  
     private string _enumNameDesc;  
     public string TableName { get; set; }  
     /// <summary>  
     /// Gets or sets the name of the enum.  
     /// </summary>  
     /// <value>  
     /// The name of the enum.  
     /// </value>  
     public string EnumName  
     {  
       get  
       {  
         return String.IsNullOrEmpty(_enumName) ? TableName : _enumName;  
       }  
       set  
       {  
         _enumName = value;  
       }  
     }  
     /// <summary>  
     /// Gets or sets the enum name description.  
     /// </summary>  
     /// <value>  
     /// The enum name description.  
     /// </value>  
     public string EnumNameDescription  
     {  
       get  
       {  
         return String.IsNullOrEmpty(_enumNameDesc) ? EnumName : _enumNameDesc;  
       }  
       set  
       {  
         _enumNameDesc = value;  
       }  
     }  
     /// <summary>  
     /// Gets or sets the enum column details.  
     /// </summary>  
     /// <value>  
     /// The enum column details.  
     /// </value>  
     public EnumColumnDetail EnumColumn { get; set; }  
     /// <summary>  
     /// Determines whether this instance is valid.  
     /// </summary>  
     /// <returns></returns>  
     public bool IsValid()  
     {  
       return (!String.IsNullOrEmpty(TableName) && EnumColumn != null &&  
         !String.IsNullOrEmpty(EnumColumn.Key));  
     }  
     /// <summary>  
     /// Returns SQL query string.  
     /// </summary>  
     /// <returns>  
     /// Query string for SQL.  
     /// </returns>  
     public override string ToString()  
     {  
       if (IsValid())  
       {  
         // Generate SQL query  
         return String.Format("SELECT {0} AS EnumKey, {1} AS EnumDesc {3} FROM {2} order by {0}",  
           EnumColumn.Key, EnumColumn.EnumDesc, TableName,  
           String.IsNullOrEmpty(EnumColumn.EnumSequence) // Sequence number, if needed  
           ? String.Empty :  
           ", " + EnumColumn.EnumSequence);   
       }  
       return null;  
     }  
   }  
   /// <summary>  
   /// Generating enum column details  
   /// </summary>  
   internal class EnumColumnDetail  
   {  
     /// <summary>  
     /// The enum description  
     /// </summary>  
     private string _enumDesc;  
     /// <summary>  
     /// Gets or sets the key for enum that would be used.  
     /// </summary>  
     /// <value>  
     /// The key.  
     /// </value>  
     public string Key { get; set; }  
     /// <summary>  
     /// Gets or sets the enum description column.  
     /// </summary>  
     /// <value>  
     /// The enum description column.  
     /// </value>  
     public string EnumDesc  
     {  
       get  
       {  
         return String.IsNullOrEmpty(_enumDesc) ? Key : _enumDesc;  
       }  
       set  
       {  
         _enumDesc = value;  
       }  
     }  
     /// <summary>  
     /// Gets or sets the enum sequence Id.  
     /// </summary>  
     /// <value>  
     /// The enum sequence Id.  
     /// </value>  
     public string EnumSequence { get; set; }  
   }  
  #>  

connectString : The Sql connection string to retrieve tables from look up.

EnumConfiguration class is created to put up configuration for enum generation. configList is initialized to set multiple values based on need.

These are the details to configure enum generation:
TableName : The name of look up table. [Mandatory]
EnumName : Desired enum name associated with TableName. If not provided, get same name as                       table name. [Not-Mandatory]
EnumColumn :
       Key : The column name of table to generate enum names. [Mandatory]
       EnumDesc : The column name of table to generate XML description for each enum name.                             [Not-Mandatory]
       EnumSequence : The column name of table to generate underlying enum value.
                                 [Not-Mandatory]