安卓使用sqlite一点问题都没， 但是ios就是不行。 因为之前一直用的是mssql，所以都没仔细测试过sqlite

[densen2014]

安卓使用sqlite一点问题都没， 但是ios就是不行。 因为之前一直用的是mssql，所以都没仔细测试过sqlite。 难道当时调试没测试过ios的sqlite？以下是使用最新的源码以及以前你给我的app工程文件调试的。

主库数据库出错（执行SQL）〓〓〓〓〓〓〓〓〓〓〓〓〓〓〓
select 1 from main.sqlite_master where type='table' and name='Item'
【主库】状态不可用，等待后台检查程序恢复方可使用。Object reference not set to an instance of an object
System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.Exception: 【主库】状态不可用，等待后台检查程序恢复方可使用。Object reference not set to an instance of an object
at FreeSql.Internal.CommonProvider.CodeFirstProvider.SyncStructure (System.ValueTuple`2[System.Type,System.String][] objects) [0x00167] in :0
at FreeSql.Internal.CommonProvider.CodeFirstProvider.SyncStructure[TEntity] () [0x0001d] in :0
at App3.Services.MockDataStore..ctor () [0x00008] in /Users/alex/Desktop/testxmarin/App3/App3/Services/MockDataStore.cs:47
at (wrapper managed-to-native) System.Reflection.RuntimeConstructorInfo.InternalInvoke(System.Reflection.RuntimeConstructorInfo,object,object[],System.Exception&)
at System.Reflection.RuntimeConstructorInfo.InternalInvoke (System.Object obj, System.Object[] parameters, System.Boolean wrapExceptions) [0x00005] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/corlib/System.Reflection/RuntimeMethodInfo.cs:936
--- End of inner exception stack trace ---
at System.Reflection.RuntimeConstructorInfo.InternalInvoke (System.Object obj, System.Object[] parameters, System.Boolean wrapExceptions) [0x00018] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/corlib/System.Reflection/RuntimeMethodInfo.cs:944
at System.RuntimeType.CreateInstanceMono (System.Boolean nonPublic, System.Boolean wrapExceptions) [0x00095] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/corlib/ReferenceSources/RuntimeType.cs:185
at System.RuntimeType.CreateInstanceSlow (System.Boolean publicOnly, System.Boolean wrapExceptions, System.Boolean skipCheckThis, System.Boolean fillCache) [0x00009] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/corlib/ReferenceSources/RuntimeType.cs:155
at System.RuntimeType.CreateInstanceDefaultCtor (System.Boolean publicOnly, System.Boolean skipCheckThis, System.Boolean fillCache, System.Boolean wrapExceptions, System.Threading.StackCrawlMark& stackMark) [0x00027] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/rttype.cs:5770
at System.Activator.CreateInstance (System.Type type, System.Boolean nonPublic, System.Boolean wrapExceptions) [0x00039] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/activator.cs:206
at System.Activator.CreateInstance (System.Type type, System.Boolean nonPublic) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/activator.cs:190
at System.Activator.CreateInstance (System.Type type) [0x00000] in /Library/Frameworks/Xamarin.iOS.framework/Versions/Current/src/Xamarin.iOS/mcs/class/referencesource/mscorlib/system/activator.cs:134
at Xamarin.Forms.DependencyService.Get[T] (Xamarin.Forms.DependencyFetchTarget fetchTarget) [0x00099] in D:\a\1\s\Xamarin.Forms.Core\DependencyService.cs:52
at App3.ViewModels.BaseViewModel.get_DataStore () [0x00000] in /Users/alex/Desktop/testxmarin/App3/App3/ViewModels/BaseViewModel.cs:15
at App3.ViewModels.ItemsViewModel.ExecuteLoadItemsCommand () [0x0004a] in /Users/alex/Desktop/testxmarin/App3/App3/ViewModels/ItemsViewModel.cs:42

1.使用
new FreeSql.FreeSqlBuilder() .UseConnectionString(FreeSql.DataType.Sqlite, connectionString) .UseAutoSyncStructure(true) .UseNoneCommandParameter(true) .UseMonitorCommand(cmd => Console.WriteLine(cmd.CommandText)) .Build());

报错

{System.NullReferenceException: Object reference not set to an instance of an object
at SQLitePCL.raw.sqlite3_open_v2 (SQLitePCL.utf8z filename, SQLitePCL.sqlite3& db, System.Int32 flags, SQLitePCL.utf8z vfs) [0x00000] in <15ecb38d58394d7b88b3f841a7dda078>:0
at SQLitePCL.raw.sqlite3_open_v2 (System.String filename, SQLitePCL.sqlite3& db, System.Int32 flags, System.String vfs) [0x0000e] in <15ecb38d58394d7b88b3f841a7dda078>:0
at Microsoft.Data.Sqlite.SqliteConnection.Open () [0x00122] in <99138fe6fbac4a1b964cb2ae266abca2>:0
at FreeSql.Sqlite.DbConnectionExtensions.OpenAndAttach (System.Data.Common.DbConnection that, System.String[] attach) [0x00001] in /Users/alex/Documents/GitHub/FreeSql/Providers/FreeSql.Provider.Sqlite/SqliteAdo/SqliteConnectionPool.cs:242
at FreeSql.Sqlite.SqliteConnectionPoolPolicy.OnGet (SafeObjectPool.Object`1[T] obj) [0x000ac] in /Users/alex/Documents/GitHub/FreeSql/Providers/FreeSql.Provider.Sqlite/SqliteAdo/SqliteConnectionPool.cs:151 }

