Are there any good tutorials that show how to build and maintain entity models from scratch manually. The visual builder it comes with it quite buggy and pretty much useless. If I make a change in the database and then try to update model from database in the .edmx file, it does not work properly (like making a field Nullable). I have to completely delete and then re-generate that file again and I am not going to be doing that every single time I make a database change so I need to know how to build and maintain these classes manually. Note that I need the C# version, not VB.
I am using Visual Studio 2010 now. I do not have network access to my database because of some connectivity issues. Are there any good articles on how to manually wireup Entity Framework objects manually? Or, is this just unrealistic?
I then retrieve the data from the DataTable into an anonymous type:
var feeds = from feed in categoryProducts.AsEnumerable()[code]....
This all works great.
However, I would like to extend the code to perform some evaluation checks (e.g., check that various columns in the DataTable are not NULL) and other pre-processing (e.g., call various functions to build the image URL based on the image ID - which is another column in the DataTable not shown in the code fragment) before I return the resulting rows of the DataTable as an anonymous type to the client-side.Basically, I want to iterate through the DataTable, perform the evaluation checks and pre-processing, while building my anonymous type manually as I go. Or maybe there is a better way to achieve this?
Is there a way to manually update a single edmx entity to reflect a new column in a SQL db table? If yes, what would be the proper step- by-step procedure?
I prefer not to use the "update model from db" template because this will update all the tables and wipe out all the customizations and name changes I have already made in the EF objects. This seems a bit overkill for a single column change. I went down this route once, and I prefer not to do it again. I do not see any way to actually update a single table from the DB using VS2010 "update from db".
What I have tried to do so far is manually add a new scalar property to the appropriate entity using the edmx designer, and this seems to work OK, but I cannot seem to find a way to map the new property back to the db through the mapping window. Do I have to do this directly through the XML file? Also is this sufficient to ensure the new column is correctly reflected in the edmx, or are there other steps that need to be done?
I have an EDM, it includes the entities extension and history. My goal is to use history to keep track of all the changes made to extension entity. For example, if extension with ID 223 has its property 'Name_Display' changed - I want the history entity to record this.
I'm using ASP.NET with VB.NET. Where in my code do I put the hook to say, "update the history entity" and what should that hook look like?
getting data from multiple Entities models into an MVC controller. Most of the examples I have seen for using EF in an MVC2 app only use a single entitiy.
I have just started using MVC2 in C# using the Entity Framework models (CIOps.model) created from an SQL database. I can create the controller and views using single tables of the model in MVC2, but I just cannot get my head around how to get data from multiple entity tables into the controller (similar to joins in T-SQL). I have included an example below of the controller code that works with a single entity table, tbl_tours (tbl_tour in DB).
Could someone please illustrate how this code would be changed to include additional columns from FK tables in addition to tbl_tours columns. E.g. the clients name from the tbl_clients, the coordinators name from the tbl_employees, and costs from tbl_costs entities? Is it possible to do this directly using the EF model entities/classes that are already created and not use LINQ, POCO, Repositories, etc.? The FK relationships are already in the EF models. I have included the whole controller code, but I just need a few examples of how to join the multiple entities, not rewrite every CRUD function function in the controller. I think this will get me over the hump in using EF in an MVC2 App. Also ignore the fact I am using the home controller, this will change in the application.
I get an cast exception when i am trying to insert an entity in Entity Framework (using code-first). From this code :
public virtual T Insert(T entity) { return Context.Set<T>().Add(entity); }
The cast exception is like "impossible to cast ...Collection'1(Entity) to type (Entity)" I can't figure out why. I am pretty sure ive done everything right. Post entity
public class Post { public long PostId { get; private set; } public DateTime date { get; set; } [Required] public string Subject { get; set; } public User User { get; set; } public Category Category { get; set; } [Required] public string Body { get; set; } public virtual ICollection<Tag> Tags { get; private set; } public Post() { Category = new Category(); if (Tags == null) Tags = new Collection<Tag>(); }................................
I am mapping a stored procedure to an entity by right clicking on the entity (in the .edmx) and selecting "Stored Procedure Mapping." This brings you to a Mapping Details - "Name of Entity" Window that allows you to select the insert, update, and delete stored procedures associated with the Entity. It also maps the stored procedure parameter to the Entity "Property" (Column).
I'm gettin an error "error 2042: Parameter Mapping specified is not valid." The cause of the error is fairly obvious, in the Insert stored procedure that has been selected, a 'CHAR' parameter is being mapped to an Int32 Entity Property. I altered the stored procedure parameter to match the entity, I deleted the stored procedure, readded, and reslected it as the Insert function. I also cleaned, validated, updated model from database. No matter what I do, the parameter list in the mapping details doesn't reflect the change to the stored procedure. It's stuck on a char --> int32 mapping, even though it has been changed, like it's buried deep in meta data some where.
