When a user clicks the delete button (calls the delete method passing in the clientid).. i get the error: "Cannot add an entity with a key that is already in use".I dont know why this is happening and is really bugging me. the code for the controller is:
[Code]....
The code in my SqlClientsRepository.cs is:
[Code]....
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.
[Code]....
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
[Code]....
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'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?
View 3 RepliesI 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:
_event.InstallmentPlan = null;
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.
View 3 RepliesHere'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.
I am trying to do something like this:
[Code]....
But ofcourse it is not working as I want to. The Ordering works on Question.Order, but I would also the
Questions.SubQuestions List to be ordered according to SubQuestions.Order
Is there a way to export a EF 4.0 Data Model to EF 3.5?
I looked around and found that we are not able to access EF 4.0 from a ASP.Net 3.5 project here: [URL]
Our project is the 1st to go to .Net 4.0 using Entity Framework and we (the team) were wondering if there was a way for the other projects that "might" need to access our data that are still using the .Net 3.5 framework.
I'm using .Net 3.5 with SP1.
I'm not sure about the difference between entity name and Entity Set Name
I am new to entity framework , it is really very good , but I want to know what is the difference between using entity framework with stored procedure or without stored procedure , which one the faster and what is the benefits for using stored procedures with entity framework.
View 1 RepliesI'm having a bit of trouble trying to add an object to the database using LINQ to SQL.
I have three tables in my database:
--------------------------------------------
tblShows
--------------------------------------------
ShowID | Name
--------------------------------------------
--------------------------------------------
tblShowEvents
--------------------------------------------
ShowEventID | ShowID | Name
--------------------------------------------
--------------------------------------------
tblShowEventAttendees
--------------------------------------------
ShowEventAttendeeID | ShowEventID | Name
--------------------------------------------
A Show has many Events, and each Event has many Attendees.
I have a page where I'm creating a Show. On the page, I'm adding Events to the Show, and Attendees to each Event, and then saving the show all at once.
Here is my code:
Show show = new Show();
show.Name = txtName.Text.Trim();
//add ShowEvents to Show
//showEventsList is a variable containing a List of ShowEvents
foreach (ShowEvent ev in showEventsList)
{
show.ShowEvents.Add(new ShowEvent
{
ShowID = show.ShowID,
Name = ev.Name
});
}
//Add ShowEventAttendees to each ShowEvent
//attendeesList is a variable containing a List of ShowEventAttendees
foreach (ShowEvent ev in show.ShowEvents)
{
foreach (ShowEventAttendee attendee in attendeesList)
{
ev.ShowEventAttendees.Add(new ShowEventAttendee
{
ShowEventID = ev.ShowEventID,
Name = attendee.Name
});
}
}
AppDataContext.DataContext.Shows.InsertOnSubmit(show);
AppDataContext.DataContext.SubmitChanges();
The issue occurs in the second foreach loop. If I take it out, the Show and ShowEvents get added to the database correctly.
What's the issue here?
EDIT for Jay:
I've tried this now:
AppDataContext.DataContext.Shows.InsertOnSubmit(show);
AppDataContext.DataContext.SubmitChanges();
//Add ShowEventAttendees to each ShowEvent
//attendeesList is a variable containing a List of ShowEventAttendees
foreach (ShowEvent ev in show.ShowEvents)
{
foreach (ShowEventAttendee attendee in attendeesList)
{
ev.ShowEventAttendees.Add(new ShowEventAttendee
{
ShowEventID = ev.ShowEventID,
Name = attendee.Name
});
}
}
AppDataContext.DataContext.SubmitChanges(); //trying to update, error here
But I get the same error on that last line. Going through the debugger, ShowEventID is no longer 0, but I'm getting the same error.
I have a project with EF4 e poco templated entity. I need to delete a User entity that is associated via foreign key referential constraint to UsersinRoles and Profile entities in this way:
User 1:1 Profile
User 1:many UsersinRoles
On msdn I've found that: "When a primary key of the principal entity is part of the primary key of the dependent entity, then deleting the principal object also deletes all the loaded dependent objects. This is the same as defining the cascading delete rules on the relationship" So I can guess that deleting the User entity will delete the other two entities as well. so I call the delete method on user entity:
[Code]....
and the Usersinroles entities are deleted correctly instead of Profile that lives as an orphan in the db. what can I check to make it work correctly?
For each entity I am inserting to a SQL Server database through Entity Framework 4 I want to insert a corresponding logentry. These two insertions must be done in the same transaction. The problem is that the logentry record needs the id of the entity record, which is generated first when the entity record is inserted (with auto increment set to true on the primary key in the database).
[Code]....
I use the listview control a lot. I'm rewriting a website, and using the Entity Framework. I know how to use the EntityDataSource, but I would like to bind the listview in the code behind. if I have something like this:
Dim friend = (From f In context.prFriends _
Select f).FirstOrDefault
ListView1.DataSource = friend
ListView1,DataBind()
The above gives me the following error: Data source is an invalid type. It must be either an IListSource, IEnumerable, or IDataSource.
With LinqToSql I dould do
ListView1.DataSource = friend.toList
But that doesn't seem to be an option with Entity. How can I do this?
I'm using VS 2008 with SP1. I want to use SP in the entity framework. The SP uses join of more than 1 table to return data. Most of the online examples I show, use the single table. How to return data of more than one tables?
View 4 RepliesI ma trying to update a sql table using linq using the below code and i get the subject error.
[Code]....
solve this problemi create example using Northwind database so i create a new website and add new ADO.Net Entity Data Model (.edmx) called Northwind.edmx and i add Categories and Products table inside this (.edmx) fileand add new ADO.Net Data Servuce called "ADODataService" and add it as WebReferences called NorthwindServiceso i add new web page and drag DropdownList and Gridview as i want to bind Dropdownlist to all categories and when i select category from Dropdownlist bind Gridview to all Products related to this categoryso my code
[Code]....
and my code
[Code]....
so when i select category from Dropdownlist nothing happen :(also you will find commented code in method BindCategory whuch is not work also :(
What is the best way to cache an entity, so it can be used with linq ?
The following will not work.
using (EN myEN = new EN())
{
if (Cache.Get("CachPerson") == null) // Create Cache [code]....
i have been using entity framework in win app. but i notice i cant use it in web app. is there a different way to do it in web
View 1 RepliesI've been trying to learn about the entity framework. I plan on using it in a rewrite of a site I'm doing.But everything I can find on it is on the 3.5 framework and they all mention that there will be changes in 4.0. Does anyone know of a good article, video series, and or tutorial on the entity framework in 4.0?I've worked a lot with Linq to Sql, so I don't think I'll have too much trouble working with the entity framework, but I'd like to learn more about the current version.
View 3 Replies