I have just started working with .Net and I have created an Entity Framework Model and an associated context for the password reset functionality of a website and I have created this in a class library called MYSITE.Reset.Data with 3 classes (email,mapping,link).
I have now created a windows form application MYSITE.Reset but am having trouble in iterating through my models from the program.cs file. I am not quite sure of the structure of the syntax and I have unsuccessfully tried the following:
foreach(MYSITE.Reset.Data.Maps mp)
Try this:
var maps = from m in context.Maps
select m;
foreach(var map in maps)
{
// do stuff
}
Related
I have build a project using Microsoft Visual Studio 2015 and EntityFrameworkCore.
I have seed manually a couple of dummy data and I was developing my solution. Now, I want to deploy the in the server, but I get the problem that by starting the application the first time, it crash since it does not find a data base and data.
I have googled and I find the solution for Visual Studio 2013 and previous using the CreateDatabaseIfNotExists class that need the package: System.Data.Entity
(http://www.entityframeworktutorial.net/code-first/database-initialization-strategy-in-code-first.aspx), however, such classes and packages do not exist in EntityFrameworkCore.
How does I create and populate a database with at least one row if user is using my application by the first time in EntityFrameworkCore?
or which is the equivalent to System.Data.Entity in Entity Framework Core?
Rowan Miller says that ApplyMigrations is enough to create database (if not exist) and apply all (nesessary) migrations.
Create method like this:
public void CreateDbAndSampleData(IServiceProvider applicationServices)
{
using (var serviceScope = applicationServices.GetRequiredService<IServiceScopeFactory>().CreateScope())
{
using (var db = serviceProvider.GetService<ApplicationDbContext>())
{
// This will [try to] create database
// and apply all necessary migrations
db.Database.AsRelational().ApplyMigrations();
// then you can check for existing data and modify something
var admin = db.Users.Where(x => x.Name == "Superadmin").FirstOrDefault();
if (admin == null)
{
db.Users.Add(new User {...});
db.SaveChanges();
}
}
}
}
And call it from your Startup.cs, at end of Configure method:
CreateDbAndSampleData(app.ApplicationServices);
This code will run on every app startup, so you need to be accurate and do not overwrite any non-critical data changes (like changing Users's comment etc)
You can use MusicStore app as a sample: Startup.cs and SampleData.cs
Using an EF model in the Models folder in my MVC 4 project, I succeeded to display data in a razor view using a coded class named Prod and a controller method as next:
public ActionResult Index()
{
IEnumerable<Prod> Pr = from p in db.Products
select new Prod
{
ProductId = p.ProductID,
ProductName = p.ProductName
};
return View(Pr);
}
Now I am trying to do the same thing using a model in a class library instead of the current one, so I added to my solution a new class library, added then a model using the same connection string, and mapping the same entities, then added to my MVC project a reference to the new class library, and put at the top of both MyController and Prod class the next:
using MyClassLibrary;
Then I deleted the old model, now when I try to display the view, I get the following error:
Unable to load the specified metadata resource.
Any help please ?
When you move or rename the project the data context (.edmx) is in the metadata part of the Entity Framework connection string has to change
you can try have
connectionString="metadata=res://*/MyModel.csdl|res://*/MyModel.ssdl|res://*/MyModel.msl;
instead of
connectionString="metadata=res://*/Models.MyModel.csdl|res://*/Models.MyModel.ssdl|res://*/Models.MyModel.msl;
or try deleting your context and recreating it then check the connection string it adds automatically.
You need to put your connectionstring in web.config in Mc4 web project
You need to Mention the datasource in the connection string.
If you have not used any other web.config file for views. Use you generic web.config file and upload a connection string with New datasource name , user and password.
How do set up autoloading with Doctrine 2 and Zend to load entities in the following directory structure:
Application
-Modules
--Core
---Models
----Entities
----Repositories
--CMS
---Models
----Entities
----Repositories
I want to be able to load classes using {ModuleName}\Entities{EntityName}. For example, I'd like to be able to do this to load a 'User' entity:
$em->getRepository('Core\Entities\User');
or something like this for a 'Pages' entity:
$em->getRepository('CMS\Entities\Pages');
I can set it up to load 'CMS\Models\Entities\Pages' but I'd like to be able to know how to do it without having to map directly to the directory structure. Is this possible?
