c# - 如何使用表中的嵌套类和列表？

标签 c# sqlite xamarin sqlite-net sqlite-net-extensions

我正在使用SQLite as a database我有下表，当我创建它时它可以工作:

public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }
    public Gender Gender { get; set; }
    public DateTime? DateOfBirth { get; set; }
}

创建表时

database.CreateTableAsync<TodoItem>().Wait();

现在，如果我想包含嵌套对象，我会收到一些错误:

public class Test
{
    [PrimaryKey, AutoIncrement]
    public int AnotherID { get; set; }
    public string Name { get; set; }
}
public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }
    public Gender Gender { get; set; }
    public DateTime? DateOfBirth { get; set; }
    public Test Test { get; set; }
}

我收到以下错误

UNHANDLED EXCEPTION:
 System.AggregateException: One or more errors occurred. ---> System.NotSupportedException: Don't know about Todo.Test
   at SQLite.Orm.SqlType (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x001ad] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2080 
   at SQLite.Orm.SqlDecl (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2027 
   at SQLite.SQLiteConnection.<CreateTable>m__0 (SQLite.TableMapping+Column p) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:417 
   at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/Select.cs:251 
   at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00015] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/ToCollection.cs:19 
   at SQLite.SQLiteConnection.CreateTable (System.Type ty, SQLite.CreateFlags createFlags) [0x00133] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:418 
   at SQLite.SQLiteAsyncConnection+<CreateTablesAsync>c__AnonStorey0.<>m__0 () [0x0002f] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLiteAsync.cs:108 
   at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x0000f] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 
   at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 
    --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00011] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2157 
   at System.Threading.Tasks.Task.Wait (System.Int32 millisecondsTimeout, System.Threading.CancellationToken cancellationToken) [0x00043] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3189 
   at System.Threading.Tasks.Task.Wait () [0x00000] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3054 
   at Todo.TodoItemDatabase..ctor (System.String dbPath) [0x00015] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\Data\TodoItemDatabase.cs:14 
   at Todo.App.get_Database () [0x0000e] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\App.cs:32 
   at Todo.TodoListPage+<OnAppearing>d__1.MoveNext () [0x0002c] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\Views\TodoListPage.xaml.cs:20 
 --- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:151 
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018 
   at Android.App.SyncContext+<>c__DisplayClass2_0.<Post>b__0 () [0x00000] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/Android.App/SyncContext.cs:35 
   at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/Java.Lang/Thread.cs:36 
   at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/obj/Release/android-23/mcw/Java.Lang.IRunnable.cs:81 
   at (wrapper dynamic-method) System.Object:4ad81135-c1dd-4bba-bca3-4e991f58da69 (intptr,intptr)
 ---> (Inner Exception #0) System.NotSupportedException: Don't know about Todo.Test
   at SQLite.Orm.SqlType (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x001ad] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2080 
   at SQLite.Orm.SqlDecl (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2027 
   at SQLite.SQLiteConnection.<CreateTable>m__0 (SQLite.TableMapping+Column p) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:417 
   at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/Select.cs:251 
   at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00015] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/ToCollection.cs:19 
   at SQLite.SQLiteConnection.CreateTable (System.Type ty, SQLite.CreateFlags createFlags) [0x00133] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:418 
   at SQLite.SQLiteAsyncConnection+<CreateTablesAsync>c__AnonStorey0.<>m__0 () [0x0002f] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLiteAsync.cs:108 
   at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x0000f] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 
   at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 <---

如果我使用列表 

public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }
    public Gender Gender { get; set; }
    public DateTime? DateOfBirth { get; set; }
    public List<string> Strings { get; set; }
}

