执行LINQ时未找到行或更改错误

Question

这是我的代码

        using (BatchDashboardDataContext db = new BatchDashboardDataContext())
        {
            TBatchDashboard b = new TBatchDashboard();

            b.Id = deletedBatchId;
            db.TBatchDashboards.Attach(b);
            db.TBatchDashboards.DeleteOnSubmit(b);
            db.SubmitChanges();
        }

Id是TBatchDashboard表的主键。还有一个记录deletedBatchId值作为TBatchDashboard表中的主键。 请检查它给我建议。 感谢。