I use the Entity Framework and Linq to Entities with MVC 2.0. When use the DropDownListFor from Html helpers to populate a dropdown that contains an ID from a foreign object, I post the form data but I canīt set the correct relation. Using the debug, I can see the ID retrieved from dropdown at my returned foreign object ID, but I think that I not use the association correctly.
View 4 Replies
I don't know how to retrieve a DropDownListFor value on form post and how to validate it.
This is my scenario:
HTML markup:
[Code]....
Model:
[Code]....
I'm not able to validate this dorpdown and when I test if the Model is valid I have to re-fill the Location property
[Code]....
otherwise I get an "object reference not set" error on post-back.
How to use Stored Procedures with Linq to Entities? I prefer an example with input and output The videos on asp.net only show how to do this with Linq to SQL.
View 5 RepliesI have a simple join:
SELECT * FROM MessageAlerts AS A LEFT OUTER JOIN Contacts AS C ON A.ContactId = C.Id LEFT OUTER JOIN
Users AS U ON A.UserId = U.Id INNER JOIN Businesses AS B ON B.Id = C.BusinessId OR B.UserId = U.Id
how to do this : ON B.Id = C.BusinessId OR B.UserId = U.Id with linq in entity framework.
WHY are all the examples on this site linq to SQL? Did ms not themselves announce dropping support for l2SQL over a year ago? i really don't get it. Examples are great.. but really not helping me since i've gone ahead and listened to MS. And can someone at MS clarify what the position is for linq 2 SQL.. Is it supported? Recommended? What the hell.
View 7 RepliesI am trying to learn LINQ to entities, and am working out how to best structure my BLL layer. I have generated the entity model and have created a generic repository in my DAL that returns results as IList<T>. I initially created the BLL to also return
results as IList<T>:
public IList<DAL.Customer> SelectAll()
{ [code]...
Now I am working on the aspx page, and I can create an ObjectDataSource and configure it to use my BLL, but since I am returning IList, I can't sort since I am not using a DataView. I have seen some articles on the web for converting IList to DataView, but that seems like a lot of overhead for every query.My goal is to keep a clean separation between layers without making things overly complicated. I would like to know how others have done this, or maybe a link to a good tutorial that shows how to structure all three layers.
I am building a web application in asp.Net 4.0 and entity framework. I am trying to retrieve a list of products based on a collection of id's. I first gather all the id's in a collection and then pass it to the linq query. I am trying to get a functionality similar to the IN clause in SQL. The problem seems to be with the Contains() method in the Linq to entities query. Here is my Linq code:
[Code]....
I got the above Linq to entities method from here: [URL]
I have a message table that self joins to itself where Message.ID == Message.Parent. So I have 1 Message with several ChildMessages. This is set up nicely with a Navigation property.
The code is currently:
var message = from m in soe.Messages.Include("ChildMessages")
where m.ID == id
&& m.IsActive
select m;
return message.FirstOrDefault();
What I really want is to only return 1 Message (that is equal to a particular ID and isActive) with all of its Active ChildMessages and I want to do it in one call to the database.
I have a table of user ids that is huge.
I have an array of user ids that I want.
I have two tables that have a foreign user id key.
What is the best way to get this information performance wise?
Ideally in SQL the final result would be somewhat like this (null values if there is no user ID in one table but not the other):
userid table1value table2value
1 null 12
5 123 null
i have a table with a field name called 'Firstname' and another field name called 'Lastname'. I would want to have a single column in my GridView which show Fullname and then the firstname and lastname are showed here under an alias. Also, i am binding my GridView using LINQ.So is there a way to create aliaswith LINQ and to use these with GridView ? Would love to have an hint about how i can realize this task.
View 5 RepliesIn linqtosql you could do something like:
datacontext.CreateDatabase() to generate a database from the model in sql.
I'm wanting to do the same thing in linq to entities.
Say I have a class MyEntities which inherits from ObjectContect is there a similiar method?
have already used the latest technology in a professional manner. NETBasically I have two tables related 1 to 1:the Users table and the table ProfiloPersonale is the key to the Users table that this table are ProfiloPersonale iduser and type uniqueidentifier and diagram sql server 2008 I can clearly see the report, I also did a test to insert a record in the users table ( fictional) directly from sql server and everything works.With LINQ to Entities does not work:The entities 'LEntities.Users' part of the eport 'ProfiloPersonale'.Found 'ProfiloPersonale' related to 0.Expected 1 'ProfiloPersonale'Of course what I am doing is to first create the user and then create their profile in the db, taking the id of the registered
View 1 RepliesI have a view on my database and I am trying to add a new record using the AddTo method but it is not working. I noticed that LinqToEntities is creating the insert statement like this
Insert into (select field1, field2 from my_view) (field1, field2) values (value1, value2)
Is it possible to make LinqToEntities create the insert statement like the one below ?
