Skip to main content

Enum generation for lookup table through T4

Sometime there is need of mapping some values from database to code level, basically in look up tables.
I am going to generate enum based on database values. In this example, I am going for T4 template to generate up enum by using SqlDataReader.
We can have any SQL query to generate enum. In my case, Privilege code, name and description from table would generate up enum.


 <#@ template debug="true" hostSpecific="true" #>  
 <#@ output extension=".cs" #>  
 <#@ Assembly Name="System.Data" #>  
 <#@ include file="EF.Utility.CS.ttinclude"#>  
 <#@ import namespace="System.Data.SqlClient" #>   
 <#  
      var code = new CodeGenerationTools(this);  
      var connectString = "Set connection string";  
      var queryString = "select PrivilegeCode, PrivilegeName, PrivilegeDescription from Privilege";  
 #>  
 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>  
      //------------------------------------------------------------------------------  
      /// <summary>  
   /// Different permission rules for users  
   /// </summary>  
      public enum PermissionRule  
      {  
 <#  
 using (SqlConnection connection =  
       new SqlConnection(connectString))  
 {  
   SqlCommand command =  
     new SqlCommand(queryString, connection);  
   connection.Open();  
   SqlDataReader reader = command.ExecuteReader();  
   // Call Read before accessing data.   
   while (reader.Read())  
   {  
 #>  
     /// <summary>  
     /// <#=reader[1] #>  
     /// </summary>  
           /// <remarks><#=reader[2] #></remarks>  
           <#=reader[0] #>,  
 <#  
      }  
           reader.Close();   
 }  
 #>  
      }  
 }  


Set connectString variable as desired database connection.
Set queryString to table that you want to connect.


Using those three columns I am able to generate enum having name, comment and remark. Now, if lookup table changes then I just need to do “Run Custom Tool” on template which would generate up new enum values without copying/pasting values on code level.

Comments

Popular posts from this blog

Elegantly dealing with TimeZones in MVC Core / WebApi

In any new application handling TimeZone/DateTime is mostly least priority and generally, if someone is concerned then it would be handled by using DateTime.UtcNow on codes while creating current dates and converting incoming Date to UTC to save on servers. Basically, the process is followed by saving DateTime to UTC format in a database and keep converting data to native format based on user region or single region in the application's presentation layer. The above is tedious work and have to be followed religiously. If any developer misses out the manual conversion, then that area of code/view would not work. With newer frameworks, there are flexible ways to deal/intercept incoming or outgoing calls to simplify conversion of TimeZones. These are steps/process to achieve it. 1. Central code for storing user's state about TimeZone. Also, central code for conversion logic based on TimeZones. 2. Dependency injection for the above class to ...

Making FluentValidation compatible with Swagger including Enum or fixed List support

FluentValidation is not directly compatible with Swagger API to validate models. But they do provide an interface through which we can compose Swagger validation manually. That means we look under FluentValidation validators and compose Swagger validator properties to make it compatible. More of all mapping by reading information from FluentValidation and setting it to Swagger Model Schema. These can be done on any custom validation from FluentValidation too just that proper schema property has to be available from Swagger. Custom validation from Enum/List values on FluentValidation using FluentValidation.Validators; using System.Collections.Generic; using System.Linq; using static System.String; /// <summary> /// Validator as per list of items. /// </summary> /// <seealso cref="PropertyValidator" /> public class FixedListValidator : PropertyValidator { /// <summary> /// Gets the valid items /// <...

Handling JSON DateTime format on Asp.Net Core

This is a very simple trick to handle JSON date format on AspNet Core by global settings. This can be applicable for the older version as well. In a newer version by default, .Net depends upon Newtonsoft to process any JSON data. Newtonsoft depends upon Newtonsoft.Json.Converters.IsoDateTimeConverter class for processing date which in turns adds timezone for JSON data format. There is a global setting available for same that can be adjusted according to requirement. So, for example, we want to set default formatting to US format, we just need this code. services.AddMvc() .AddJsonOptions(options => { options.SerializerSettings.DateTimeZoneHandling = "MM/dd/yyyy HH:mm:ss"; });

Architecture solution composting Repository Pattern, Unit Of Work, Dependency Injection, Factory Pattern and others

Project architecture is like garden, we plant the things in certain order and eventually they grow in similar manner. If things are planted well then they will all look(work) great and easier to manage. If they grow as cumbersome it would difficult to maintain and with time more problems would be happening in maintenance. There is no any fixed or known approach to decide project architecture and specially with Agile Methodology. In Agile Methodology, we cannot predict how our end products will look like similarly we cannot say a certain architecture will fit well for entire development lifespan for project. So, the best thing is to modify the architecture as per our application growth. I understand that it sounds good but will be far more problematic with actual development. If it is left as it is then more problems will arise with time. Just think about moving plant vs a full grown tree. Coming to technical side, In this article, I will be explaining about the various techniques ...

