Retrieving Data Is Slow Only When Use Entity Framework In The Code Page?
Aug 20, 2010
When I use classical ADO.NET or (which is interesting) EntityDataSource (e.g. for GridView), then page load within 1 second.But when I use ic codefile code like:
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Cty = CType(Request.QueryString("cty"), Integer) ' course type
Page.SetFocus(ddl_FGPhotosOK)
If Not IsPostBack Then ' read course status
Using ctx_sdbEntities As New sdbEntities()
[code]...
View 2 Replies
Similar Messages:
Feb 9, 2011
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>();
}................................
View 9 Replies
Oct 25, 2010
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.
View 1 Replies
Oct 13, 2010
We have an ASP.NET MVC site that uses Entity Framework abstractions with Repository and UnitOfWork patterns. What I'm wondering is how others have implemented navigation of complex object graphs with these patterns. Let me give an example from one of our controllers:
[code]....
It's a registration process and pretty much everything hangs off the POCO class Person. In this case we're caching the person through the registration process. I've now started implementing the latter part of the registration process which requires access to data deeper in the object graph. Specifically DPA data which hangs off Legal inside Country.
The code above is just mapping out the model information into a simpler format for the ViewModel. My question is do you consider this fairly deep navigation of the graph good practice or would you abstract out the retrieval of the objects further down the graph into repositories?
View 2 Replies
Feb 14, 2011
I have a good friend who owns a print shop and he has asked me to create him a simple online shop where he can take print orders. His print shop location is kind of hidden, and business isn't going well at the moment. This is why he wants to move online. I said I would do it for him, but it will take a while before he has anything to look at. Where I am most stuck is the Model. The problem with this sorts of shops is that each Product, depending on its category would have different attributes. How ? Here is an example: [URL] A user would choose a product category, then he/she would get to the following: [URL] Now he/she would click the Order link to order a certain qunatity. On the next page, depending on what category they are in, they'll get a form where they can choose order attributes. There aren't many attribues for BUSINESS CARDS. But if they had chosen CARBONLESS FORMS, they would get options to tweak like: Squencial Numbering to start from 103490Position of Numbering..etc
I asked for advice at the SQL Server forums, and finally I came up with something like this:[URL] But with that database design, I will have a lot of type casting to do for the attributes ! << In fact I'm not sure if that would be even possible. Then I watched this video, and the author does something cool ! she uses Inheritance. Then I started Wonding ... Is it possible for me to have a Parent [ Product ] class, and have its children entities with different (added) attributes?
View 1 Replies
Jan 19, 2011
I would like to have a short example on how do you actually perform relationships in Entity Framework 4 Code-First CTP 5 ?
Would love an example for these kind of relations :
* one-to-many
* many-to-many
View 1 Replies
Feb 8, 2011
I been looking but I cant find any info on this topic Anyway I got a model that looks like this.
[Code]....
I want to cascade delete a category with all its sub categories but I cant make that reference in the database, not with the option to cascade update or delete. It work fine with pagecontents and all the other I got its just this same table reference. In NHibernate I do the cascade setting hbm or with a better way using the fluent option. How do I go about this task now?
View 1 Replies
Jan 24, 2011
ive tried to build some base project with above technologies. I wanted maximum flexibility and testability so i tried to use patterns along the way to make this as a base for future projects. However, it seem.something is wrong or whatever and i really need help here. So
i have two questions :1- Is there anything wrong with my current code ? Ive applied patterns correctly ?
2- Why do this code actually connect to the database, create it, but doesnt support insert even if i perform the corrects operation ? (Look at the end of the post for details about this error)
I have two entities : Comment and Review
COMMENT [Code]....
REVIEW[Code].... I built up a base repository for each of them this way :GENERIC REPOSITORY[Code]...For specific operations, i use an interface :[Code]....So i am getting the generics operations from the abstract class plus the specific operations :[Code]....As you figured out, i also use a database factory will produce the database context :DATABASE FACTORY [Code]....DISPOSABLE (Some extensions methods...)[Code]....DATABASE [Code]....And to finish, i have my unit of work....UNIT OF WORK[Code]....I also binded using Ninject the interfaces :NINJECT CONTROLLER FACTORY [Code]....however, when i call in the constructor ...[Code]....
This seem to create the database but doesnt't insert anything in the database in EF4. It seem that i may figured out the problem.. while looking at the database object.. the connection state is closed and server version throw an exception of this kind :
ServerVersion = '(((System.Data.Entity.DbContext (_database)).Database.Connection).ServerVersion' threw an exception of type 'System.InvalidOperationException'
I am doing the right things ? Is there anything wrong in what ive built ? Also if you have recommandation about the code i posted, i would be glad. I am just trying to the learn the right way for building any kind of application in MVC 3. I want a good a start.
I use :
- Entity Framework 4 Code-First CTP 5
- ASP.NET MVC 3
- Ninject as DI Container
View 4 Replies
Aug 5, 2010
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]....
