I have a model that looks kinda like this:
public class Notes
{
public int NoteID {get; set;}
public string Note {get; set;}
public int CustomerID {get; set;}
{
On the Notes Details view, I would like to be able to show Customer Name instead of CustomerID. Obviously if this were a Create or Edit view I use a dropdown list.
However I am not sure how to show the value and not the ID in a read only Details view.
Thanks!
Code First is mainly... code, not Database logic.
So, instead of having the Foreign Keys (like CustomerID) in your models (it's also possible, and sometimes needed, but not always), you'll be more confortable having a reference property
public virtual Customer Customer {get;set;}
So in your view having Notes as Model, you could simply use
#Html.DisplayFor(m => m.Customer.Name);
When you retrieve your Notes entity, don't forget to include the related entities / properties needed for your View / ViewModel (I let you read about lazy loading)
You can try this:
var applicationDbContext = _context.Notes.Include(n => n.Custumer);
return View(await applicationDbContext.ToListAsync());
This code must be in your controller, in the Index method or whatever you named it.
And this is in view.
#Html.DisplayFor(modelItem => item.Customer.Name)
Related
Following this article (What are best practices for multi-language database design?), I have all my database tables splitted in two: the first table contains only language-neutral data (primary key, etc.) and the second table contains one record per language, containing the localized data plus the ISO code of the language. The relationship between the two tables is one to many.
Here a screenshot of the datamodel: https://dl.dropboxusercontent.com/u/17099565/datamodel.jpg
Because the website has 8 languages, for each record in table "CourseCategory" I have 8 record in table "CourseCategoryContents". The same happens with "Course" and "CourseContent"
Then I use Entity Splitting in order to have only one entity for the Course Category and one entity for the Course:
public class CourseCategoryConfiguration : EntityTypeConfiguration<WebCourseCategory>
{
public CourseCategoryConfiguration()
{
Map(m =>
{
m.Properties(i => new { i.Id, i.Order, i.Online });
m.ToTable("CourseCategories");
});
Map(m =>
{
m.Properties(i => new { i.LanguageCode, i.Name, i.Permalink, i.Text, i.MetaTitle, i.MetaDescription, i.MetaKeywords });
m.ToTable("CourseCategoryContents");
});
}
}
public class CourseConfiguration : EntityTypeConfiguration<WebCourse>
{
public CourseConfiguration()
{
Map(m =>
{
m.Properties(i => new { i.Id, i.CategoryId, i.Order, i.Label, i.ThumbnailUrl, i.HeaderImageUrl });
m.ToTable("Courses");
});
Map(m =>
{
m.Properties(i => new { i.LanguageCode, i.Name, i.Permalink, i.Text, i.MetaTitle, i.MetaDescription, i.MetaKeywords, i.Online });
m.ToTable("CourseContents");
});
}
}
Then to retrive the courses in a desired language including their category I do this:
using (WebContext dbContext = new WebContext())
{
// all courses of all categories in the desired language
return dbContext.Courses
.Include(course => course.Category)
.Where(course => course.LanguageCode == lan
&& course.Category.LanguageCode == lan)
.ToList();
}
}
Entity splitting works fine with one-to-one relationships, but here I have one-to-many relationships.
The website has contents (CourseCategories and Courses) in 3 languages ("en", "de", "fr").
EF correctly returns all the Courses with their Category in the right language (eg. in english), but returns each record 3 times. This is because I have the CourseCategory in 3 languages too.
The only one working solution I came up is avoiding using ".Include(Category)", getting all the courses in the desired language in first, then, in a foreach cycle, for each Course retriving its Category in language. I don't like this lazy loading approach, I would like to retrive all the desired data in one shot.
Thanks!
The best solution is to map tables to the model as it then in your model Course class will have a navigation property ICollection<CourseCategoryContent>.
In this case you just project this model to DTO or ViewModel "according to your application design"
e.g.
Your model will look like this
public class Course
{
public int Id {get; set;}
public int Order {get; set;}
public ICollection<CourseCategoryContent> CourseCategoryContents {get; set;}
}
public class CourseCategoryContent
{
public string LanguageId {get; set;}
public string Name {get; set;}
}
Then just create new DTO or ViewModel like :
public class CourseDTO
{
public int Id {get; set;}
public int Order {get; set;}
public string Name {get; set;}
}
Finally do the projection
public IQueryable<CourseDTO> GetCourseDTOQuery ()
{
return dbContext.Courses.Select(x=>new CourseDTO{
Id = x.Id,
Order = x.Order,
Name = x.CourseCategoryContents.FirstOrDefault(lang => lang.LanguageId == lang).Name,
});
}
And note that the return type is IQueryable so you could do any filter, Order or grouping operation on it before hitting the database.
hope this helped
No fix-all answer i'm afraid, every way has a compromise.
