Introduction to Structure Map

using StructureMap;
using StructureMap.Configuration.DSL;
using StructureMap.Configuration;
using StructureMap.Pipeline;
public class ServiceRegistry : Registry
{
    protected override void configure()
    {
        ForRequestedType<IUserService>()
            .TheDefaultIsConcreteType<UserService>();
        ForRequestedType<ISearchRepository>()
            .TheDefaultIsConcreteType<SearchRepository>();
    }
}
public class DBServiceRegistry : Registry
{
    protected override void configure()
    {
        ForRequestedType<DBDataContext>()
            .TheDefaultIs(() => new DBDataContext())
            .CacheBy(InstanceScope.Hybrid);
    }
}

The above configuration of Structure Map will inject UserService when there is a request to IUserService.

Similarly, it will inject SearchRepository when it finds a request to ISearchRepository.

Types of instance scoping

Types of Instance Scoping Provided by Structure Map

1. Perrequest: The default operation. A new instance will be created for each request.
2. Singleton: A single instance will be shared across all requests
3. Thread local: A single instance will be created for each requesting thread. Caches the instances with ThreadLocalStorage.
4. Http context: A single instance will be created for each HttpContext. Caches the instances in the HttpContext.Items collection.
5. Hybrid: Uses HttpContext storage if it exists, otherwise uses ThreadLocal storage

Step 3. Register with the Structure Map Registry

using StructureMap;
public static class Bootstrapper
{
    public static void ConfigureStructureMap()
    {
        StructureMapConfiguration.AddRegistry(new DBServiceRegistry());
        StructureMapConfiguration.AddRegistry(new ServiceRegistry());
    }
}

Note. You could use Step 2 and Step 3 classes in a Single File Named Bootstrapper.cs. This file could be located at the Folder which has Global.asax.

Step 4. Controller Factory For Structure Map

using StructureMap;
using System;
using System.Web.Mvc;
using System.Web.Routing;

public class StructureMapControllerFactory : DefaultControllerFactory
{
    protected override IController GetControllerInstance(Type controllerType)
    {
        try
        {
            return ObjectFactory.GetInstance(controllerType) as Controller;
        }
        catch (StructureMapException)
        {
            System.Diagnostics.Debug.WriteLine(ObjectFactory.WhatDoIHave());
            throw;
        }
    }
}

The controller factory is responsible for creating controller instances. We extend the built in default controller factory with our own factory for working StructureMap with ASP.NET MVC .

Note. This file named StructuremapControllerFactory.cs could be located in the Controller Folder.

Step 5. Modify Global.asax

protected void Application_Start()
{
    RegisterRoutes(RouteTable.Routes);
    // Configure StructureMapConfiguration
    Bootstrapper.ConfigureStructureMap();
    // Set current Controller factory as StructureMapControllerFactory
    ControllerBuilder.Current.SetControllerFactory(new myFinance.Web.Controllers.StructureMapControllerFactory());
}

The above code will set our controller factory and configure StructureMap configuration when our ASP.NET MVC application is started.

Hope this article will give a basic idea...

Happy Coding