I have this working and getting data. However, everytime I page it calls the GetAllWebExceptions, which gets all of the web exceptions records from the database. How should paging be implemented? I've only seen examples with EntityFrameworks. Does anyone have a good example using the data source with POCO or is that still to come?
<Grid x:Name="LayoutRoot" Background="White">
<ria:DomainDataSource x:Name="ErrorLogDataSource"
LoadMethodName="GetAllWebExceptions">
<ria:DomainDataSource.DomainContext>
<services:CMSContext />
</ria:DomainDataSource.DomainContext>
</ria:DomainDataSource>
<data:DataGrid x:Name="DataGridExceptions" ItemsSource="{Binding ElementName=ErrorLogDataSource, Path=Data}"
AutoGenerateColumns="True">
</data:DataGrid>
<dataControls:DataPager Source="{Binding Data, ElementName=ErrorLogDataSource}"
PageSize="20" />
in the service:
[Query(PreserveName = true)]
public IEnumerable GetAllWebExceptions()
{
return WebException.SelectAll("DATECREATED DESC");
}
You should certainly be able to use a POCO class. However your query method needs to reference it by returning a generic IEnumerable, so the rest of the system knows at compile time of your type.
The requirement is your POCO class must have some notion of identity, made up of one or more members that are marked with the [Key] metadata attribute.
For example:
public class WebException {
[Key]
string id;
// Or it could be a DateTime if you use time of occurrence as the key,
// or anything else that is unique.
// ...
// Other members
}
public class ErrorManager : DomainService {
public IEnumerable<WebException> GetAllWebExceptions() {
return WebException.SelectAll("DATECREATED DESC");
}
}
Hope that helps...
Take a look at Brad Abrams excellent walk-through on using POCO with RIA Services
Related
In ASP.NET 5, I have an IRepository interface that I used to access some databases, like this:
public interface IRepository {
IQueryable<T> QueryItems(string sql);
}
public class Repository : IRepository {
private readonly string ConnectionString;
public Repository(string connStr) {
// Save the injected connection string
this.ConnectionString = connStr;
}
public IQueryable<T> QueryItems(string sql) {
// Implementation ignored here
}
}
In my Startup.cs class, I am registering the IoC/DI like this:
services.AddTransient<IRepository>(s => new Repository("DUMMY_CONNSTR"));
That all works fine if I only have one connection string. However, how can I register and subsequently inject the correct IRepository if I use the Repository to connect to 2+ different databases with different connection strings?
services.AddTransient<IRepository>(s => new Repository("DUMMY_CONNSTR"));
services.AddTransient<IRepository>(s => new Repository("DIFFERENT_CONNSTR"));
In older IoC/DI systems, I would have use "named" implementations that could be resolved with something like a [Dependency("DUMMY")] attribute on the constructor parameter.
Any help would be appreciated.
There are a few approach that you can take one is to inject a factory and base on the specific criteria you can produce a repository, the other approach is use a Dispatcher that also produce the repository base on the criteria, below is a question that I ask with the same problem. The question below have both approach but they were codding a beta version of .net core
See this question for reference and code
You can substitute StructureMap or Autofac for the default DI container (see my blog post for detailed instructions). Both support "named" interface registration (StructureMap named instances and Autofac named and keyed services).
Additionally, if you target dnx451, you can use Autofac's WithKey attribute. Using the Visual Studio sample project from the blog post, add the following dependency in project.json:
"frameworks": {
"dnx451": {
"dependencies": {
"Autofac.Extras.AttributeMetadata": "4.0.0"
}
}
},
Given a test class with the following constructor:
public MyClass([WithKey("logging")] IRepository repository)
{
Repository = repository;
}
you would register everything in ConfigureServices (note the use of WithAttributeFilter():
containerBuilder.Register(c => new Repository("DEFAULT_CONNSTR")).Keyed<IRepository>("default");
containerBuilder.Register(c => new Repository("LOGGING_CONNSTR")).Keyed<IRepository>("logging");
containerBuilder.RegisterType<MyClass>().WithAttributeFilter();
I'm not sure if the title correctly describes my problem. If someone could better describe my problem by reading the following description, please help me by editing the title to something more meaningful.
I'm trying to learn asp.net MVC with Entity Framework and Ninject.
I was having a look at NuGet Gallery application on GitHub and tried to implement a few parts in my project.
I followed the answer provided in this question [How do architect an ASP.Net MVC app with EF?] and designed my project with the following layered structure.