I've used both the database approach (10+ language dependent tables) and the resource file approach in fairly large projects, if the data is static and doesn't change (i.e you don't charge a different price or whatever) I would definately consider abstracting language away from your database model and using Resource keys then loading your data from files.
The reason or this is the problem you are experiencing right now where you can't filter includes (this may have changed in EF6 perhaps? I know it's on the list of things to do). You might be able to get away with reading it into memory and filtering them though like you're doing but this meant it wasn't very performant for us and I had to write Stored Procedures that I just passed the iso language and executed in EF.
From a maintenance point of view it was easier as well, for the DB project I had to write an admin console so people could log on and edit values for different languages etc. Using resource files I just copy-pasted the values into excel and emailed them to the people we use to translate.
It depends on the complexity of your project and what you prefer, i'd still consider both approaches in future.
TLDR: options that i've found are:
1) filter in memory
2) lazy load with filter
3) write stored procedure to EF and map that result
4) use resources instead
Hope this helps
EDIT: After looking at diagram it looks like you may need to search against the language dependant values? In that case resources probably won't work. If you're just letting them navigate off a menu then you're good to go.
Earlier today, a helpful person (here on Stack Overflow) pointed me towards AutoMapper, I checked it out, and I liked it a lot! Now however I am a little stuck.
In my Code First MVC3 Application, on my [Home/Index] I need to display the following information from my Entities:
List of Posts [ int Id, string Body, int Likes, string p.User.FirstName, string p.User.LastName ]
List of Tags [int Id, string Name]
List of All Authors that exist on my Database [ string UrlFriendlyName ]
So far I have managed only point 1 in the list by doing the following for my Index ViewModel:
public class IndexVM
{
public int Id { get; set; }
public string Body { get; set; }
public int Likes { get; set; }
public string UserFirstName { get; set; }
public string UserLastName { get; set; }
}
And on the Home Controller, Index ActionMethod I have:
public ActionResult Index()
{
var Posts = postsRepository.Posts.ToList();
Mapper.CreateMap<Post, IndexVM>();
var IndexModel = Mapper.Map<List<Post>, List<IndexVM>>(Posts);
return View(IndexModel);
}
Finally on my View I have it strongly typed to:
#model IEnumerable<BlogWeb.ViewModels.IndexVM>
And I am passing each Item in the IndexVM IEnumberable to a Partial View via:
#foreach (var item in Model)
{
#Html.Partial("_PostDetails", item)
}
My question is, how can I also achieve point 2 and 3, whilst not breaking what I've achieved in point 1.
I tried putting the stuff I currently have for IndexVM into a SubClass, and having a List Property on the Parent class, but it didn't work.
From the ASP.NET MVC2 In Action Book:
Some screens are more complex than a single table. They may feature
multiple tables and additional fields of other data: images, headings,
subtotals, graphs, charts, and a million other things that complicate
a view. The presentation model solution scales to handle them all.
Developers can confidently maintain even the gnarliest screens as long
as the presentation model is designed well. If a screen does contain
multiple complex elements, a presentation model can be a wrapper,
composing them all and relieving the markup file of much complexity. A
good presentation model doesn’t hide this complexity—it represents it
accurately and as simply as possible, and it separates the data on a
screen from the display.
Make a ViewModel that represents your screen. Then build it up and pass it to the View. This book is great and talks about using a presentation model. With AutoMapper, think about how you would accomplish your mapping without it, then make use of it. AutoMapper isn't going to do anything magic, it eliminates keyboard slapping.
AutoMapper aside, take your list of requirments:
List of Posts [ int Id, string Body, int Likes, string p.User.FirstName, string p.User.LastName ]
List of Tags [int Id, string Name]
List of All Authors that exist on my Database [ string
UrlFriendlyName ]
and assuming you have these Model entites: Post, Tag, Author
Personally I don't like passing Model entities to my presentation in MVC or MVVM but that's me. Say we follow that here and create PostDisplay, TagDisplay, and AuthorDisplay.
