Insert a copy of existing row using Linq to Entities [closed]

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Closed 5 years ago.

I am using entity framework. I have a table with auto generated primary key and lot of foriegn key relationship with other master data tables. We need a copy functionality, wherein we can select any existing row from the table and insert that as a copy in the same table.

I need to copy all the fields, but it should be a different record, and need the procedure/LINQ for same.

Please suggest, how should I proceed.

回答1:

You can do this:

context.Entry(oCustomer).State = EntityState.Added;

this will cause EF to think this entity is a new one and after you call SaveChanges it will be inserted in the database and not updated.

If you have an object graph - you need to traverse it and make sure all child entities are set to EntityState.Unchanged or they will be duplicated after SaveChanges.

来源：https://stackoverflow.com/questions/20322778/insert-a-copy-of-existing-row-using-linq-to-entities