c# - 使用 Entity Framework 自动编号

Question

我想遍历一组对象并将它们全部添加到一个表中。目标表有一个自增字段。如果我添加单个对象，则没有问题。如果我添加两个主键都为零的对象， Entity Framework 将失败。我可以手动指定主键，但尝试 EF 的全部目的是让生活更轻松而不是更复杂。这是代码，随后收到异常。

foreach (Contact contact in contacts)
{               
    Instructor instructor = InstructorFromContact(contact);             
    context.AddToInstructors(instructor);               
}

try
{                   
    context.SaveChanges();                  
}
catch (Exception ex)
{
    Console.WriteLine(ex.ToString());
}

错误是:

System.InvalidOperationException: The changes to the database were committed successfully, but an error occurred while updating the object context. The ObjectContext might be in an inconsistent state. Inner exception message: AcceptChanges cannot continue because the object's key values conflict with another object in the ObjectStateManager. Make sure that the key values are unique before calling AcceptChanges. at System.Data.Objects.ObjectContext.SaveChanges(SaveOptions options)
at System.Data.Objects.ObjectContext.SaveChanges() at DataMigration.Program.CopyInstructors() in C:\Projects\DataMigration\Program.cs:line 52

Answer 1

在自动增量字段的 SSDL 中将 StoreGeneratedPattern 属性设置为“Identity”。它应该有所帮助。