I have implemented a simple repository pattern for the Entity Framework in a web app.
I have several repositories which all subclass a base which has some common methods in The base looked like this
[code]....
So this appears to have solved my problem, but I am concerned that the scope of RedirectsEntities is now incorrect.
Probably these are two questions in one, I am using one EF context per request, but I want to use one per thread, because I am going to make some complex task in another thread during the request. So, is it safe? If the answer is yes, how to do it? how to store objects in thread and get them back?
View 2 RepliesI have some Data returning from a Context. Data has being pulled by spCmsCategoriesReadHierarchy.
I need take all Data from Context and populate my DataSet. My final goal is to populate a TreeView Control with DataSet object.
[code].....
I ran into this problem using EF4 and a self-referential table (implementing an adjacency list hierarchy). NOTE: not a many-to-many reference, just a one-to-many on a single table. Attempts to resolve an intermittent InvalidOperationException ("...The ObjectContext might be in an inconsistent state...") using Context.Refresh fail due to an apparent bug in EF4. I saw, from following Shimmy's connect.microsoft.com link, on the aforementioned post, that the bug is still outstanding. Can anyone recommend a workaround? What do you do if your database and Entity Framework get out of sync?
When I get the InvalidOperationException and the message says "The changes to the database were committed successfully...", it is not true. They weren't. I tried to change an object's ParentId from 1 to null (ParentId of type int?). My object's ParentId attribute is correctly changed to the expected value (null). I call Context.SaveChanges(). Then, the exception is thrown. I check the DB, and the value has not been updated. In this case, ParentId is still 1 in the database...................
I'm working on a project which is using EntityFramework 4 and I am using the entity objects as my business objects. I ran into an issue recently where I had a context declared in a using statement in a user control. The method the statement was in returned an entity object which got used in another control. So I had to detach the entity then attach it to the new context in the other control. I would like to avoid this if possible. What I'm thinking is I would like to declare a context in the master page and then pass that to any page/usercontrol that needs it so they are all using the same context and I don't have to write all these using statements.
My questions are these:
1) is it a bad practice to declare a context on Pre_Init/Page_Load and then dispose of it on Page_Unload?
2) if it is what is the best practice for handling them?
3) if I do go the route of declaring the context in the master page what is the best way to pass that to the pages/usercontrols?
My Question is can we extend one context to another in Entity Framework 4. Following is the problem background.
I am using EF4 for developing a Web-Application. My Web Application has 3 projects.
One project is for storing candidate CV information.
Another project is for storing customer information.
Final project is called CORE. this CORE contains a edmx file that should be extended by CV and CRM.
As an example email address table can be shared by both customer (CRM) and CV. To share one table with another, we should be able to extend one context (CV context) with other context (customer context). Could some one having experience using Entity Framework share your experience with me to find whether this is possible.
We have 3 edmx files in three class libraries:
Person class library(Core) with core.edmx-Basic details related to a person(name, email) CV Class library with CV.edmx wich have CV related data(Experiance,skills) Customer Relationship management system(CRM) which have customer data(sales data...)
Then we want to use core class library edmx file(Core.edmx) with cv.edmx (basically cv tables should be able to use tables from core tables) . Same way we want to use the core.edmx with CRM.edmx for the 3 rd project
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 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 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?
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;
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.
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
I am using an Entity Data Model (.edmx) in my project. I am using context.Customers to bind the grid.
Now when the datasource is binded to grid, i made some updates for 2 rows in the database.
Now, how can i capture those 2 updated rows in the context........?
I have an asp.net page (C# codebehind), and in page_load there are various linq queries returning anonymous types, such as:
var customersAdded = from r in AddedRecords
select new { Ref = r.CustomerRef, Name = r.Customer_Name };
On the page I have a button called 'export to excel', and in that buttonClick event I try to refer to customersAdded. It says it doesn't exist in the context. I know I've overcome similar issues in the past using things along the lines of:
if (File.Exists(System.Web.HttpContext.Current.Server.MapPath("~/App_Variants/" + GetUserTheme().ToString() + "/images/" + i.ImageUrl)))
So question is, how to refer to the variable? And for reference, if I say wanted to refer to a value in a control (eg a textbox on the page) would the same or different approach apply?
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 Repliessolve 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 :(
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 RepliesI have 3 tables in the database, with a Many to Many relationship:
Assessment(assessID, userID, A, B, C)Grade(gradeID, scoreA, scoreB, scoreC)AssessmentGrade(assessID, gradeID) [PK and FK]I can already Insert into the Assessment AND Grade tables without any problems.I cannot seem to figure out how to Insert into the AssessmentGrade table. There is no separate Entity, because there is only the PK/FK in the AssessmentGrade. I have looked at some tutorials, but none of them seem to address my situation.
I m making an application in asp.net 3.5. I have added .edmx file in my appliaction and create all the instances of datatable in the edmx file. now i want to know how to start querying with this edm like inserting updating and selecting etc. from database.
View 7 Replies