Insert into my_view (field1, field2) values (value1, value2)
I am trying to update an item with entity framework but I am unable to do that;
[Code]....
it didn't give any error. it passed but when I looked at the database, nothing changed. can you provide me the right way.
All I am trying to do is query the database, then get the returned values, so that I can do some calculations. But, I don't understand how to get the values from the database row that is returned, so that I can assign it for usage.
I would like to do something where the logic goes: for the index of [1] (which is just column 1), multiply it by 2. For the index of [2] (which is just column 2), multiply it by 3.
Example below:
This does NOT work:
[Code]....
In the code bdehind && syntax does not work, any ideas?
Entities ctx3 = new Entities();
var uniqueQuote = from quot in ctx3.Quotes.Include("aspnet_Users").Include("Enquiries")
where quot.Enquiries.EnquiryId == selectedEnquiryId && [code]...
Error 2 Delegate 'System.Func' does not take '1' arguments C:LocalGarageFinderLocalGarageFinderEnquiryDetail.aspx.cs 56 33 LocalGarageFinder
Iīve been trying to add jquery autocomplete in my website, iīm using asp.net 4 and linq to entities ....
Iīve searched a lot but couldnīt find an answer for this especific case.
I want to compare Dates in my Linq To Entities, and here is my code
var query = from ann in _announcementEntities.Announcements
where ann.CreateDate.Date == dateTime.Date
select ann;
thou this block of code throws an error:The specified type member 'Date' is not supported in LINQ to Entities
how can I make this work?
I am use the new ASP.NET MVC 2 and Entity Framework, but when I try to create a new view with strongly-typed option selected, the entity objects is not appears at dropdown and I cannot use the view creation wizard. I recompile the solution, but still not appears yet. Have any workaround that I forgot to do to enable the entities to be displayed at dropdownlist ?
View 5 RepliesI am working on a website similar to nerddinner. Is it possible to perform similar join
using Linq to entities what is done with linq to sql in nerddinner.I am posting the codes below.
public IQueryable<Dinner> FindByLocation(float latitude, float longitude) {
var dinners = from dinner in FindUpcomingDinners()
join i in db.NearestDinners(latitude, longitude)
[code]...
What do i need to do in order to be able to query across multiple databases which are in the same db engine?
I have added the .edmx file of 1 database, but i only need 1 view from another db.
I have a solution which uses Linq to SQL Data Classes to acced the db. I have a project for my domain objects in my solution, which is a class library and has the dbml file. When I set up the dmbl using the wizard, Visual Studio created anapp.config file on that project with the connection string. It also creatting asettings file with the same info. I've noticed that if I change the connection string in the settings file, the app.config gets updated, which is the expected behaviour.
However, I'm having a problem when I deploy my web site to the production server. I already set the app.config file's Build Action to "Content", and also set Copy to ouput directory to "Always". Nevertheless, when I install the web site and change the connection string in the app.config file, it still takes the old connection string, so obviously I get an error. I've found that it only works if I change it with in Visual Studio and then compile, but of course that's not an optimal solution, because any change in the production db server would mean I have to change my project's assembly, thus generating a new version.
What do I have to configure so that the assembly takes the connection string form my app.config file directly after I deploy?
I have the following LINQ query that does a left join:
var results = from v in ctx.dat_Visitor
join sp in ctx.vwSP on v.lu_Mentor.ID equals sp.ID into sp2
select new {
[code]...
My problem is that this LINQ query times out on me. I even upped the default timeout from 15 seconds to 120 seconds and it still times out. dat_Visitor has no more than 10 records in it, but vwSP (which is a view) has somewhere around 100,000 records. I know for sure that the timeout has to do with when I attempt to actually return sp2 in the results. If I change my LINQ query to not return sp2 in the results, then it is quick. Without sp2 the query looks like such:
var results = from v in ctx.dat_Visitor
join sp in ctx.vwSP on v.lu_Mentor.ID equals sp.ID into sp2
select new {
Visitor = v.Name,
Tot = sp2.Count()
};
Lastly, I'm using the 3.5 framework, but I am having serious thoughts about upgrading the website to 4.0, since I could then use DefaultIfEmpty().
What is the best way to create a custom results page using Linq to Entities?
Do I pass the values to the result page, and do the query on the result page?
or
Do I pass the query results to the custom results page?
What is the best way to pass this?
Is there an example of this on the internet?
Now I know there is a reason to this odering but my tiny little brain can't get my head around it.I am using a webservice to pull through data to a webp[age and have the following that is so far pulling data through from UUF1:
public string[] GetBuyer(string Memberkey)
{
try
[code]...