MyDemoApp
MyDemoApp.Domain (Contains POCO Classes)
MyDomain.Service (Contains references to Domain,EF. It contains only Interfaces)
MyDemoApp.Data (Contains references to EF, Domain, Service. It contains classes dealing with Entity Context and Repository)
MyDemoApp.Web (Contains references to ApplicationModel,Data,Domain,Service,Ninject)
MyDemoApp.ApplicationModel (Contains references to Data, Domain, Serivce. It implements the classes from Service project)
MyDemoApp.Web has no business logic and is acting like Humble Object, as mentioned in this answer
I have a Interface IConfiguration in MyDemoApp.Service project which is being implemented by Configuration class located in MyDemoApp.Web where I'm trying to read the connection string. I need to pass this connection string to the object of EntityContext being created in EntityContextFactory located in MydemoApp.Data
If I add a project reference of MyDemoApp.web to MyDemoApp.Data then Visual Studio Prompts me saying that it would cause a circular reference
In the following code return new EntitiesContext(""); How should I pass a parameter over here that would get the connection string that my bindings.cs gets ?
namespace MyDemoApp.Data
{
public class EntitiesContextFactory : IDbContextFactory<EntitiesContext>
{
public EntitiesContext Create()
{
//TO-DO : Get the Connnectionstring
return new EntitiesContext(""); //Need to pass connection string by calling property from Configuration class in MyDemoApp.Web project
}
}
public class EntitiesContext:DbContext,IEntitiesContext
{
public EntitiesContext(string connectionString) : base(connectionString)
{
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
//Provide mapping like foreign key
}
}
}
}
Configuration.cs:
namespace MydemoApp.Web
{
public class Configuration : IConfiguration
{
public string ConnectionString
{
get
{
return ConfigurationManager.ConnectionStrings['dev'].ConnectionString;
}
}
}
}
Bindings.cs:
namespace MydemoApp.Web.Bindings
{
public class MyModule : NinjectModule
{
public override void Load()
{
Bind<IConfiguration>().To<Configuration>();
var configuration = new Configuration(); //Gives me Connectionstring
Bind<IEntitiesContext>().ToMethod(context => new EntitiesContext(configuration.ConnectionString)); // This part would help me pass the connection string to the constructor
}
}
}
I don't quite get what problem you are facing. I assume that you need to access a class in Web assembly from Data assembly, but Data assembly already referencing Web assembly.
Can you just inject the configuration interface to your factory constructor, and use that to get the connection string?
public class EntitiesContextFactory : IDbContextFactory<EntitiesContext>
{
public EntitiesContextFactory(IConfiguration configuration){
this.configuration = configuration;
}
IConfiguration configuration;
public EntitiesContext Create()
{
return new EntitiesContext(configuration.ConnectionString);
}
}
I may misunderstand your question though.
Personally, I think you should leverage the ConfigurationManager in your EntitiesContextFactory.
This would look like:
return new EntitiesContext(System.Configuration.ConfigurationManager.ConnectionStrings["{connectionstringname}"].ConnectionString)
This class is agnostic of whether it is an app.config or web.config that is providing the configuration.
All it stipulates is that application that is hosting the dlls for running, must be configured with an (app/web).config that contains that connection string. your app can test for this at startup since it knows it has a dependency on a database connection for it to work.
In the following example, what is an efficient way to implement multitenancy with minimal redundant code? In this scenario, tenant is a student. The students' school has 2 locations and each location is required to have the data (i.e, Courses) stored in a seperate database. When a student logs in, their location determines which database to pull from.
I'm using Entity Framework and Repository Pattern. Currently I have the implementation for accessing Location 1 DB. I've looked into different options to implement Location 2, such as injecting a TenantContext in the HomeController contructor, but I am stuck on how to set the correct database connection and what approach would be most efficient.
Below is the code for Location 1 only.
Example Controller
public class HomeController : Controller
{
ICourseRepository courseRepository;
//How to set the correct repository to use based on location?
public HomeController(ICourseRepository courseRepository)
{
this.courseRepository = courseRepository;
}
//Register for a new class
public ViewResult Register()
{
var courseList = courseRepository.AvailableCourses();
return View(courseList);
}
}
CourseRepository
public class CourseRepository : ICourseRepository
{
private Location1DB context = new Location1DB();
public List<Course> AvailableCourses()
{
//Get available courses from Location 1 Course Table
}
}
Location1Model.Context.cs (This is genereated using EF DbContext Generator)
public partial class Location1DB: DbContext
{
public Location1DB()
: base("name=Location1DB")
{
}
public DbSet<Course> Courses { get; set; }
}
Web.config
<connectionStrings>
<add name="Location1DB" ... />
<add name="Location2DB" ... />
</connectionStrings>
sorry I'll try to edit and provide a more complete answer when I get time tomorrow, but check this SO answer and the castle windsor container doco to get you started (also not sure what container you are using but all the major ones should have this functionality).
The thought would be to read the LocationID out of the cookie, grab the right connection string and have the container pass it as a parameter to your dbcontext.
DbContext is a partial class remember, so you could declare your own partial DbContext class, put an interface on it and pass that as a dependency into your repository.
I have an MVC4 Web API project and I making use of Mark Seemann's Hyprlinkr component to generate Uris to linked resources. (Customer -> Addresses for example).
I have already followed Mark's guide on Dependency injection with Web API (changing appropriately for Ninject) bit I can't quite work out what I should do to inject a IResourceLinker into my controllers.
Following Mark's guide my IHttpControllerActivator.Create create method looks like this:
IHttpController IHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
var controller = (IHttpController) _kernel.GetService(controllerType);
request.RegisterForDispose(new Release(() => _kernel.Release(controller)));
return controller;
}
It is in this method that the Hyprlinkr readme suggests to create the RouteLinker. Unfortunately I'm not sure how to register this with Ninject.
