Unir tablas en SQLite.Net con LINQ en xamarin.android no es compatible

me he atascado en un ensamblar y no puedo calcular hacia fuera donde está el problema, tengo esas tablas

public class Themes { [PrimaryKey, AutoIncrement] public int Id { get; set; } public String ThemeName { get; set; } public String ThemeDesc { get; set; } public int ThemeImg { get; set; } public String ThemeCategory { get; set; } public String ThemeSubcategory { get; set; } } public class MusicItems { [PrimaryKey, AutoIncrement] public int Id { get; set; } public String Name { get; set; } public String Tension { get; set; } public String Category { get; set; } public String Subcategory { get; set; } public int ResId { get; set; } public int LoopStart { get; set; } } public class Playlist { public String Name { get; set; } public int ResId { get; set; } public int LoopStart { get; set; } } public class MusicInThemes { [PrimaryKey, AutoIncrement] public int Id { get; set; } public int ResId { get; set; } public int ThemeId { get; set; } } 

Y quiero unirme a MusicItems con MusicInThemes para obtener todos los detalles de los archivos de música que pertenecen a un tema. Hasta ahora he probar estos que bloquean mi aplicación:

  var query = from MusicItem in database.Table<MusicItems>() join Theme in database.Table<MusicInThemes>() on MusicItem.ResId equals Theme.ResId where Theme.ThemeId == ThemeID select new Playlist{Name = MusicItem.Name, ResId = MusicItem.ResId ,LoopStart = 0}; return query.ToList(); // and return database.Table<MusicItems>() .Join(database.Table<MusicInThemes>().Where(t => t.ThemeId == ThemeID) ,m => m.ResId ,t => t.ResId ,(m,t) => new Playlist{Name = m.Name, ResId = m.ResId ,LoopStart = m.LoopStart}) .ToList(); 

Y este es el código donde obtuve la lista de reproducción: (Tengo 2 botones.La btnTheme1 mostrar algunas informaciones para el tema y guardar las variables del tema som y luego el botón loadTheme intenta extraer las canciones del tema seleccionado)

 ThemeImage = view.FindViewById<ImageView> (Resource.Id.imgThemeImage); ThemeDesc = view.FindViewById<TextView> (Resource.Id.txtDesc); Button btnTheme1 = view.FindViewById<Button> (Resource.Id.btnTheme1); //Button btnTheme2 = view.FindViewById<Button> (Resource.Id.btnTheme2); Button btnLoadTheme = view.FindViewById<Button> (Resource.Id.btnLoadTheme); musicFiles.AllThemes = mydata.GetAllThemes (); Console.WriteLine("Themes Count:"+musicFiles.AllThemes.Count); var ListSEbuttons = new List<Button> { { btnTheme1 }, }; for (i=0;i<ListSEbuttons.Count();i++){ var button = ListSEbuttons[i]; button.Text = SelectedThemeName = musicFiles.AllThemes [i].ThemeName; SelectedThemeImageId = musicFiles.AllThemes [i].ThemeImg; button.Tag = i; SelectedThemeId = musicFiles.AllThemes [i].Id; button.Click += ButtonOnClick; } btnTheme1.PerformClick (); btnLoadTheme.Click += (sender, e) => { Low = mydata.GetPlaylist(SelectedThemeId,"low"); // this is where the crash happens ... } private void ButtonOnClick(object sender, EventArgs eventArgs) { var button = sender as Button; if (button != null) { var index = (int)button.Tag; Console.WriteLine("List pos for sound effect: "+musicFiles.AllThemes [index].ThemeImg); button.RequestFocus(); ThemeDesc.Text = musicFiles.AllThemes [index].ThemeDesc; //ThemeImage.SetImageResource (musicFiles.AllThemes [index].ThemeImg); } } //ignore the "low" parameter i never use it for now 

Por favor aconséjame

 Debug Log: ... [Mono] Assembly Ref addref Music[0xb95c8210] -> Newtonsoft.Json[0xb95ca100]: 2 [Mono] The request to load the retargetable assembly mscorlib v2.0.5.0 was remapped to mscorlib v2.0.5.0 [Mono] Assembly Ref addref Newtonsoft.Json[0xb95ca100] -> mscorlib[0xb9406208]: 7 [Mono] Assembly Ref addref System.Core[0xb960c248] -> System[0xb972dd18]: 4 [MediaPlayer-JNI] MediaPlayer finalized without being released [MediaPlayer-JNI] MediaPlayer finalized without being released [MediaPlayer-JNI] MediaPlayer finalized without being released [MediaPlayer-JNI] MediaPlayer finalized without being released [Mono] GC_OLD_BRIDGE num-objects 44 num_hash_entries 47 sccs size 47 init 0.00ms df1 0.19ms sort 0.30ms dfs2 1.39ms setup-cb 0.01ms free-data 0.12ms links 3/3/3/1 dfs passes 94/50 [Mono] GC_MINOR: (Nursery full) pause 19.83ms, total 19.96ms, bridge 11.96ms promoted 784K major 1072K los 8K [Mono] GC_OLD_BRIDGE num-objects 44 num_hash_entries 47 sccs size 47 init 0.00ms df1 0.19ms sort 0.30ms dfs2 1.39ms setup-cb 0.01ms free-data 0.12ms links 0/0/0/0 dfs passes 0/0 [Mono] GC_MINOR: (Nursery full) pause 11.56ms, total 11.67ms, bridge 0.17ms promoted 368K major 1440K los 8K [] * Assertion at /Users/builder/data/lanes/monodroid-mlion-monodroid-4.20-series/ba9bbbdd/source/mono/mono/metadata/sgen-stw.c:68, condition `info->stack_start >= info->stack_start_limit && info->stack_start < info->stack_end' not met [mono-rt] Stacktrace: [mono-rt] [mono-rt] at <unknown> <0xffffffff> [mono-rt] at (wrapper managed-to-native) object.__icall_wrapper_mono_array_new_specific (intptr,int) <IL 0x00022, 0xffffffff> [mono-rt] at System.Collections.Concurrent.SplitOrderedList`2<string, System.Collections.Generic.KeyValuePair`2<string, SQLite.PreparedSqlLiteInsertCommand>>..ctor (System.Collections.Generic.IEqualityComparer`1<string>) <IL 0x00006, 0x0004b> [mono-rt] at System.Collections.Concurrent.ConcurrentDictionary`2..ctor (System.Collections.Generic.IEqualityComparer`1<TKey>) <IL 0x0000f, 0x000a6> [mono-rt] at System.Collections.Concurrent.ConcurrentDictionary`2..ctor () <IL 0x00006, 0x0006b> [mono-rt] at SQLite.TableMapping..ctor (System.Type,SQLite.CreateFlags) [0x0019d] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Helpers\SQLite.cs:1755 [mono-rt] at SQLite.SQLiteConnection.GetMapping (System.Type,SQLite.CreateFlags) [0x00036] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Helpers\SQLite.cs:304 [mono-rt] at SQLite.TableQuery`1..ctor (SQLite.SQLiteConnection) [0x00010] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Helpers\SQLite.cs:2473 [mono-rt] at SQLite.SQLiteConnection.Table<T> () [0x00001] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Helpers\SQLite.cs:768 [mono-rt] at Music.DataManager.DatabaseUpdates.GetPlaylist (int,string) [0x00027] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Helpers\DataManagerHelper.cs:288 [mono-rt] at Music.Music_SelectTheme/<>c__DisplayClass2.<OnCreateView>b__1 (object,System.EventArgs) [0x00001] in c:\Users\Exoskeletor\Documents\Projects\Music\Music\Music_SelectTheme.cs:77 [mono-rt] at Android.Views.View/IOnClickListenerImplementor.OnClick (Android.Views.View) [0x0000d] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.20-series/ba9bbbdd/source/monodroid/src/Mono.Android/platforms/android-15/src/generated/Android.Views.View.cs:1615 [mono-rt] at Android.Views.View/IOnClickListenerInvoker.n_OnClick_Landroid_view_View_ (intptr,intptr,intptr) [0x00011] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.20-series/ba9bbbdd/source/monodroid/src/Mono.Android/platforms/android-15/src/generated/Android.Views.View.cs:1582 [mono-rt] at (wrapper dynamic-method) object.a2a00f7c-dc24-4757-ba0d-9fa6ea56b30a (intptr,intptr,intptr) <IL 0x00017, 0x0001f> [mono-rt] at (wrapper native-to-managed) object.a2a00f7c-dc24-4757-ba0d-9fa6ea56b30a (intptr,intptr,intptr) <IL 0x00023, 0xffffffff> [mono-rt] [mono-rt] ================================================================= [mono-rt] Got a SIGSEGV while executing native code. This usually indicates [mono-rt] a fatal error in the mono runtime or one of the native libraries [mono-rt] used by your application. [mono-rt] ================================================================= [mono-rt] [libc] Fatal signal 11 (SIGSEGV) at 0xdeadbaad (code=1), thread 1385 (Music.Music) 

One Solution collect form web for “Unir tablas en SQLite.Net con LINQ en xamarin.android no es compatible”

SQLite no admite unirse a través de Linq por ahora por lo que sé. Tuve que usar la sintaxis de la consulta como este:

 var q = database.Query<MusicItems>( "select MI.Name, MI.ResId, MI.Tension from MusicItems MI" + " inner join MusicInThemes MT" + " on MI.ResId = MT.ResId where MT.ThemeId = ?", ThemeID).ToList(); return q.ConvertAll(x => new Playlist { Name = x.Name, ResId = x.ResId, LoopStart = x.LoopStart }); 
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