我明白了

 UNHANDLED EXCEPTION:
 System.AggregateException: One or more errors occurred. ---> System.NotSupportedException: Don't know about System.Collections.Generic.List`1[System.String]
   at SQLite.Orm.SqlType (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x001ad] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2080 
   at SQLite.Orm.SqlDecl (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2027 
   at SQLite.SQLiteConnection.<CreateTable>m__0 (SQLite.TableMapping+Column p) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:417 
   at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/Select.cs:251 
   at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00015] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/ToCollection.cs:19 
   at SQLite.SQLiteConnection.CreateTable (System.Type ty, SQLite.CreateFlags createFlags) [0x00133] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:418 
   at SQLite.SQLiteAsyncConnection+<CreateTablesAsync>c__AnonStorey0.<>m__0 () [0x0002f] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLiteAsync.cs:108 
   at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x0000f] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 
   at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 
    --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional (System.Boolean includeTaskCanceledExceptions) [0x00011] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2157 
   at System.Threading.Tasks.Task.Wait (System.Int32 millisecondsTimeout, System.Threading.CancellationToken cancellationToken) [0x00043] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3189 
   at System.Threading.Tasks.Task.Wait () [0x00000] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:3054 
   at Todo.TodoItemDatabase..ctor (System.String dbPath) [0x00015] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\Data\TodoItemDatabase.cs:14 
   at Todo.App.get_Database () [0x0000e] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\App.cs:32 
   at Todo.TodoListPage+<OnAppearing>d__1.MoveNext () [0x0002c] in C:\Users\some-user\Documents\Visual Studio 2015\Projects\Todo\Todo\Views\TodoListPage.xaml.cs:20 
 --- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () [0x0000c] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/runtime/exceptionservices/exceptionservicescommon.cs:151 
   at System.Runtime.CompilerServices.AsyncMethodBuilderCore+<>c.<ThrowAsync>b__6_0 (System.Object state) [0x00000] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/runtime/compilerservices/AsyncMethodBuilder.cs:1018 
   at Android.App.SyncContext+<>c__DisplayClass2_0.<Post>b__0 () [0x00000] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/Android.App/SyncContext.cs:35 
   at Java.Lang.Thread+RunnableImplementor.Run () [0x00008] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/Java.Lang/Thread.cs:36 
   at Java.Lang.IRunnableInvoker.n_Run (System.IntPtr jnienv, System.IntPtr native__this) [0x00008] in /Users/builder/data/lanes/4695/448f54fd/source/xamarin-android/src/Mono.Android/obj/Release/android-23/mcw/Java.Lang.IRunnable.cs:81 
   at (wrapper dynamic-method) System.Object:3ff99a1f-7842-4c41-b229-386570e8d19f (intptr,intptr)
 ---> (Inner Exception #0) System.NotSupportedException: Don't know about System.Collections.Generic.List`1[System.String]
   at SQLite.Orm.SqlType (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x001ad] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2080 
   at SQLite.Orm.SqlDecl (SQLite.TableMapping+Column p, System.Boolean storeDateTimeAsTicks) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:2027 
   at SQLite.SQLiteConnection.<CreateTable>m__0 (SQLite.TableMapping+Column p) [0x00000] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:417 
   at System.Linq.Enumerable+SelectArrayIterator`2[TSource,TResult].ToArray () [0x00012] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/Select.cs:251 
   at System.Linq.Enumerable.ToArray[TSource] (System.Collections.Generic.IEnumerable`1[T] source) [0x00015] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/external/corefx/src/System.Linq/src/System/Linq/ToCollection.cs:19 
   at SQLite.SQLiteConnection.CreateTable (System.Type ty, SQLite.CreateFlags createFlags) [0x00133] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLite.cs:418 
   at SQLite.SQLiteAsyncConnection+<CreateTablesAsync>c__AnonStorey0.<>m__0 () [0x0002f] in /Users/fak/Dropbox/Projects/sqlite-net/src/SQLiteAsync.cs:108 
   at System.Threading.Tasks.Task`1[TResult].InnerInvoke () [0x0000f] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Future.cs:680 
   at System.Threading.Tasks.Task.Execute () [0x00010] in /Users/builder/jenkins/workspace/xamarin-android/xamarin-android/external/mono/mcs/class/referencesource/mscorlib/system/threading/Tasks/Task.cs:2502 <---

我正在使用SQLite-net Official Portable Library 1.3.3 。我是否必须使用 PrimaryKey、ForeignKey 等属性？如何？或者该库只能处理原始数据类型？

示例可以从here下载.