Based on the View's requirements the ViewModel will look like this:
Public class IndexVM
{
Public List<PostDisplay> Posts {get; set;}
Public List<TagDisplay> Tags {get; set;}
Public List<AuthorDisplay> Authors {get; set;}
}
In this case the way the View is composed will require you to build it up:
public ActionResult Index()
{
var posts = postsRepository.Posts.ToList();
var tags = postsRepository.Tags.ToList();
var authors = postsRepository.Authors.ToList();
Mapper.CreateMap<Post, PostDisplay>();
Mapper.CreateMap<Tag, TagDisplay>();
Mapper.CreateMap<Author, AuthorDisplay>();
private var IndexVM = new IndexVM
{
Posts = Mapper.Map<List<Post>, List<PostDisplay>>(posts),
Tags = Mapper.Map<List<Tag>, List<TagDisplay>>(tags),
Authors = Mapper.Map<List<Author>, List<AuthorDisplay>>(authors)
};
return View(IndexVM);
}
So, what you end up with is a ViewModel to pass to your view that represents exactly what you want to display and isn't tightly coupled to your Domain Model. I can't think of a way to have AutoMapper map three separate result lists into one object.
To clarify, AutoMapper will map child collections so a structure like:
public class OrderItemDto{}
public class OrderDto
{
public List<OrderItemDto> OrderItems { get; set; }
}
will map to:
public class OrderItem{}
public class Order
{
public List<OrderItem> OrderItems { get; set; }
}
As long as you tell it how to map the types: OrderDto -> Order and OrderItemDto -> OrderItem.
As an alternative to including all of your lists of entities on a single viewmodel, you could use #Html.Action. Then, in your screen view:
#Html.Action("Index", "Posts")
#Html.Action("Index", "Tags")
#Html.Action("Index", "Authors")
This way, your Index / Screen view & model don't need to know about the other viewmodels. The partials are delivered by separate child action methods on separate controllers.
All of the automapper stuff still applies, but you would still map your entities to viewmodels individually. The difference is, instead of doing the mapping in HomeController.Index(), you would do it in PostsController.Index(), TagsController.Index(), and AuthorsController.Index().
Response to comment 1
public class IndexVM
{
// need not implement anything for Posts, Tags, or Authors
}
Then, implement 3 different methods on 3 different controllers. Here is one example for the PostsController. Follow the same pattern for TagsController and AuthorsController
// on PostsController
public PartialViewResult Index()
{
var posts = postsRepository.Posts.ToList();
// as mentioned, should do this in bootstrapper, not action method
Mapper.CreateMap<Post, PostModel>();
// automapper2 doesn't need source type in generic args
var postModels = Mapper.Map<List<PostModel>>(posts);
return PartialView(postModels);
}
You will have to create a corresponding partial view for this, strongly-typed as #model IEnumerable<BlogWeb.ViewModels.PostModel>. In that view, put the HTML that renders the Posts UI (move from your HomeController.Index view).
On your HomeController, just do this:
public ActionResult Index()
{
return View(new IndexVM);
}
Keep your view strongly-typed on the IndexVM
#model IEnumerable<BlogWeb.ViewModels.IndexVM>
... and then get the Posts, Tags, and Authors like so:
#Html.Action("Index", "Posts")
Response to comment 2
Bootstrapping... your Mapper.CreateMap configurations only have to happen once per app domain. This means you should do all of your CreateMap calls from Application_Start. Putting them in the controller code just creates unnecessary overhead. Sure, the maps need to be created - but not during each request.
This also helps with unit testing. If you put all of your Mapper.CreateMap calls into a single static method, you can call that method from a unit test method as well as from Global.asax Application_Start. Then in the unit test, one method can test that your CreateMap calls are set up correctly:
AutoMapperBootStrapper.CreateAllMaps();
Mapper.AssertConfigurationIsValid();
I'm using MVC3 with Razor views and would like to build reusable DropDownLists for several of my classes, but after much searching I have not found an example that performs exactly how I need it...
For this example I have two classes like this:-
public class Person
{
public int ID { get; set; }
public string Name { get; set; }
public Group Group { get; set; }
}
public class Group
{
public int ID { get; set; }
public string Name { get; set; }
}
I have a working Controller/View for Person. The view has a DropDownListFor control:
#model Person
...
#Html.DropDownListFor(o => o.Group.ID, (ViewData["groups"] as SelectList))
The view uses the Person class directly, not an intermediary model, as I haven't found a compelling reason to abstract one from the other at this stage.
The above works fine... in the controller I grab the value from Group.ID in the Person returned from the view, look it up, and set Person.Group to the result. Works, but not ideal.
I've found a binder here: MVC DropDownList values posted to model aren't bound that will work this out for me, but I haven't got that working yet... as it only really seems useful if I can reuse.
