清理数据库缓存

using (var db = new MyDataContext())
                {
                    if (db.DatabaseExists())
                    {
                        var mystamp = long.Parse(GetTimeStamp(DateTime.Now.AddDays(-15)));
                        IQueryable<MyContent> contentdb = from s in db.MyContents
                            where s.stamp < mystamp
                            select s;
                        db.MyContents.DeleteAllOnSubmit(contentdb);
                        db.SubmitChanges();
                    }
                }

using (IsolatedStorageFile.GetUserStoreForApplication())
                    if (IsolatedStorageFile.GetUserStoreForApplication().FileExists("MyDb.sdf"))
                        IsolatedStorageFile.GetUserStoreForApplication().DeleteFile("MyDb.sdf");
                using (var db = new MyDataContext())
                {
                    switch (db.DatabaseExists())
                    {
                        case false:
                            db.CreateDatabase();
                            Debug.WriteLine(DateTime.Now.ToLongTimeString() + "数据库创建完成");
                            break;
                        default:
                            Debug.WriteLine("数据库已经存在");
                            break;
                    }
                }
                PublicMethod.Showtoast("清理成功~");