2.和使用
new FreeSql.FreeSqlBuilder() .UseConnectionString(FreeSql.DataType.Sqlite, connectionString, typeof(FreeSql.Sqlite.SqliteProvider<>)) .UseAutoSyncStructure(true) .UseNoneCommandParameter(true) .UseMonitorCommand(cmd => Console.WriteLine(cmd.CommandText)) .Build());

报错

{System.NullReferenceException: Object reference not set to an instance of an object
at SQLitePCL.raw.sqlite3_open_v2 (SQLitePCL.utf8z filename, SQLitePCL.sqlite3& db, System.Int32 flags, SQLitePCL.utf8z vfs) [0x00000] in <15ecb38d58394d7b88b3f841a7dda078>:0
at SQLitePCL.raw.sqlite3_open_v2 (System.String filename, SQLitePCL.sqlite3& db, System.Int32 flags, System.String vfs) [0x0000e] in <15ecb38d58394d7b88b3f841a7dda078>:0
at Microsoft.Data.Sqlite.SqliteConnection.Open () [0x00122] in <99138fe6fbac4a1b964cb2ae266abca2>:0
at FreeSql.Sqlite.DbConnectionExtensions.OpenAndAttach (System.Data.Common.DbConnection that, System.String[] attach) [0x00001] in /Users/alex/Documents/GitHub/FreeSql/Providers/FreeSql.Provider.Sqlite/SqliteAdo/SqliteConnectionPool.cs:242
at FreeSql.Sqlite.SqliteConnectionPoolPolicy.OnGet (SafeObjectPool.Object`1[T] obj) [0x000ac] in /Users/alex/Documents/GitHub/FreeSql/Providers/FreeSql.Provider.Sqlite/SqliteAdo/SqliteConnectionPool.cs:151 }

[2881099]

System.NullReferenceException: Object reference not set to an instance of an object
at SQLitePCL.raw.sqlite3_open_v2 (SQLitePCL.utf8z filename, SQLitePCL.sqlite3& db, System.Int32 flags, SQLitePCL.utf8z vfs) [0x00000] in <15ecb38d58394d7b88b3f841a7dda078>:0
at SQLitePCL.raw.sqlite3_open_v2 (System.String filename, SQLitePCL.sqlite3& db, System.Int32 flags, System.String vfs) [0x0000e] in <15ecb38d58394d7b88b3f841a7dda078>:0
at Microsoft.Data.Sqlite.SqliteConnection.Open () [0x00122] in <99138fe6fbac4a1b964cb2ae266abca2>:0
at

手工使用 Microsoft.Data.Sqlite.SqliteConnection Open 试试会不会，Microsoft.Data.Sqlite 3.1.0

[densen2014]

经测试，是连接字串问题

测试代码：

var dir = Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "db111.db"); var dir4 = Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "db222.db"); var connv3 = new Microsoft.Data.Sqlite.SqliteConnection($"Data Source={dir};"); connv3.Open(); var connv4 = new Microsoft.Data.Sqlite.SqliteConnection($"Data Source={dir4};version=3"); connv4.Open();

测试结果，db111.db成功建立。连接字串不包含version=3即可

[densen2014]

真机还不能正确运行，微软这个反射的太混乱。暂时无结果

[densen2014]

使用1.1.0-preview6后，ios能正确使用sqlite了。但是以前能运行的 FreeSqlBuilder() 连接也必须加上类似 typeof(FreeSql.SqlServer.SqlServerProvider<>) ， 否则会报错。

[2881099]

使用1.1.0-preview6后，ios能正确使用sqlite了。但是以前能运行的 FreeSqlBuilder() 连接也必须加上类似 typeof(FreeSql.SqlServer.SqlServerProvider<>) ， 否则会报错。

这个是反射不到类型的表现，可能是项目包引用冲突

[densen2014]

1.1.0-preview6 最终运行方案：

1.主工程接口
public interface ISQLite
{
DbConnection GetConnection2();
}

3.安卓和ios分别平台分别引用Mono.Data.Sqlite，System.Data,实现 DbConnection GetConnection()

public DbConnection GetConnection2()
{
string MicrosoftdbPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Personal), "Microsoft.Data.Sqlite.db");
var connv3 = new Mono.Data.Sqlite.SqliteConnection($"Data Source={MicrosoftdbPath};");
//connv3.Open();
return connv3;
}

4.主工程最终获取连接，建立IFreeSql

IFreeSql _fsql = new FreeSql.FreeSqlBuilder()
.UseConnectionFactory(FreeSql.DataType.Sqlite, () => DependencyService.Get().GetConnection2(), typeof(FreeSql.Sqlite.SqliteProvider<>))
.UseAutoSyncStructure(true)
//.UseMonitorCommand(cmd => Console.WriteLine(cmd.CommandText))
.UseNoneCommandParameter(true)
.Build();

5.感谢叶老板无私帮助，奋战了xxx个日日夜夜，前几天工作忙，现在才总结一下写出来。愿跟我一样Xamarin开发者早日吃上freeSql这个全家桶，少走弯路。