I don't how you glue Zend Framework and Doctrine2 together but if you are using the popular Bisna glue (which is pretty cool) you can set-up more than one mapping directory in your application.ini. Take a closer look to the following ini settings:
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.0.adapterClass = "Doctrine\ORM\Mapping\Driver\AnnotationDriver"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.0.mappingNamespace = "Core\Entities"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.0.mappingDirs[] = APPLICATION_PATH "/modules/Core/Entities"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.0.annotationReaderClass = "Doctrine\Common\Annotations\AnnotationReader"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.0.annotationReaderCache = default
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.1.adapterClass = "Doctrine\ORM\Mapping\Driver\AnnotationDriver"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.1.mappingNamespace = "CMS\Entities"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.1.mappingDirs[] = APPLICATION_PATH "/modules/CMS/Entities"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.1.annotationReaderClass = "Doctrine\Common\Annotations\AnnotationReader"
resources.doctrine.orm.entityManagers.default.metadataDrivers.drivers.1.annotationReaderCache = default
Something like the above would be accomplish what you want. If want to be able to do this fully automatically I think you have to patch the Bisna\Doctrine\Container class. Which for instance looks to the modules defined check if there is a entities directory and add's this to the doctrine entity manager.
Bisna
If you don't have a clue what Bisna is, this is a small library which allows you to easily 'glue' Doctrine2 and Zend Framework 1 together.
By watching this video it should be easy for you to understand how to integrate Doctrine2.
http://www.zendcasts.com/unit-testing-doctrine-2-entities/2011/02/
Please be aware that the Bisna version used in the video only supports Doctrine 2.0 and not 2.1 in that case you should use this one: https://github.com/guilhermeblanco/ZendFramework1-Doctrine2
EF CTP 5. I have a single instance where I would like to get the unproxied entity. I can't seem to find a way to do this. I don't want to disable proxy creation all together, just need it for this one query. Can anyone help?
Here is a simple example:
var myEntity = DbContext.Entities.Find(1);
var unproxy = myEntity...?
I believe the only possibility is to create new instance of DbContext and turn proxy creation off just to execute this query. The reason is that DynamicProxy is type created in runtime which derives from your original entity type and adds tracking and lazy loading functionality. You can't strip the proxy away once you created it this way. Try this:
using (var context = new MyDbContext(connectionString))
{
((IObjectContextAdapter)context).ObjectContext.ContextOptions.ProxyCreationEnabled = false;
var myEntity = context.Entities.Find(1);
}
In Asp.Net Core you can use AsNoTracking().
Eg:
var blogs = context.Blogs
.AsNoTracking()
.ToList();
More info you can find here.
I'm using AutoMapper to map between a Linq Domain object and a ViewModel to display an Edit Form to the user which works perfectly.
When they click submit I'd like to know the best way to map the ViewModel back to a Linq entity and persist it to the database.
The Linq entity I'm using has multiple collections of other entities (ie one-to-many references).
I was trying:
build up my custom view model using UpdateModel
get the previous state of the Linq entity by using the passed in id
map the view model onto the Linq entity (using automapper)
call SubmitChanges() on the data context
This method works when I'm only updating properties that are not collections, but throws errors when trying to modify properties that are collections.
Any help/thoughts would be much appreciated :)
I've taken an approach that is very similar to that used by Jimmy Bogard in the CodeCampServer project (http://codecampserver.codeplex.com/)
I have a general Mapper class that I inherit from where I just need to override a MapToModel method that maps from the ViewModel to the domain Model, and a GetIdFromViewModel method that returns the proper Id form the ViewModel so that the Service layer can grab the domain model from the database.
I had to change a little from the CodeCampServer examples because some of my Models used Guid and some used int as the Id for the Model.
You should be able to grab the code from the codeplex link above and that should help get you going in that direction.
Here is what one of my Mappers for a Member looks like:
public class MemberMapper : AutoFormMapper<Member, MemberFormViewModel, Guid>, IMemberMapper
{
public MemberMapper(IMemberService service) : base(service) { }
protected override Guid GetIdFromViewModel(MemberFormViewModel viewModel)
{
return viewModel.MemberId;
}
protected override void MapToModel(MemberFormViewModel viewModel, Member model)
{
// if the need arises, we will need to map the full objects as Foreign Key properties
// by using the proper repositories
// right now for loading the object to save back to the DB we don't have that need, so let's not waste the call
model.MemberId = viewModel.MemberId;
model.FirstName = viewModel.FirstName;
model.LastName = viewModel.LastName;
model.Title = viewModel.Title;
model.EmailAddress = viewModel.EmailAddress;
model.DirectPhone = viewModel.DirectPhone;
model.MobilePhone = viewModel.MobilePhone;
model.ElectronicId = viewModel.ElectronicId;
model.ProjectRoleTypeId = viewModel.ProjectRoleTypeId;
model.DepartmentId = viewModel.DepartmentId;
}
}
Then you can use this MemberMapper to map both directions. It uses AutoMapper to go from the domain Model to the View Model and then uses the MapToModel method that you implement to map from the View Model back to the domain Model.