This issue声明，应该可以使用 List，但不能在最新版本中使用。我尝试降级到 1.2.0 和 1.3.1，但没有成功。

编辑

我安装了SQLiteNetExtensions并将示例代码更改为

using SQLite;
using SQLiteNetExtensions.Attributes;
using System.Collections.Generic;

namespace Todo
{
    public class Test
    {
        [PrimaryKey, AutoIncrement]
        public int AnotherID { get; set; }
        public string Name { get; set; }
    }

    public class TodoItem
    {
        [PrimaryKey, AutoIncrement]
        public int ID { get; set; }
        public string Name { get; set; }
        public string Notes { get; set; }
        public bool Done { get; set; }
        [TextBlob("StringsBlobbed")]
        public List<string> Strings { get; set; }
        public string StringsBlobbed { get; set; }
    }
}

我仍然遇到同样的错误。

编辑2

我认为图书馆之间存在混淆。 SQLite-Net 扩展 取决于 SQLite.Net-PCL v. 3.1.1 (Nuget)。但 Xamarin 链接到库 sqlite-net-pcl v. 1.3.3 (Nuget)。

SQLite.Net-PCL (oysteinkrog) 是 sqlite-net-pcl (praeclarum) 的一个分支)。看来后一个与SQLite-Net Extensions不兼容，而这正是我这里需要的。但是 SQLite.Net-PCL 支持 UWP 吗？它自 2016 年 6 月 4 日起就没有更新过。最有趣的是 SQLite-Net Extensions 链接到 praeclarum ，这是错误的。我通过卸载所有 SQL Nuget 包并仅安装 SQLite-Net Extensions 来检查这一点，这应该会自动触发所需的依赖项。我能做什么？

最佳答案

能够使用嵌套 List或object我需要SQLiteNetExtensions 。因为我正在使用another SQLite package比default dependency的SQLiteNetExtensions您有两个选择:

  1. 手动将项目添加到您的解决方案
    1.1.下载SQLiteNetExtensions的源代码
    1.2.将“SQLiteNetExtensions-PCL”项目添加到您的解决方案
    1.3.添加此项目作为所有项目(可移植、iOS、Droid、UWP)的引用

  2. Install SQLiteNetExtensions 2.0.0-alpha2

请注意您是否已经安装了一些 sql NuGet 包。先全部卸载然后只安装SQLiteNetExtensions 。这将为您添加所有必需的依赖项。

对于List<string>你可以这样做:

public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }

    [TextBlob("StringsBlobbed")]
    public List<string> Strings { get; set; }
    public string StringsBlobbed { get; set; }
}

如果您有其他类型的列表，则需要 [OneToMany]关系。

要使用对象，您应该能够 to do this :

public class Test
{
    [PrimaryKey, AutoIncrement]
    public string AnotherID { get; set; }
    public string Name { get; set; }
}

public class TodoItem
{
    [PrimaryKey, AutoIncrement]
    public int ID { get; set; }
    public string Name { get; set; }
    public string Notes { get; set; }
    public bool Done { get; set; }

    [ForeignKey(typeof(Test))]
    public string TestId { get; set; }

    [OneToOne]
    public Test Test { get; set; }
}

如何使用 [OneToOne] 的良好指南关系(例如对象)是 this here 。对于 [OneToMany]看here .

还有一些步骤，例如创建表以及以特殊方式检索和存储数据( GetWithChildren 、 UpdateWithChildren 、...)。另请注意 CascadeOperations ，如果您有多级层次结构，您将需要它。

如果仍然出现错误，请仔细阅读调试日志。人们必须确保[ForeignKey]和[OneToOne]用于所有使用该对象的类。

关于c# - 如何使用表中的嵌套类和列表？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44672611/

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