I can't just bind like below, as this results in multiple bindings:
_kernel.Bind<IResourceLinker>()
.ToMethod(context => new RouteLinker(request))
.InRequestScope();
I've got rebind working like this:
_kernel.Rebind<IResourceLinker>()
.ToMethod(context => new RouteLinker(request))
.InRequestScope();
But I'm concerned that changing the ninject binding graph is potentially a bad thing to do on every request.
What is the best way to achieve this?
Update following the request from Paige Cook
I'm using rebind here:
IHttpController IHttpControllerActivator.Create(HttpRequestMessage request, HttpControllerDescriptor controllerDescriptor, Type controllerType)
{
_kernel.Rebind<IResourceLinker>()
.ToMethod(context => new RouteLinker(request))
.InRequestScope();
var controller = (IHttpController) _kernel.GetService(controllerType);
request.RegisterForDispose(new Release(() => _kernel.Release(controller)));
return controller;
}
IHttpControllerActivator.Create is called on every request. The rest of the bindings are made in the standard way, by standard I mean in the class generated by using the Ninject.MVC3 nuget package.
My controller looks like this:
public class CustomerController : ApiController
{
private readonly ICustomerService _customerService;
private readonly IResourceLinker _linker;
public CustomerController(ICustomerService customerService, IResourceLinker linker)
{
_customerService = customerService;
_linker = linker;
}
public CustomerModel GetCustomer(string id)
{
Customer customer = _customerService.GetCustomer(id);
if (customer == null)
{
throw new HttpResponseException(Request.CreateResponse(HttpStatusCode.NotFound));
}
return
new CustomerModel
{
UserName = customer.UserName,
Firstname = customer.Firstname,
DefaultAddress = _linker.GetUri<AddressController>(c => c.Get(customer.DefaultAddressId)),
};
}
}
Register a delegate Function to give you the linker
_kernel.Bind<Func<HttpRequestMessage, IResourceLinker>>()
.ToMethod(context => (request) => new RouteLinker(request));
Inject the delegate
readonly Func<HttpRequestMessage, IResourceLinker> _getResourceLinker;
public controller(Func<HttpRequestMessage, IResourceLinker> getResourceLinker) {
_getResourceLinker = getResourceLinker;
}
Use in your actions
public async Task<Thingy> Get() {
var linker = _getResourceLinker(Request);
linker.GetUri( ... )
}
If you only need to use RouteLinker from ApiController derivates, you don't really need to go through all the DI hoops.
You can just create it within the Controller like this:
var linker = new RouteLinker(this.Request);
IMO, using DI with RouteLinker first becomes valuable when you need a RouteLinker further down the stack - but then again, I also only use RouteLinker as a Concrete Dependency...
Thanks for adding the code sample. Based on what you have posted, you are running into your Bind/Rebind issue because you are issuing the _kernel.Bind<IResourceLinker> in the IHttpControllerActivtor.Create method every time.
You need to move the _kernel.Bind<IResourceLinker> to be registered the same way your are registering the rest of your bindings in the
...standard way, by standard I mean in the class generated by using the Ninject.MVC3 nuget package.
There should not be any need for the IResourceLinker to be binded multiple times, and this is why you are getting multiple instances, because the binding is firing every time a controller is created by the IHttpControllerActivator.
Update:
Sorry that I missed the need for an HttpRequestMessage as a constructor argument, I would go with Anthony Johnson's answer on this one.
We have a site using Unity and IUnitOfWork for our EF context. Until now we've only been using a single EF Context so this is the one mapped in Unity config. This has all been handled through constructor injection and this is something we'd like to maintain for consistency.
We've now introduced another EF Context for our PaymentController that is used within the site but Unity config currently only allows us to create one type for IUnitOfWork.
I know that I can create a new <register/> element for the new context with a distinct name attribute but how do I implement this within the controller constructor to use the one named payments?
<register type="IUnitOfWork" mapTo="FirstContext" />
<register type="IUnitOfWork" mapTo="PaymentsContext" name="payments"/>
public class PaymentController()
{
public PaymentController(IUnitOfWork unitOfWork)
{
//How to I tell unity that this needs to be a payments
_unitOfWork = unitOfWork;
}
}
Many Thanks
When the FirstContext and PaymentsContext have each an unique set of entities (for instance, each connect to a different database) it is worth wild to explicitly define this in code. One way of doing this is by specifying a factory for each unit of work:
public interface IFirstContextFactory
{
IUnitOfWork CreateNew();
}
public interface IPaymentContextFactory
{
IUnitOfWork CreateNew();
}
public class PaymentController()
{
public PaymentController(PaymentContextFactory paymentContextFactory)
{
//How to I tell unity that this needs to be a payments
this.paymentContextFactory = paymentContextFactory;
}
public void DoSomething()
{
using (var context = this.paymentContextFactory.CreateNew())
{
// Do something useful
context.Commit();
}
}
}
Not only makes this your dependencies very clear (because you know what type of context the code is dealing with), but it also simplifies the DI configuration, because you won't need any named registrations.