Question

几天后，我一直在使用Parse.com将数据同步到云端。我现在正在编写所有函数来从云中获取所有数据并将其与本地SQLite数据库同步。

我使用ParseObject从云中获取所有数据：

 var taskQuery = from TaskTable in ParseObject.GetQuery("Task")
                           where TaskTable.Get<Boolean>("Deleted") == false
                           where TaskTable.Get<DateTime>("updatedAt") > SqliteSyncDate
                           select TaskTable;
 IEnumerable<ParseObject> tasks = await taskQuery.FindAsync();

将其放入ParseObject后，我用foreach循环播放，但我遇到了问题。我有一个表Task，其中有一个字段UserId，我将其定义为表Pointer的{{1}}。我现在必须将此Login存储在我的SQLite数据库中，但我不知道如何解析＆＃39;和/或现在在本地保存。我的代码：

Pointer

如果我在没有try catch的情况下运行它，我将收到以下错误：

//Loop over every record that is returned from Parse.com
        foreach (ParseObject task in tasks)
        {
            try
            {
                //Create new record to add to Task
                Tasks taskSqlite = new Tasks();
                taskSqlite.Id = task.Get<int>("Id");
                //This line fails! When I comment it out syncing works, otherwise it doesn't.
                taskSqlite.UserId = task.Get<int>("UserId");
                taskSqlite.Description = task.Get<string>("Description");
                taskname = task.Get<string>("Description");
                taskSqlite.Date = task.Get<DateTime?>("Date");
                taskSqlite.Done = task.Get<Boolean>("Done");
                taskSqlite.DoneBy = task.Get<string>("DoneBy");
                taskSqlite.Deleted = task.Get<Boolean>("Deleted");
                taskSqlite.LastModified = task.Get<DateTime?>("LastModified");

                //And finally insert the record in to the SQLite database.
                DATask.InsertTask(taskSqlite);
            }
            catch
            {
                Debug.WriteLine("SYNC FAILURE - failed on table Task on the task: " + taskname);
            }

更新：正如我所指出的，我决定也打印Exception。这是例外：

03-31 16:37:52.676 I/MonoDroid( 4731): UNHANDLED EXCEPTION:
03-31 16:37:52.697 I/MonoDroid( 4731): System.NullReferenceException: Object reference not set to an instance of an object

然后我创建了一个Exception: System.InvalidCastException: Value is not a convertible object: Parse.ParseObject to System.Int32 03-31 17:03:18.335 I/mono-stdout( 8270): SYNC FAILURE - failed on table Task on the task: Exception: System.InvalidCastException: Value is not a convertible object: Parse.ParseObject to System.Int32 [0:] SYNC FAILURE - failed on table Task on the task: Exception: System.InvalidCastException: Value is not a convertible object: Parse.ParseObject to System.Int32 at System.Convert.ToType (System.Object value, System.Type conversionType, IFormatProvider provider, Boolean try_target_to_type) [0x00000] in <filename unknown>:0 at System.Convert.ChangeType (System.Object value, System.Type conversionType) [0x00000] in <filename unknown>:0 at Parse.ParseClient.ConvertTo[Int32] (System.Object value) [0x00000] in <filename unknown>:0 at Parse.ParseObject.Get[Int32] (System.String key) [0x00000] in <filename unknown>:0。但是，我现在怎样才能将UserId从中获取？

ParseRelation

那么我应该如何转换它或将其保存到SQLite数据库中呢？这是将记录链接到彼此的正确方法吗？

Answer 1

似乎你遇到int类型的问题。也许尝试Int32或其他什么？如果这没有帮助，您可以检查数据库中的值。也许UserId不是可以转换为int的数值？

Answer 2

对不起，迟到的回复

presentViewController

应该做的伎俩

将指针从Parse.com记录到SQLite表中

2 个答案: