entity-framework

问题 The design of EF forces developers to inherit the DbContext class. Some reusable libraries (such as ASP.NET Identity) typically provides its functionality using the same inheritance route, i.e. by providing the IdentityDbContext base-class. But obviously this won't work if you have 2 such libraries, e.g. requiring you to inherit from IdentityDbContext and CmsDbContext at the same time, which is obviously impossible to do on .NET. The result that I want is to have an application-dbcontext that

问题 I have a list I am populating with total sales from a team. lstTeamSales.OrderBy(x => x.TotalSales); This list has an int userID and a decimal totalSales . I order it by totalSales . How can I at that point figure out the rank for the person logged in? I know I can compare the person who is logged in by his userID to that of the userID in the list. If he is #3 in sales I need to return an int of his rank which would be Rank 3. 回答1: The question can be rephrased to "How do I get index of

问题 I have a EF code first context which represents a queue of jobs which a processing application can retrieve and run. These processing applications can be running on different machines but pointing at the same database. The context provides a method that returns a QueueItem if there is any work to do, or null, called CollectQueueItem . To ensure no two applications can pick up the same job, the collection takes place in a transaction with an ISOLATION LEVEL of REPEATABLE READ . This means that

问题 I want Linq to group by date but display in text here is my code var groups = _uow.Orders.GetAll() .Where(x => x.Created > baselineDate) .GroupBy(x => x.Created.ToString("yyyy-MM-dd")); var orders = new { Day = groups.Select(g => g.Key).ToArray(), Total = groups.Select(g => g.Sum(t => t.Total)).ToArray(), }; the result is (not good to put in label of graph) {"Day": [2, 3, 4, 5], "Total": [9999.00, 9999.00, 9999.00, 9999.00] } But i want this (Monthly) "Day": ['Jan', Feb', 'Mar', 'Apr'],

问题 When going through a learning article about related entity loading in Entity Framework MSDN, I came across the following: It is also possible to eagerly load multiple levels of related entities . The queries below show examples of how to do this for both collection and reference navigation properties. ...[Examples demonstrating the above]... Note that it is not currently possible to filter which related entities are loaded . Include will always being in all related entities. This seems

问题 When going through a learning article about related entity loading in Entity Framework MSDN, I came across the following: It is also possible to eagerly load multiple levels of related entities . The queries below show examples of how to do this for both collection and reference navigation properties. ...[Examples demonstrating the above]... Note that it is not currently possible to filter which related entities are loaded . Include will always being in all related entities. This seems

问题 In continuation with the question asked here, even with EF 6, I am having issues generating the [Required] Data Annotation for certain fields for a model autogenerated from Database Table. Am I missing something or is it still not supported? The DB fields that I am looking at are "NOT NULL". Any help will be appreciated! I have too many tables and fields to look at and automating this process via Entity framework will be nice to have! 来源： https://stackoverflow.com/questions/29827993/required

问题 Hello I am writing an ASP.Net MVC application and I have a special class dedicated for Database connection. In my HomeController I call the static methods of this special DB class, which return the needed data into objects. I use the Entity Framework in order to achieve this. However I get a strange exception when I try to use the List from my Controller. I believe that the problem is that I have a virtual inner collection that is disposed after the entity framework methods are done. I can

问题 Modifying an answer from this question slightly, suppose I run this code: public int SaveOrUpdate(MyEntity entity) { var sql = @"MERGE INTO MyEntity USING ( SELECT @id as Id @myField AS MyField ) AS entity ON MyEntity.Id = entity.Id WHEN MATCHED THEN UPDATE SET Id = @id MyField = @myField WHEN NOT MATCHED THEN INSERT (Id, MyField) VALUES (@Id, @myField);" object[] parameters = { new SqlParameter("@id", entity.Id), new SqlParameter("@myField", entity.myField) }; return context.Database

问题 Modifying an answer from this question slightly, suppose I run this code: public int SaveOrUpdate(MyEntity entity) { var sql = @"MERGE INTO MyEntity USING ( SELECT @id as Id @myField AS MyField ) AS entity ON MyEntity.Id = entity.Id WHEN MATCHED THEN UPDATE SET Id = @id MyField = @myField WHEN NOT MATCHED THEN INSERT (Id, MyField) VALUES (@Id, @myField);" object[] parameters = { new SqlParameter("@id", entity.Id), new SqlParameter("@myField", entity.myField) }; return context.Database