你可以在网格的点击或celldoubleclick事件中这样做(如果你使用了一个)

if(dgEmp.CurrentRow.Index != -1)
 {
    employ.Id = (Int32)dgEmp.CurrentRow.Cells["Id"].Value;
    //Some other stuff here
 }

然后在删除按钮中执行如下操作:

using(Context context = new Context())
{
     var entry = context.Entry(employ);
     if(entry.State == EntityState.Detached)
     {
        //Attached it since the record is already being tracked
        context.Employee.Attach(employ);
     }                             
     //Use Remove method to remove it virtually from the memory               
     context.Employee.Remove(employ);
     //Finally, execute SaveChanges method to finalized the delete command 
     //to the actual table
     context.SaveChanges();

     //Some stuff here
}

或者，你可以使用LINQ查询，而不是使用LINQ到实体查询:

var query = (from emp in db.Employee
where emp.Id == employ.Id
select emp).Single();

雇佣。Id用作过滤参数，它已经从DataGridView的CellDoubleClick事件中传递。

更普通的approuch

public virtual void Delete<T>(int id) where T : BaseEntity, new()
{
    T instance = Activator.CreateInstance<T>();
    instance.Id = id;
    if (dbContext.Entry<T>(entity).State == EntityState.Detached)
    {
        dbContext.Set<T>().Attach(entity);
    }

    dbContext.Set<T>().Remove(entity);
}

您可以使用SingleOrDefault获取与您的条件匹配的单个对象，然后将其传递给EF表的Remove方法。

var itemToRemove = Context.Employ.SingleOrDefault(x => x.id == 1); //returns a single item.

if (itemToRemove != null) {
    Context.Employ.Remove(itemToRemove);
    Context.SaveChanges();
}

不需要先查询对象，可以通过它的id将它附加到上下文。 是这样的:

var employer = new Employ { Id = 1 };
ctx.Employ.Attach(employer);
ctx.Employ.Remove(employer);
ctx.SaveChanges();

或者，你可以将附加条目的状态设置为已删除:

var employer = new Employ { Id = 1 };
ctx.Entry(employer).State = EntityState.Deleted;
ctx.SaveChanges();

Employer employer = context.Employers.First(x => x.EmployerId == 1);

context.Customers.DeleteObject(employer);
context.SaveChanges();

这里有一个安全的方法:

using (var transitron = ctx.Database.BeginTransaction())
{
  try
  {
    var employer = new Employ { Id = 1 };
    ctx.Entry(employer).State = EntityState.Deleted;
    ctx.SaveChanges();
    transitron.Commit();
  }
  catch (Exception ex)
  {
    transitron.Rollback();
    //capture exception like: entity does not exist, Id property does not exist, etc...
  }
}

在这里，您可以堆积您想要的所有更改，因此您可以在SaveChanges和Commit之前执行一系列删除操作，因此只有当它们都成功时才会应用它们。