Sqlite-net: Default constructor not found for type System.String

[santiagohdzb]

I'm receiving an error in this line:

``` C#
// this works
return db.Table().ToList().Select(p => p.Key).ToList();

// this doesn't
return db.Table().Select(p => p.Key).ToList();

This part of my code:

``` C#
public class Preferences
{
    class Preference
    {
        [PrimaryKey]
        public string Key { get; set; }
        public string Value { get; set; }

        public Preference(){}
        public Preference(string key, string value) {
            Key = key;
            Value = value;
        }
    }

    static bool init;
    static SQLiteConnection DBConnection {
        get { return InitDB(CreateConnection("Preferences")); }
    }

    static SQLiteConnection CreateConnection(string dbname) {
        var nameFileDB = dbname + "_db";
        var docsFolder = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments);
        var pathToDB = Path.Combine(docsFolder, nameFileDB);

        return new SQLiteConnection(pathToDB);
    }

    static SQLiteConnection InitDB(SQLiteConnection conn) {
        if (!init) {
            conn.CreateTable<Preference>();
            init = true;
        }

        return conn;
    }

    public static List<string> AllKeys() {
        using (var db = DBConnection) {
            // this works
            // return db.Table<Preference>().ToList().Select(p => p.Key).ToList();

            // this doesn't
            return db.Table<Preference>().Select(p => p.Key).ToList();
        }
    }
}

This is part of my class, and I'm getting the error after I insert some values on the table and then call Preferences.AllKeys() function

StackTrace:

[MonoDroid] UNHANDLED EXCEPTION:
[MonoDroid] System.MissingMethodException: Default constructor not found for type System.String
[MonoDroid]   at System.RuntimeType.CreateInstanceMono (Boolean nonPublic) [0x00085] in /Users/builder/data/lanes/2512/d3008455/source/mono/mcs/class/corlib/ReferenceSources/RuntimeType.cs:105 
[MonoDroid]   at System.RuntimeType.CreateInstanceSlow (Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, System.Threading.StackCrawlMark& stackMark) [0x0001a] in /Users/builder/data/lanes/2512/d3008455/source/mono/mcs/class/corlib/ReferenceSources/RuntimeType.cs:87 
[MonoDroid]   at System.RuntimeType.CreateInstanceDefaultCtor (Boolean publicOnly, Boolean skipCheckThis, Boolean fillCache, System.Threading.StackCrawlMark& stackMark) [0x0002a] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/mscorlib/system/rttype.cs:5734 
[MonoDroid]   at System.Activator.CreateInstance (System.Type type, Boolean nonPublic) [0x00040] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/mscorlib/system/activator.cs:214 
[MonoDroid]   at System.Activator.CreateInstance (System.Type type) [0x00000] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/mscorlib/system/activator.cs:147 
[MonoDroid]   at SQLite.SQLiteCommand+<ExecuteDeferredQuery>d__0`1[T].MoveNext () [0x000d3] in g:\Project1\Models\Database\SQLite.cs:2203 
[MonoDroid]   at System.Collections.Generic.List`1[T]..ctor (IEnumerable`1 collection) [0x0008b] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/mscorlib/system/collections/generic/list.cs:105 
[MonoDroid]   at System.Linq.Enumerable.ToList[TSource] (IEnumerable`1 source) [0x00011] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/System.Core/System/Linq/Enumerable.cs:835 
[MonoDroid]   at SQLite.SQLiteCommand.ExecuteQuery[T] () [0x00001] in g:\Project1\Models\Database\SQLite.cs:2161 
[MonoDroid]   at SQLite.TableQuery`1[T].GetEnumerator () [0x0000b] in g:\Project1\Models\Database\SQLite.cs:2992 
[MonoDroid]   at System.Collections.Generic.List`1[T]..ctor (IEnumerable`1 collection) [0x00073] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/mscorlib/system/collections/generic/list.cs:104 
[MonoDroid]   at System.Linq.Enumerable.ToList[TSource] (IEnumerable`1 source) [0x00011] in /Users/builder/data/lanes/2512/d3008455/source/mono/external/referencesource/System.Core/System/Linq/Enumerable.cs:835 
[MonoDroid]   at SQLite.Preferences.Preferences.AllKeys () [0x00008] in g:\Project1\Preferences.cs:27 
[MonoDroid]   at Android.Support.V4.App.FragmentActivity.n_OnCreate_Landroid_os_Bundle_ (IntPtr jnienv, IntPtr native__this, IntPtr native_savedInstanceState) [0x00011] in <filename unknown>:0 
[MonoDroid]   at (wrapper dynamic-method) System.Object:d8fe4472-f53e-45af-8812-e33bedf2f3cf (intptr,intptr,intptr)
[art] JNI RegisterNativeMethods: attempt to register 0 native methods for md52ce486a14f4bcd95899665e9d932190b.JavaProxyThrowable

Target OS: Android
Xamarin Studio: Version 5.10.1 (build 6)
Runtime:
Microsoft .NET 4.0.30319.42000
GTK+ 2.24.23 (MS-Windows theme)
GTK# 2.12.30
Xamarin.Android: Version: 6.0.0 (Business Edition)
SDK Tools Version: 24.4.1
SDK Platform Tools Version: 23.1
SDK Build Tools Version: 23.0.1
java version "1.7.0_79"
Java(TM) SE Runtime Environment (build 1.7.0_79-b15)
Java HotSpot(TM) 64-Bit Server VM (build 24.79-b02, mixed mode)
Dev OS: Windows 8.1 (64-bit)

[tarrball]

Same issue with anonymous object. This doesn't work:

db.Table<Video>().Where(...).Select(v => new { Summary = v.Summary, Id = v.Id }).ToList();

This works:

db.Table<Video>().Where(...).ToList().Select(v => new { Summary = v.Summary, Id = v.Id }).ToList();

[CGollhardt]

Any news? It raised an Stack Overflow question:

https://stackoverflow.com/questions/44350374/is-performing-tolist-more-than-once-is-a-bad-idea

[praeclarum]

This will be fixed in the 1.5 series.

Fixed in: https://github.com/praeclarum/sqlite-net/commit/2c5f1e1337fddd9f1ae62e3af9828693f2c21d89