Using Redis distributed cache in dotnet core with helper extension methods

Redis cache is out process cache provider for a distributed environment. It is popular in Azure Cloud solution, but it also has a standalone application to operate upon in case of small enterprises application. How to install Redis Cache on a local machine? Redis can be used as a local cache server too on our local machines. At first install, Chocolatey https://chocolatey.org/ , to make installation of Redis easy. Also, the version under Chocolatey supports more commands and compatible with Official Cache package from Microsoft. After Chocolatey installation hit choco install redis-64 . Once the installation is done, we can start the server by running redis-server . Distributed Cache package and registration dotnet core provides IDistributedCache interface which can be overrided with our own implementation. That is one of the beauties of dotnet core, having DI implementation at heart of framework. There is already nuget package available to override IDistributedCache i...

Kendo MVC Grid DataSourceRequest with AutoMapper

Kendo Grid does not work directly with AutoMapper but could be managed by simple trick using mapping through ToDataSourceResult. The solution works fine until different filters are applied. The problems occurs because passed filters refer to view model properties where as database model properties are required after AutoMapper is implemented. So, the plan is to intercept DataSourceRequest  and modify names based on database model. To do that we are going to create implementation of  CustomModelBinderAttribute to catch calls and have our own implementation of DataSourceRequestAttribute from Kendo MVC. I will be using same source code from Kendo but will replace column names for different criteria for sort, filters, group etc. Let's first look into how that will be implemented. public ActionResult GetRoles([MyDataSourceRequest(GridId.RolesUserGrid)] DataSourceRequest request) { if (request == null) { throw new Argume...

Using LINQ to Entity efficiently with First/FirstOrDefault/Last/LastOrDefault/Single/SingleOrDefault

We generally use these extension methods First/FirstOrDefault/Last/LastOrDefault/Single/SingleOrDefault with predicates like ctx=> ctx.Model.FirstOrDefault(item => item.Id == 1 ) Or ctx=> ctx.Model.Where(item => item.Id == 1 ).FirstOrDefault() What is the problem with these? FirstOrDefault or similar methods immediately loads all data at once. So, let's say we have fifty columns on table then all those columns data would be retrieved from DB and saved into memory. This link gives a fair idea of different function behavior.  https://msdn.microsoft.com/en-us/library/bb882641.aspx .  So, even if we require only one value from selected field it retrieves all values. What is the solution? The solution is pretty simple. Whenever we need selected items better to do projection before calling FirstOrDefault or similar methods. Ex: Selecting single item ctx.Model.Where(itm => itm.Id == 1) .Select(itm => itm.Name).FirstO...

Data seed for the application with EF, MongoDB or any other ORM.

Most of ORMs has moved to Code first approach where everything is derived/initialized from codes rather than DB side. In this situation, it is better to set data through codes only. We would be looking through simple technique where we would be Seeding data through Codes. I would be using UnitOfWork and Repository pattern for implementing Data Seeding technique. This can be applied to any data source MongoDB, EF, or any other ORM or DB. Things we would be doing. - Creating a base class for easy usage. - Interface for Seed function for any future enhancements. - Individual seed classes. - Configuration to call all seeds. - AspNet core configuration to Seed data through Seed configuration. Creating a base class for easy usage public abstract class BaseSeed<TModel> where TModel : class { protected readonly IMyProjectUnitOfWork MyProjectUnitOfWork; public BaseSeed(IMyProjectUnitOfWork MyProjectUnitOfWork) { ...

Visual Studio 2015 Code Analyzer and configuration with StyleCop

What is Diagnostic/Code Analyzer? To put it simply it is something similar to Resharper or Telerik JustCode. It analyzes codes while writing on code editor and suggest for improvements of codes through Squiggles, light icon and based on various severity. How it works? I had mentioned that it is similar to Resharper and Telerik JustCode but internal infrastructure is completely different. It is dependent on new compiler Roslyn . Roslyn has a clever compile technique, unlike older version which makes it faster and flexible for dynamic compilation without the need of the entire code base. The structure is basically divided into two categories Syntax Tree , and Semantic Model . The syntax tree is related to syntaxes only it does not require any reference check. It can be related to DOM elements structure in case of HTML.  Syntax Tree consists of very fine details as simple as WhiteSpace under the code. The Semantic Model is kind of references of Syntax Tree in which it ...

Storing and restoring Kendo Grid state from Database

There is no any built in way to store entire grid state into database and restore back again with all filters, groups, aggregates, page and page size. At first, I was trying to restore only filters by looking through DataSourceRequest. DataSourceRequest is kind of communication medium between client and server for the operation we do on grid. All the request comes via DataSourceRequest. In previous approach, I was trying to store IFileDescriptor interface which come with class FileDescriptor by looping through filters and serializing into string for saving into database but this IFileDescriptor can also contain CompositeFilterDescriptor which can be nested in nested object which are very tricky to handle. So, I had decompiled entire Kendo.MVC library and found out that all Kendo MVC controls are derived from “JsonObject”. It is there own implementation with ”Serialize” abstract function and “ToJson” function. In controls they are overriding “Serialize” method which depicts t...