LINQ to Entities Where clause with custom method

How to unit test async methods of Entity Framework with a multiple clauses

Finally found the answer ...here....IQueryable needed to be added like so:...public class TestDbAsyncEnumerable<T> : EnumerableQuery<T>, IDbAsyncEnumerable<T>, IQueryable

error: LINQ to Entities does not recognize the method DataLength

It turns out that the answer is that I'm using the wrong function....instead of...System.Data.Objects.SqlClient.SqlFunctions.DataLength ...I should be using...System.Data.Entity.SqlServer.SqlFunctions.DataLength ...located within EntityFramework.SqlServer.dll

How can I make Linq extension method available for the entities?

I wrote a method that extends ...System.Linq... class. My ...ContainsAnyWord... method allows me to search all words in a string against a string instead of comparing one string to another....Here is the method that I wrote to extend ...Linq...public static class LinqExtension { public static bool ContainsAnyWord(this string value, string sear...

Entity framework core Output parameter not working in store procedure using FromSql method (Linq)

I don't' have access to your whole code, but nothing ever gets executed against your queryable source until you try to enumerate it. So, probably it didn't run the Stored Procedure when you tried to get the OUTPUT....To force immediate query evaluation you can do it:... IQueryable<T> foo = _context.Set<T>().FromSql("Sp_Todo @totalItems OUTPUT", new...

EF Core: Add custom LINQ in Up method of Migration class

I found solution....In ...Startup... class I defined static variable:...public static Func<MyContext> ContextFactory; ...In constructor of ...Startup... class I assigned variable:...public Startup(IHostingEnvironment env, IConfiguration config) { MyContext GetContext(IConfiguration configuration, IHostingEnvironment environment) { v...

Entity Framework Core: Custom Linq methods for querying view models from DbContext

You should take a look at a mapping framework to map the DB Entities to the ViewModels. For example, we are using ...Automapper... to achieve this....This allows you to define the mappings centrally and reuse them. This should simplify most of the code, because the logic you want to refactor is in the ...select... part of the query....MappingConfig...

Entity Framework Core LINQ query with multiple where clauses

Assuming ..._sourceDAL.Donneesource... gives you an ...IQueryable<T>... then you should be building up your query by adding ...Where... clauses inside an ...if... statement. This is because an ...IQueryable... will not run a query against the database until you materialise it, i.e. with a ...foreach... or a ....ToList().... So something like this:....

Make Entity Framework (using Linq queries) use alias of custom field instead of redoing the subquery

Is there a way to force Entity Framwork to use the alias of a subquery instead of doubling it for an OrderBy?...var results = Users.Select( u => new { u.idUser, u.Name, nbChilds = u.Children.Count }) .OrderBy( u => u.nbChilds ); ...This will be converted in SQL to :...SELECT [u].[idUser] AS [idUser], [u].[name] AS [Name], ( ...

Extending EF Core 'where' clause with custom expression

You need to change the ...Func<T, DateTime>... arguments to ...Expression<Func<T, DateTime>>... and incorporate them in the desired expression....Unfortunately neither C# compiler nor BCL helps with the later task (expression composition from other expressions). There are some 3rd party packages like ...LinqKit..., ...NeinLinq... etc. which address...

Return a parent entity together with its child entities using LINQ method syntax

Use ...Eager loading...[HttpGet("{id}")] public async Task<ActionResult<KeyField>> GetKeyField(int id) { var keyField = await _context.Set<KeyField>() .Where(x => x.KeyFieldId == id) .Include(x => x.ReferenceFields) .FirstOrDefaultAsync(); if (keyField == null) { ...