I use EF 4 and C #.
I need populate a Pure Junction Table (containing only FK to other tables) when an EntityDataSource _Inserted event is raised.
I have 3 Tables in my Database:
[code]....
Here a useful resource:
But I am not able to implment it:
[code]....
I have a question, much liket this unanswered one. I'm trying to work with the entity framework, and having a tough time getting my foreign tables to update. I have something basically like this in the DB:
Incident (table):
-ID
-other fields
Responses (table):
-FK:Incident.ID
-other fields
And and entities that match:
Incident (entity)
-ID
-Other fields
-Responses (EntityCollection of Responses via navigation property)
Each Incident can have 0 or more responses.
In my Webpage, I have a form to allow the user to enter all the details of an Incident, including a list of responses. I can add everything to the database when a new Incident is created, however I'm having difficulty with editing the Incident.
When the page loads for edit, I populate the form and then store the responses in the viewstate. When the user changes the list of responses (adds one, deletes one or edits one). I store this back into the viewstate. Then when the user clicks the save button, I'd like to save the changes to the Incident and the Responses back to the DB. I cannot figure out how to get the responses from the detached viewstate into the Incident object so that they can be updated together.
Currently when the user clicks save, I'm getting the Incident to edit from the db, making changes to the Incident's fields and then saving it back to the DB. However I can't figure out how to have the detached list of responses from the viewstate attach to the Incident. I have tried the following without success:
Clearning the Incident.Responses collection and adding the ones from the viewstate back in:
Incident.Responses.Clear()
for each objResponse in Viewstate("Responses")
Incident.Responses.add(objResponse)
next
Creating an EntityCollection from my list and then assiging that to the Incident.Responses
Incident.Responses = EntityCollectionFromViewstateList
Iterating through the responses in Incident.Response and assigning the corresponding object from viewstate:
for each ObjResponse in Incident.Responses
objResponse = objCorrespondingModifedResonseFromViewState
Next
These all fail, I'd like to be able to merge the changes into the Inicdent object so that when the BLL calls SaveChanges on the changes to both the Incident and Responses will happen at the same time.
In an MVC view, I'm looking for a way to determine if a parent entity's collection of child entities is empty, so I can decide if I need to call a RenderPartial() or not.
For a one-to-one I've been using the following:
<% if (Model.Book.GenreReference.EntityKey != null) %>
{.....}
but I'm unsure how to do it in a one-to-many scenario, or if it can even be done without the use of Include() or Load().
I've been learning MVC 2 and I have pretty much everything understood except for the model part of things, I understand what the model is but actually implementing it has me confused.
Here's my situation, I have my DB which has 3 tables;
Ideas - table of ideas
Tags - table of tags
IdeaTag - link table connecting the above 2 tables via FKs
So when using the Entity Framework (.edmx) designer in VS2010 I get 2 classes created in the Designer, which obviously map to my DB tables and Navigation Properties in Idea for Tags & Idea for Tag.
So this is all fine until I actually try to add tags to an idea, what's the best practise for dealing with Navigation Properties? I wanted to add a Textbox which will then map to the Tags property in the Idea class but I'm unsure how I'd go about this.
Most of the MVC tutorials which discuss EF or Linq to SQL are quite basic.
I have two Entity classes: Order and OrderItem. Order contains a navigation property OrderItemSet of type
System.Data.Objects.DataClasses.EntityCollection<OrderItem>
On an aspx page is a FormView bound to this EntityDataSource:
[code]....
When I run the application I get an exception pointing to the line DataSource='<%# Eval("OrderItemSet")%>' in markup and telling me:
DataBinding: System.Web.UI.WebControls.EntityDataSourceWrapper does not contain a property with name 'OrderItemSet'
What is wrong here?
I am using the Entity Framework for the first time and want to know if the following is possible - I have generated my classes from the DB, and have one called Category.
Obviously it has all my fields in the table (ID, CategoryName, SortOrder etc..) but I want to know if I can add a custom property which is not in the table, but is actually the result of a custom method.
I want to add a new property called 'CategoryURL' which is basically the 'CategoryName' property run through a custom method and returns a hyphenated string.
My initial thought is inheriting from the generated Category class and creating something like this inside?
public string CategoryURL
{
get{ return MyCustomMethod(this.CategoryName) }
}
Is this the correct approach? And will 'this.CategoryName' work as I think it should? Basically the end result is when I return a list of 'Category' I want this to be part of the class so I can use it in my foreach loop.
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
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I have a stupid problem with the Entity Framework. I get the following Exception:
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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 get a list of objects from the Entity Framework data context.
var list = context.EntityA;
the EntityA is the main object (contains the primary key), but has a navigation property called "EntityALanguages", which contains language specific properties.
now i want to bind the list to a dropdownlist and need so set DataValueField and DataTextField properties from the dropdownlist.
how can i set the DataTextField to a property of a navigation property, something like:
this.ddl.DataValueField = "GUID";
this.ddl.DataTextField = "EntityALanguages.ShortDescription";
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
Is there a way to get ADO.NET Entity to generate 1:1 navigation properties? If I do foreign keys I always get 1:N navigation properties.
View 2 RepliesI'm developing ASP.NET 4.0 Website using SQL server 2008 with Membership Framework. It runs fine so far with static navigation in my master page which uses static Web.SiteMap file to generate the Navigational Menu. I am wondering If there is any way to generate this file dynamically depending on the user's role or Identity.
I would also like to know If there is any way to store this setting in database using membership framework so that I dont have to present each and every links to all users or roles who is not authorized to see some of pages in website or any other way to generate menu at runtime.
I'm using EntityDataSource to retrieve my items, and i want to get the items for a particular region. (items and regions has a many to many relationship, thus item has a regions navigation property). and I'm using "IN" to filter the items. tried several combinations and it kept on throwing various errors. how can i get this sorted out:
Below is My DataSource:
[code]....
I have an asp.net repeater control with a series of asp:hyperlink's
<asp:HyperLink runat="server" ID="name" NavigationUrl="~/Pages/display.aspx?fileid={0}&user={1}" />
and then on the OnItemDataBound method:
fullname.NavigationUrl=string.Format(name.NavigationUrl, user.fileid, user.userid);
So that gives me a series of URLs in the repeater:
[URL]
OK, so with a simple proxy tool someone can replace either of the parameters with some OTHER number to get access to what they shouldn't see.
server-side validation and authentication aside, is there a better method other than passing parameters when trying to create a dynamic URL within a repeater?
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 Replies