View 1 Replies
Jan 18, 2011
Im a fan of the EF code first and with its last preview of the CTP5 I wonder if it would be safe for me to use this for a smaller site for customer? I would love to get your opinions on this? And any good sources for tutorials and information would be sweet. I'm currently reading the post on scottgu's blog about it.
View 1 Replies
Jan 4, 2011
I have two entities (Customer and CustomerRole) and would like to declare many-to-many relationship between them. I can do using the following code:
modelBuilder.Entity<CustomerRole>()
.HasMany(cr => cr.Customers)
.WithMany(c => c.CustomerRoles)
.Map(m => m.ToTable("Customer_CustomerRole_Mapping"));
But it creates the relationship (and the third mapping table) with cascade delete switched off by default. How can I tell EF to create the relationship with cascade delete switched on when using many-to-many?
View 1 Replies
Jan 3, 2011
I have the following classes:
public class Category
{
public int CategoryId { get; set; }
public string Name { get; set; }
}
public partial class CategoryMap : EntityTypeConfiguration<Category>
{
public CategoryMap()
{
this.HasKey(c => c.CategoryId);
this.Property(c => c.Name).IsRequired().HasMaxLength(400);
}
}
public class MyObjectContext : DbContext
{
public MyObjectContext(string connectionStringName)
: base(connectionStringName)
{
}
public DbSet<Category> Categories { get; set; }
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Configurations.Add(new CategoryMap());
base.OnModelCreating(modelBuilder);
}
}
Now when I run the following code I get an exception (GenericArguments[0], 'System.Int32', on 'System.Data.Entity.Internal.Linq.ReplacementDbQueryWrapper`1[TEntity]' violates the constraint of type 'TEntity')
DbDatabase.SetInitializer<MyObjectContext>(new DropCreateDatabaseIfModelChanges<MyObjectContext>());
using (var context = new MyObjectContext("NopSqlConnection"))
{
var query1 = from c in context.Categories
select c.CategoryId;
var test1 = query1.ToList(); //works fine
var query2 = from c in context.Categories
where query1.Contains(c.CategoryId)
orderby c.Name descending
select c;
var test2 = query2.ToList(); //throws the exception
}
View 1 Replies
Sep 25, 2010
i have a web-site which uses forms based authentication. thus i have a login page with a login control on it. how would i go about coding the authenticate event of this control to talk to the Entity Framework to validate the user credentials?
View 2 Replies
Nov 2, 2010
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 Replies
Jun 30, 2010
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?
View 1 Replies
Mar 22, 2011
I have a web form (Page1.aspx) in which I am passing an ID as query string to another page (Page2.aspx). Now in this page I have EntityDataSource which binds to GridView. How should I populate this gridview with that ID?
Eg. If my ID is 1056, then in my DataGridView in Page2.aspx should populate elements of this ID.
This is the code:
protected void Page_Load(object sender, EventArgs e)
{
string getEntity = Request.QueryString["EntityID"];
int getIntEntity = Int32.Parse(getEntity);
if (getIntEntity != 0)
{
//What should I do here???
}
}
View 2 Replies
Mar 12, 2010
I have an ASP.NET Page that updates registered User Address Details for a selected record.
Below is the Update method that i am calling from Controller.
When i am calling ApplyPropertyChanges method, I am getting the below error.
Did anyone run into the same error while updating the record with Entity Framework.
[code]...
View 4 Replies
Feb 10, 2011
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.
View 2 Replies
Mar 31, 2011
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.
View 1 Replies
Sep 29, 2010
I have created a table in my Oracle database and am trying to add / edit / delete/ query the records. This table already has 4000000 records. Now when I try to query the database, it takes close to 3 minuetes to return records. I have tried creating indexes, but was not successfull so far.
Following is the structure:
User : varchar(20)
Fac : varchar(10)
Prm: varchar(100)
I am using the following code in VS2005:
[Code]....
View 4 Replies
Jun 12, 2010
I have a textbox that I need to make sure the case is right. I am using the code below but it is very slow, plus when I close my web page I get an error.
[Code]....
View 4 Replies
Aug 9, 2010
I have been asking my self this question from the time i started workin in the software development field, What is the best way to access data? Which gives the best performance? Which is the best for maintainability? There are lots of solutions to deal with database in the Asp.Net web app,Entity framework 4.0 Classes generator using ADO.Net such as Code Author ( i liked the way it works and the way it accesses the database using the data access block in Microsoft Enterprise Library). i will start a new project tomorrow,and i don't know which approach is better?
View 2 Replies
Mar 1, 2011
I have the option to query and XML file or use the Entity Data framework. What datasource provider would have better performace?
View 2 Replies
Jan 25, 2011
I plan to use the ADO.NET Entity Framework for data access and have a few questions around this
1. Is there some inbuilt mechanism to handle concurrency (optimistic or pessimistic)?
2. Does the ADO.NET entity framework My SQL?
View 2 Replies
Sep 21, 2010
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 Replies
