linq-to-entities

How to implement paging for datagrid using LINQ to Entities in wpf?

I'm new in wpf. My main problem is to understand how DataGrid works with its datacontext. It would help me a lot because I don't know how to make a universal paging usercontrol for all my datagrids in the projects for different database tables. DataGrid converts received DataContext from object to some kind of list. How it is implemented...

Entity Framework query not returning correctly enumerated results.

I have this really strange problem where my entity framework query isn't enumerating correctly. The SQL Server table I'm using has a table with a Sku field, and the column is "distinct". It isn't a key, but it doesn't contain any duplicate values. Using actual SQL with where, distinct and group by cluases I have confirmed this. Howev...

The specified type member 'EntityKey' is not supported in LINQ to Entities

I have 2 Entities "UserProfile" and "Agent", they are 1-many relationship. I want to do a query to get a list of Agents by giving the userProfileEntityKey. When I run it, I got this "The specified type member 'EntityKey' is not supported in LINQ to Entities" error. public IQueryable<Agent> GetAgentListByUserProfile(EntityKey userProfil...

Linq to Entities strange deploying behavior.

Hi I started building apps with this technology and I am facing a weird problem... on some machines I need to add theese lines to the app.config to get to work: <system.data> <DbProviderFactories> <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MyS...

Linq To Entities

This has probably been answer already but I am trying to return the primary key after inserting a record to the database. Does anyone know how this is accomplish after the record has been created? ...

LINQ Guid toString()

Hi this seems like it should work, from something in collectionofsomestuff select new SelectListItem(){Text = something.Name, Value = something.SomeGuid.ToString(), Selected = false}; When I try to do this it doesn't work give me error LINQ to Entities does not recognize the method 'System.String ToString()' method, and thi...

How to create a Linq To Entities expression

HI, I'm using Linq To Entities and I'd like to convert this return db.Products .Where(p => p.idUser.Equals(id) && p.Category.Genre.Any(g => g.visible)) into something like Func<Genre, bool> expr = g => g.visible return db.Products .Where(p => p.idUser.Equals(id) && p.Cate...

How can I use external expressions in Linq with EF4 (and LINQKit)?

I want to separate out often used expressions in linq queries. I'm using Entity Framework 4 and also LINQKit but I still don't know how I should do it the right way. Let me give you an example: Article article = dataContainer.Articles.FirstOrDefault(a => a.Id == id); IEnumerable<Comment> comments = (from c in article.Comments wher...

How to update single object in sql to linq

For example a = datacontext.customers.FirstOrDefaul(); b = datacontext.customers.Skip(1).FirstOrDefaul(); a.name="name1"; b.Name="name2"; When i call datacontext.SubmitChanges(), Two object updated. I don't want this. I need only Update a object. How do it? EDIT WPFWindow windowA=new WPFWINDOW() windowA.DataContext=a; windowA.Sh...

DynamicQuery: How to select a column with linq query that takes parameters

Hello, We want to set up a directory of all the organizations working with us. They are incredibly diverse (government, embassy, private companies, and organizations depending on them ). So, I've resolved to create 2 tables. Table 1 will treat all the organizations equally, i.e. it'll collect all the basic information (name, address, ph...

linq sort many 2 many question

My main entity is called [Contract]. Contract has a many 2 many relationship w/ [Service]. When I query for a list of Contracts I grab the 1st Service available like this: IQueryable<Contract> q = ctx.Contracts.Skip(startRow - 1).Take(pgSize); q.Select(c => new ContractSearchResult() { ContractID = c.Contra...

How to build a dynamic linq query

Hello Everyone, I am trying to find the best way to build a dynamic linq query and populate a list. The user will have about five different fields in which they can choose to filter on. Currently i have the following code: List<TBLPROMOTION> promotionInfo = null; bool active = true; int storeId = 1 using (WSE ...

How to implement a left outer join in the Entity Framework.

I have the following SQL query:- select distinct * from dbo.Profiles profiles left join ProfileSettings pSet on pSet.ProfileKey = profiles.ProfileKey left join PlatformIdentities pId on pId.ProfileKey = profiles.Profilekey I need to convert it to a LinqToEntities expression. I have tried the following:- from profiles in _dbContext....

Linq Paging - How to incorporate total record count

Hello everyone, I am trying to figure out the best way of getting the record count will incorporating paging. I need this value to figure out the total page count given a page size and a few other variables. This is what i have so far which takes in the starting row and the page size using the skip and take statements. promotionInfo = ...

LINQ to Entities Issue

using(SampleEntities entities = new SampleEntities()) { var userMap = from ad in entities.SampleGroupsSet from uid in distinctUserIDs where ad.ShortUserID.ToLower() == uid.ToLower() select new {shortID = uid, longID = ad.UserID}; string userID = "sampleId"; var longIDs = from map in userMap ...

Linq - How to query specific columns and return a lists

Hello Everyone, I am trying to write a linq query that will only return certain columns from my entity object into a list object. Below is my code which produces an error(can't implicitly convert a generic list of anonymous types to a generic list of type TBLPROMOTION): IQueryable<TBLPROMOTION> matches = webStoreContext.TBLPROMOTION....

Linq to Entities DateTime Conversion

If given a an entity with a datetime as a string... what are my options to filter the data with Linq to Entities on the date? It does not seem to support me doing datetime conversions. Basically, I want to accomplish: var filtered = from item in entities.itemsSet where Convert.ToDateTime(shift.starttime) >...

Converting a Linq expression tree that relies on SqlMethods.Like() for use with the Entity Framework

I recently switched from using Linq to Sql to the Entity Framework. One of the things that I've been really struggling with is getting a general purpose IQueryable extension method that was built for Linq to Sql to work with the Entity Framework. This extension method has a dependency on the Like() method of SqlMethods, which is Linq to...

Walking a hierarchy table with Linq

I have a table with two columns, GroupId and ParentId (both are GUIDS). The table forms a hierarchy so I can look for a value in the “GroupId” filed, when I have found it I can look at its ParentId. This ParentId will also appear in the GroupId of a different record. I can use this to walk up the hierarchy tree from any point to the root...

Linq Grouping by 2 keys as a one

Hello! I write a simple OLAP viewer for my web-site. Here are the classes (abstract example): Employee { ID; Name; Roles[]; //What Employee can do } Order { Price; Employee Manager; Employee Executive; //Maybe wrong english. The person which perform order } Employee can be Manager and Executiv...