【发布时间】：2017-03-02 09:48:19
【问题描述】：
我正在使用 Xamarin.Forms 和便携式类库构建一个应用程序。该应用程序可以在 Android、iOS 和 UWP 上使用。
我一直在构建一个现在可以在 Android 和 UWP 上运行的数据库。当我使用相同的代码并在 iOS 上运行它时，它会给我一些错误。
这是异常消息：
未处理的异常：SQLite.SQLiteException：损坏
这是 StackTrace：
at SQLite.PreparedSqlLiteInsertCommand.ExecuteNonQuery (System.Object[] source) [0x00116] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2480
at SQLite.SQLiteConnection.Insert (System.Object obj, System.String extra, System.Type objType) [0x0010e] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:1381
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:143
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00047] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x0002e] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x0000b] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357
at App2.Model.Database.FormDAO+<InsertItem>d__2.MoveNext () [0x00066] in D:\SourceTree\App2\App2\Model\Database\FormDAO.cs:25
这是未处理异常所在的代码：
public async void InsertItem(Form Form)
{
try
{
var result = await Task.Factory.StartNew(() => database.Insert(Form)); //this line
} catch(Exception e)
{
Debug.WriteLine("e.message" + e.Message + ";;;;" + e.StackTrace);
}
}
函数 InsertItem(form) 从另一个异步方法调用了大约 1000 次。
为什么这段代码在 iOS 上不起作用？
编辑： 我得到的其他错误是：
SQLite.SQLiteException: IOError
堆栈跟踪：
at SQLite.PreparedSqlLiteInsertCommand.ExecuteNonQuery (System.Object[] source) [0x00116] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2480
at SQLite.SQLiteConnection.Insert (System.Object obj, System.String extra, System.Type objType) [0x0010e] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:1381
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:143
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess (System.Threading.Tasks.Task task) [0x00047] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:187
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification (System.Threading.Tasks.Task task) [0x0002e] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:156
at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd (System.Threading.Tasks.Task task) [0x0000b] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:128
at System.Runtime.CompilerServices.TaskAwaiter`1[TResult].GetResult () [0x00000] in /Users/builder/data/lanes/3818/ad1cd42d/source/xamarin-macios/_ios-build/Library/Frameworks/Xamarin.iOS.framework/Versions/git/src/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/TaskAwaiter.cs:357
at App2.Model.Database.CourseDAO+<InsertItem>d__2.MoveNext () [0x00055] in D:\SourceTree\App2\App2\Model\Database\CourseDAO.cs:26
使用几乎相同的方法但使用这一行时会引发此异常：
var result = await Task.Factory.StartNew(() => database.Insert(Course));
【问题讨论】：
-
The database disk image is malformed：尝试从设备/模拟器中手动删除应用程序以删除数据库并重试。您可能想看看通过队列序列化您的数据库操作与在不同的任务/线程上执行这些插入。 -
@SushiHangover 你有通过队列序列化数据库操作的例子吗？
-
使用 ConcurrentQueue 添加您的“课程”。创建一个任务，尝试从队列中获取对象并插入数据库。此任务将序列化写入数据库。异步写入队列，但不要异步写入数据库。
标签： c# ios sqlite xamarin xamarin.ios