entity-framework

问题 I need to make “EF Core 2.1.0” remove white space from Strings fields in queries, “HasConversion” not is not working, can you tell me why? entity.Property(e => e.Name) .HasConversion( new ValueConverter<string, string>(v => v.TrimEnd(), v => v.TrimEnd())); -using DB2 database and .net core 2.1 Query: public List<ItemServico> List() { return _uow._db.ItensServico.ToList(); } 回答1: That's what the varchar type is for, to trim spaces automatically, and efficiently. Manual trim() operations have

问题 I need to make “EF Core 2.1.0” remove white space from Strings fields in queries, “HasConversion” not is not working, can you tell me why? entity.Property(e => e.Name) .HasConversion( new ValueConverter<string, string>(v => v.TrimEnd(), v => v.TrimEnd())); -using DB2 database and .net core 2.1 Query: public List<ItemServico> List() { return _uow._db.ItensServico.ToList(); } 回答1: That's what the varchar type is for, to trim spaces automatically, and efficiently. Manual trim() operations have

问题 When I create a new Dev Express XAF application using the wizard 20.1.3 for .netcore3.1 the code works fine. I can enable migrations and run a migration without problems. (Or so I thought ... see below) However for certain reasons (my legacy call run-migrations code) I want to provide the connection string location to the constructor When I do this, and try to add a migratiion I get an error The DbContext is set up as using System; using System.Data.Entity; using System.Data.Common; using

问题 When I create a new Dev Express XAF application using the wizard 20.1.3 for .netcore3.1 the code works fine. I can enable migrations and run a migration without problems. (Or so I thought ... see below) However for certain reasons (my legacy call run-migrations code) I want to provide the connection string location to the constructor When I do this, and try to add a migratiion I get an error The DbContext is set up as using System; using System.Data.Entity; using System.Data.Common; using

问题 Why is in the following example the [NotMapped] attribute required: public virtual ICollection<Blog> Blogs { get; set; } [NotMapped] public List<Blog> NewBlogs{ get{ return Blogs.Where(x=>x.Date > DateTime.Now).ToList(); } } Without the [NotMapped] attribute I get an exception: Invalid column name Blog_ID The column name in the database is BlogID. EDIT I would expect, that properties without setter are never directly mapped to the database and automatically ignored by code first. 回答1: with

问题 I have just finished modifying my models, ran "Update-Database" in the package manager console and BOOM! I received a "Sequence contains more than one element" error. Upon scanning through the console, it did say No pending explicit migrations. which is obviously wrong since I renamed some models. I also found a SingleOrDefault call I don't know where it came from. I commented out my seed method so that's not causing it No pending explicit migrations. System.InvalidOperationException:

问题 I have just finished modifying my models, ran "Update-Database" in the package manager console and BOOM! I received a "Sequence contains more than one element" error. Upon scanning through the console, it did say No pending explicit migrations. which is obviously wrong since I renamed some models. I also found a SingleOrDefault call I don't know where it came from. I commented out my seed method so that's not causing it No pending explicit migrations. System.InvalidOperationException:

问题 I need to make several changes in my database in my controller. foreach (var valueStream in model.ListValueStream) { ValueStreamProduct vsp = new ValueStreamProduct(valueStream.Id, product.Id); db.ValueStreamProduct.Add(vsp); } db.SaveChanges(); Shoul I call SaveChanges at the end or each time I make changes? 回答1: It depends. With each change - If you want each save to run in its own transaction and be independent of other changes then run the save in the loop or after you make a change. Note

问题 I am stumped - upgrading to Entity Framework 7 and I typically override the SaveChanges inside the DbContext to be able to get a list of all the Modified Objects before it changes. Ultimately I have a script that fires that tracks the previous version in a database. In Entity Framework 6 I would get the model changes like so: var oc = ((IObjectContextAdapter)this).ObjectContext; var modifiedItems = oc.ObjectStateManager.GetObjectStateEntries(EntityState.Modified | EntityState.Deleted); List

问题 I have the query: var query = DataContext.Fotos.Where(x => x.Pesquisa.Contais("myTerm") The SQL generated is: SELECT ... FROM Fotos AS [Extent1] WHERE [Extent1].[Pesquisa] LIKE N'%mytem%' But I need to use: SELECT ... FROM Fotos AS [Extent1] WHERE CONTAINS ([Extent1].[Pesquisa], 'my term') How to execute a full text search using entity framework 6? 回答1: Seems that Entity Framework 6 does not support full text search, but there is a workaround with interceptors. http://www.entityframework.info