What I'd like to do is have something like this in a template:-
#model Group
#Html.DropDownListFor(o => o.Group.ID, (ViewData["groups"] as SelectList))
And use it in a view like this:-
#Html.EditorFor(o => o.Group)
However the above doesn't seem to work... the above EditorFor line inserts editors for the whole class (e.g. a textbox for Group.Description as well)... instead of inserting a DropDownList with my groups listed
I have the above template in a file called Group.cshtml under Views/Shared/EditorTemplates
If this worked, then whenever a class has a property of type Group, this DropDownList editor would be used by default (or at least if specified by some attribute)
Thanks in advance for any advice provided...
You can create a drop down list user control to handle this. Under your Shared folder create a folder called EditorTemplates and place your user control there. MVC, by convention, looks in the Shared/EditorTemplates for any editor templates. You can override where it looks for the editor templates but I won't go in to that here.
Once you have your user control created, you'll need to decorate the appropriate property with the "UIHint" attribute to tell the engine what editor it should use for that property.
Following would be a sample implementation.
In the Shared/EditorTemplates folder your user control (_GroupsDropDown.cshtml in this case) would look like:
#model Group
#Html.DropDownListFor(o => o.ID, (ViewData["groups"] as SelectList))
Modify the Group property in the Person to add the UIHint attribute as follows:
**[UIHint("_GroupsDropDown")]**
public Group Group { get; set; }
In your controller you would need
ViewData["groups"] = new SelectList(<YourGroupList>, "ID", "Name");
Once you have the above code you can use the EditorFor syntax like you desire.
Hope this helps.
I'm working with a Razor MVC3 project
I have a model
public class ProductFormatModel
{
public int ID {get; set;}
public string SerialID { get; set; }
public ProductTypes ProductType { get; set; }
public List<ProductComponent> Components { get; set; }
}
The ProductComponent class has two properties: int ID and string Description.
I would like the controller to work with a strongly typed view of ProductFormatModel type to create a new ProductFormatModel. The Create view should look like this:
A textfield to insert SerialID (done)
A dropdownlist to select the value of the enumerator ProductType (done)
A listbox with different rows showing the "Description" property of ProductComponent. Every row should present a record in the database. The user must be able to select one or more rows and in this way the property "Components" should have those objects in the list.
The database is a simple DbContext. MyDB.Components gives me the recordset of table "Components"
How do I pass the values of the recordset from the controller to the view?
Should I call a listboxfor with multiselectlist?
Should I add another property to the model like List ComponentsToBeSelected in which I can pass the list?
One possible design:
Use two listboxes in your view. Load the first with all possible ProductComponents that are not in model.Components, and use ListBoxFor to bind the second to the model.Components list.
Place two buttons, Add and Remove, between the lists. Wire these up with jQuery to move items between the two listboxes.
Hi there I am hoping someone can point me in the right direction.
I want to create an mvc applicaton I have worked my way through the music store example and still am not 100% sure the correct way to do things.
Lets say I want to create an application that stores cooking receipes.
I have a 3 tables
RecipeTable
RecipeID
RecipeName
RecipeIngredients
RecipeIngredientID
RecipeID
IngredientID
Measurement
IngredientTable
IngredientID
IngredientName
All have PK & FK mappings very basic, I create a new mvc application and use the entity framework to create a new entity e.g. RecipeDB
My next step is I create a new model for each of the tables and give the properties my desired displaynames and specify required fields extra.
Do I then create a viewmodel e.g. RecipesViewModel that looks something like
public class RecipesViewModel
{
public int RecipeID { get; set; }
public string RecipeName { get; set; }
public List<RecipeIngredients> { get; set; }
}
I now create the controller (Ithink) but I am not really sure how to bind that to database entity.
I know you can call the database by doing something like RecipeEntities db = new recipeEntites(); however binding the results to the vm I am little confussed on how to do that.
Am I heading in the right direction so far?
You could use AutoMapper. It's a great tool allowing you to convert from one type to another and in your case from the model to the view model.
public ActionResult Foo()
{
RecipeDB model = _repository.GetRecipies();
RecipesViewModel viewModel = Mapper.Map<RecipeDB, RecipesViewModel>(model);
return View(viewModel);
}
or you could even define a custom action attribute (like the one I used in my sample MVC project) allowing you to simply write:
[AutoMap(typeof(RecipeDB), typeof(RecipesViewModel))]
public ActionResult Foo()
{
RecipeDB model = _repository.GetRecipies();
return View(model);
}