Can someone provide an example of how I would use the DataService with MVVMLight v4 to bind to a 'Company' Entity from my EDMX file (SQL 2008) when live or to a 'Company' collection at design time?
I have searched all over and find very few examples of how to use the DataService construct.
Sorry no idea,i use to bind Entity by making a Data Table Object(class) of the table and use Mapper to bind it:(
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Hi i write because i have configured the Audit for one single table for all my entities and its working fine for the general tables in my model, but with the Many-To-Many tables i don't know how can i do for setup the "AssociationEntryRecord"? the event is fired by EF when i do one change in this tables but i don't know how saved!
Could you please help me with this questions, thanks in advance for your help & the library...
For configuring the Entity Framework event provider use the fluent API provided by Audit.EntityFramework.Configuration.Setup()
You can include the associations as follows:
Audit.EntityFramework.Configuration.Setup()
.ForAnyContext(config => config
.IncludeIndependantAssociations());
And about your sample code (what you should have included as textual code and not as an image):
The first line is not needed, since the UseEntityFramework() will
override the DataProvider
The primary key value can be calculated as: entity.TablePk = entry.PrimaryKey.FirstOrDefault().Value.ToString();
I'm trying to bind a xtraReport-EFdatasource to a list, i have done this in designer mode quickly using the wizard, but i cant bind its datasource at runtime.
DataSource = Services.CoursesList();
I tryed this code in the report constructor, also in the XtraReport1_DataSourceDemanded event with no luck. the devexpress website show an example using bindingsource, but im using EFdatasource. Can you help me with a code sample please?
I suggest you refer this - How to use Entity Framework with Xtrareports
The best way to accomplish your task is to place your Report class and
Entity objects into a separate class library. In this case, you will
be able to bind the Report to a custom object at design time and
provide data at run time.
To pass data to your Report instance, handle the
XtraReport.DataSourceDemanded event, create your Entity objects,
and pass them to the XtraReport.DataSource property.
More References:
How to use the XtraReport with the Entity Framework
Mates, I want to update a role description using my application
I don´t know what is the better way to connect to the database and run a UPDATE statement.
Would it be Entity Framework? LINQ? None of this 2 options..
Please, suggestions.
I would say that Entity Framework would be currently the best solution for you. Not only it is strongly supported by Microsoft (well Silverlight was as well) but:
If you start with it, you can use designer. It's graphical UI will guide you when generating the model (based on database) or generating the database schema when starting with model.
Read some tutorials abut it:
http://msdn.microsoft.com/en-us/data/ee712907
And later take a look how to use some more profesionla techniques as Repository pattern or unit of work
http://www.asp.net/mvc/tutorials/getting-started-with-ef-using-mvc/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application
Not Linq ..well yes linq, but linq is the querying framework where as entity framework is the object relational mapper. So Both actually. You could do this in various other ways but those two technologies work very well together from my experience.
In Visual studio you would create a new ADO.NET project template which you then hook up to your database. and then you can update the tables and do a whole bunch of stuff. Linq is build into .NET so technically you can query any objects using linq ( which makes it so much fun ) and because your entity is an object you just reference it ( first declare it ) and then play with it
FooModel foo = new FooModel(); // Entity
var fooQuery = from _ in foo.DescriptionTable // Linq query
where _.Description == SelectedDesc // table selection query
select _;
foo.Add(fooQuery); // add to database
foo.SaveChanges(); // save changes
Something like that. There is a bit more to it that would project specific but you would have to give more details.
It is most certainly worth learning both technologies and have doubt you will find them very useful. Both can get very complex but for what you need it for you just need the basics down and then you can explore from there.
I am following the database approach first; I have created the tables in my SQL Server 2008 database, then I map those tables to Entity Framework classes using an ADO.NET Entity Data Model. But when I opened the designer.cs file I found the following code in the class definition which was created automatically:
public partial class PortalEntities : ObjectContext
so I have the following three question that get my confused:
Why does my PortalEntities class derive from ObjectContext and not DbContext as I was expecting?
Is there a major difference between ObjectContext & DbContext, or they are mainly the same and offer that same capabilities
When I try to write the something similar to the following code:
Student student = db.Students.Find(id);
I found that I cannot use .Find() method as I used to do using DbContext, so does this mean that ObjectContext & DbContext have different methods that I can use?
BR
The DbContext is a wrapper around the ObjectContext which simplifies the interface for the things we do most.
If you have an DbContext you can still access the ObjectContexttrough ((IObjectContextAdapter)dbContext).ObjectContext;
If you want to use the DbContext instead of the ObjectContext when using database first, you can switch the template that's used for generating your code. You can do this by right-clicking in your EDMX and selecting 'Add Code Generation Item'. You can then select the DbContext template.
Here is an example of the whole process.
Since VS2012 the default code generation changed from ObjectContext to DbContext.
I have created a Entity named MediaItem which is Abstract and Game inherits form it. I create the database automatically and I get a table MediaItems and MediaItems_Game.
The issue is when I do the following in my ASP.Net Controller:
private Models.DBContainer dataModel = new DBContainer();
dataModel. ---> Intellisense shows me MediaItem but I can find no way to either navigate to or use MediaItems_Game, how can I solve this? i.e. How can I grab a list of 'Games' with some 'WHERE' constraints on another table (not pictured).
Any info is appreciated, thanks.
This is how inheritance in EF works. You have only single set of parent type. If you want to get just games you will use OfType method:
var games = dataModel.MediaItems.OfType<Game>().ToList();