I am trying to add a new entity and have to refernce associated data to add it. I cannot load the Referencetables. Giving "The EntityReference could not be loaded because it is not attached to an ObjectContext." How do i complete this task in Entity Framework 3.5
I have a stupid problem with the Entity Framework. I get the following Exception:
[Code]....
I have an entity with a 4 fields representing the primary key. I copy it via serialization (works fine). I set the old entity to not valid (Datefield set to a date in the past, this field is part of the PK) and set the copied entity to DateTime.Now.Date. When I call context.AddObject I get the Exception above. I tried copying the entity via reflection but the entity has 3-4 references. And when copied, I get another Exception before even Adding the entity to the context. I also tried setting newObj.EntityKey = null and reset all the fields neccessary for the PK. I just want a whole copy of an entity with a different primary key (and some other fields changed too) and Create it in the database.
I have been searching for this answer and can't seem to find anything, but with EF4 I want to create a base model and put in our 'foundation' and any new project we create if we need to add custom tables to that sites db is it possible to add a model with just those specific tables and link it to the model in our 'foundation' I can't seem to find a good resource on something like this and this seems to be like it would be a normal thing to have a reusable base model and a separate one for any one off's
How do I display more than one model per view? The above line limits me to only display UserProfiles. I want to also display other models, like UserJob and etc....how would I go about doing so?
I created a model via adding an ADO.Net Entity Data Model (.edmx file), which brought in all my tables from my database. Is it possible to add validation attributes like [Required] or [Display] to a model created like this? Otherwise, the only alternative I can see is to hand-create a model class with public properties where I can annonate them with the attributes I need.
I want to use RenderPartial twice in my view with different models associated. The problem is that some properties are present in both models (nickname, password). They have no prefix, so even the id's or names are equal in the output. Now, if I have model errors for nickname or password, both fields get highlighted.
I'm trying to develop my application and I've got a master page where I'm planning to create a div container, where my "news" will be loaded from my database and will be shown always on a main site. Then inside of the main placeholder I'm planning to load some extra data too from my database... and there's the question: how to solve that ? is there any possibility to pass a model to a master page ? or two viemodels to a view page inside the main placeholder on my page ? (one with news, and other containing some other data).
In some of the classic descriptions of MVC, the Model notifies Views via the observer pattern. It seems to me that this doesn't happen with ASP.NET MVC, and so one of the fundamental relationships between Model, View, and Controller is missing.
And the the partial view "Person" has an other model:[Code].... If I press the "Submit-Button" on the first view I get to the follwing controler: [Code]....
I've half written an app which has just one model for adding and editing a particular entity.I am trying to embrace modelmetadata and where possible reduce my form code to just calls for EditorForModel. One of the key issues I am having it managing the differences between a add and update scenario.
Take "User" editing for example, in an Add scenario I want "Password" to be a required field, in an update scenario I dont' want it to be a required field. The model-centric approach would have me create two models, one for adding and one for editing. My edit model wouldn't have the Required attribute on the Password field. My feeling is this is going to create a bit too much plumbing.
Besides having a rather massive amount of automapping going on there is another more irrititating issue. Strongly typed views. I could... maybe see my way to having a different model for create and edit, using inheritance i could.. maybe mitigate the amount of code required. What I can't abide is having to have two seperate views, as I have already coding myself into a wall with strongly typed views I couldn't share add and edit (based on my understanding) scenarios with one view.
So anyway I was wondering what other peoplle are doing to manage this? Working with an outsourced (Indian) developers it would be great to make use of EditorForModel as I want them writing as little code as possible.
I'm writing a custom .NET MembershipProvider (not the built in one) and trying to update using Entity Framework. But of course i have no access to (Try)UpdateModel. How can i update it?
I have an Events table and an InstallmentPlans table. The relationship is 0..1 : an Event can have 0 or 1 Installment plans. If I want to remove the existing InstallmentPlan for an event, how do I do this? Setting it to null doesn't seem to work:
Does ASP.NET provide any built in functionality for converting a named entity into its corresponding entity number? For example, I want to convert to , " to " and so on.
Here's a simple code snippet where I create a new Entity object and call SaveChanges() to create a new record in the mapped database table.
[Code]....
What I'm trying to figure out is whether there is a way to derive this new key for my entity, e, from the ObjectContext, m? The reason for this is that the way my actual code is structured, my entity object is already out of scope at the point where I call the SaveChanges() method.
