Store update, insert, or delete statement affected an unexpected number of rows (0) EntityFramework [duplicate]

Answer 1

I don't know what exactly was wrong but i just did these steps and it got resolved. (I hope you will be able to resolve this as i was able to do it)
Steps are as follows:
(1) Add the new controller using scaffolding on the basis of your edmx table and the DB context of EF file.
(2) Now where the save changes creates the problem is edit method.
(3) Now copy the edit method/ whole controller made out of scaffolding and paste it in your original controller.
(4) now just build the program and Voila you are good to go.

Update
I found out that for data to be edited from view all the fields must be sent for written again to controller. If at the time of edition any of the fields from entity table is missing it will not allow to be editted. Especially if PK is in Label and sent to controller for edit then it will generate this error.

Answer 2

Thanks Terry, Let's add this: Do NOT add [Required] attribute to your Key/ID when scaffolding. This stops your context from pulling the key/id from the url. Also: This happened to me in a scaffold controller after a migration which included new boolean fields on the model. These fields were not set.

Answer 3

I encountered this error when creating a project, even just trying to do a simple insert.

We were generating the EF model from a pre-existing database, and the framework automatically set Entity Key = True on multiple fields.

Setting all but the ID to False solved the problem.

Answer 4

Well, I also faced this type of concurrency error while working with Entity Framework 6.13 using Code First. And I also struggled for hours before solving it myself. So it can help someone out there. A table was created with composite primary keys and today I changed the structure of the table and made only one primary key(with AutoIncrement) instead of composite keys and update the table through migrations with fluent-api configurations. Table got updated but the primary key was not updated with AutoIncrement and whenever I tried to add a record, it showed the concurrency error. So, as I set the autoincrement of the field and the error was gone. Hope, it helps.