Skip to main content

Manual model mapping - LINQ projection technique

There are various object mappers available like AutoMapper, TinyMapper, EmitMapper, ValueInjector and many more mappers. They all provide a flexible way to do the mappings from one object to another without much effort.

When it comes to performance nothing can beat good old manual mappings. The downside is, it get mixed up under projection from LINQ queries. By mixing projection, we hard code the mapping between model, if again it needs to be mapped to some other place, then write that again. The ideal approach should be separating the mapping to some other place, it also takes care of SRP pattern and also our code manageability increase by keeping projection/mapping separately.

The usage can be very simple. Here is expression technique to map one entity model to view model.

 public Expression<Func<SecurityUser, UserBasicInfo>> MapUserBasicInfo()  
 {  
      return (user) => new UserBasicInfo  
      {  
           FullName = user.Person.FirstName + " " + user.Person.MiddleName + " " + user.Person.LastName,  
           UserName = user.UserName,  
           UserId = user.Id  
      };  
 }  

Expression is available from System.Linq.Expressions namespace.

It is just a lambda expression which could be used at any place. The consumption could be really easy to use.
The examples based on Select and FirstOrDefault:

 model.Select(MapUserBasicInfo())  

 .Select(MapUserBasicInfo()).FirstOrDefault()  


In next version, I would target it through Attributes and T4 for automatic mapping generation.

Popular posts from this blog

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 tha…

LDAP with ASPNet Core Identity in MVC Core

Lightweight Directory Access Protocol (LDAP), the name itself explain it. An application protocol used over an IP network to access the distributed directory information service.

AspNet Identity Core is a new offering from Microsoft in replacement of AspNet Identity for managing users.

In this tutorial, we would be looking for implementing LDAP with AspNet Identity Core to allow users to be able to log in through AD or AspNet Identity Core members.

The first and foremost thing is to add references for consuming LDAP. This has to be done by adding reference from Global Assembly Cache (GAC) into project.json

"frameworks": { "net461": { "frameworkAssemblies": { "System.DirectoryServices": "4.0.0.0", "System.DirectoryServices.AccountManagement": "4.0.0.0" } } },
These System.DirectoryServices and System.DirectoryServices.AccountManagement references are used to consume LDAP functiona…

Configuring Ninject, Asp.Net Identity UserManager, DataProtectorTokenProvider with Owin

It can be bit tricky to configure both Ninject and Asp.Net Identity UserManager if some value is expected from DI to configure UserManager. We will look into configuring both and also use OwinContext to get UserManager.

As usual, all configuration need to be done on Startup.cs. It is just a convention but can be used with different name, the important thing is to decorate class with following attribute to make it Owin start-up:

[assembly: OwinStartup(typeof(MyProject.Web.Startup))]
Ninject configuration

Configuring Ninject kernel through method which would be used to register under Owin.

Startup.cs
public IKernel CreateKernel() { var kernel = new StandardKernel(); try { //kernel.Bind<IHttpModule>().To<HttpApplicationInitializationHttpModule>(); // TODO: Put any other injection which are required. return kernel; } catch { kernel.Dispose(); throw; }…