I think this is solved by Tillito: Entity Framework and SQL Server View I’ll quote his entry below: We had the same problem and this is the solution: To force entity framework to use a column as a primary key, use ISNULL. To force entity framework not to use a column as a primary key, … Read more
You can use Include() first, then retrieve a single object from the resulting query: Item item = db.Items .Include(i => i.Category) .Include(i => i.Brand) .FirstOrDefault(x => x.ItemId == id);
These articles might be of interest…the series really gets into the advantages and disadvantages of a POCO approach. Link Link Link In these articles the author mentions future articles that describe best practices in implementing Repository and Unit of Work patterns, but I can’t find them. These articles are well written and I’d like to … Read more
For me apparently it worked once I have also ran in Package Manager console : Install-Package Microsoft.EntityFrameworkCore.Tools Also make sure : To have other dependencies (for example Microsoft.EntityFrameworkCore, Microsoft.EntityFrameworkCore.SqlServer, Microsoft.EntityFrameworkCore.SqlServer.Design…) referenced depending of your needs. To select the right assembly as target for your commands in the top-right corner of the PM console (I am … Read more
This cannot work because ppCombined is a collection of objects in memory and you cannot join a set of data in the database with another set of data that is in memory. You can try instead to extract the filtered items personProtocol of the ppCombined collection in memory after you have retrieved the other properties … Read more
It seems that there are circular references in your object hierarchy which is not supported by the JSON serializer. Do you need all the columns? You could pick up only the properties you need in the view: return Json(new { PropertyINeed1 = data.PropertyINeed1, PropertyINeed2 = data.PropertyINeed2 }); This will make your JSON object lighter and … Read more
I am not sure if you are using IoC and Dependency Injection to resolve your DbContext where ever it might be used. If you do and you are using native IoC from .NET Core (or any other IoC-Container) and you are getting this error, make sure to register your DbContext as Transient. Do services.AddDbContext<MyContext>(ServiceLifetime.Transient); OR … Read more
This is an option: dbContext.Entry(entity).State = EntityState.Detached;
Because these two lines … EmployeeService es = new EmployeeService(); CityService cs = new CityService(); … don’t take a parameter in the constructor, I guess that you create a context within the classes. When you load the city1… Payroll.Entities.City city1 = cs.SelectCity(…); …you attach the city1 to the context in CityService. Later you add a … Read more
I had this same error for a while in a slightly different scenario. The cause was invalid XAML, because some tags were missing. I had <wpftoolkit:DataGrid AutoGenerateColumns=”False” ItemsSource=”{Binding Path=Accounts}” > <wpftoolkit:DataGridTextColumn Header=”Account Name” Binding=”{Binding Path=AccountName}” /> </wpftoolkit:DataGrid> which I fixed to be <wpftoolkit:DataGrid AutoGenerateColumns=”False” ItemsSource=”{Binding Path=Accounts}” > <wpftoolkit:DataGrid.Columns> <wpftoolkit:DataGridTextColumn Header=”Account Name” Binding=”{Binding Path=AccountName}” /> </wpftoolkit:DataGrid.Columns> … Read more