SQLite3 Connection Causes Confusing Compile Error

Question

I am attempting to compile my Xamarin project and I am getting a compiler error that I dont understand. What does the following error mean and how can i fix this?

Data\SQLiteClient.cs(4,4): Error CS0012: The type 'System.Threading.Tasks.TaskScheduler' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Threading.Tasks, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. (CS0012) (DtoToVm.Droid)

Relevant information:

Xamarin Forms blank project PCL
Project set to .NET 4.5 or later
Profile: PCL 4.5 - Profile78

Alot of references are not happy but I haven't manually setup or editted these. Maybe a nuget package conflict?

using Xamarin.Forms;  
using DtoToVm.Droid.Data;

[assembly: Dependency (typeof(SQLiteClient))]
namespace DtoToVm.Droid.Data  
{
using System;
using DtoToVm.Data;
using SQLite.Net.Async;
using System.IO;
using SQLite.Net.Platform.XamarinAndroid;
using SQLite.Net;

public class SQLiteClient : ISQLite
{
    public SQLiteAsyncConnection GetConnection ()
    {
        var sqliteFilename = "Conferences.db3";
        var documentsPath = Environment.GetFolderPath (Environment.SpecialFolder.Personal);

        var path = Path.Combine (documentsPath, sqliteFilename);

        var platform = new SQLitePlatformAndroid ();

        var connectionWithLock = new SQLiteConnectionWithLock (
            platform,
            new SQLiteConnectionString (path, true));


        // The below line causes the compile error
        var connection = new SQLiteAsyncConnection (() => connectionWithLock);

        return connection;
    }
}
}

Edit: According to this thread I shd change the profile to 7. I've done this and it got rid of all errors but produced a new one:

DtoToVm\packages\Microsoft.Net.Http.2.2.29\lib\portable-net40+sl4+win8+wp71+wpa81\System.Net.Http.dll: Error CS1703: An assembly with the same identity 'System.Net.Http, Version=1.5.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' has already been imported. Try removing one of the duplicate references. (CS1703) (DtoToVm)

What file could this duplicate reference be in?

Have you tried adding the assembly "System.Threading.Tasks.TaskScheduler" to your project references? — helb
Pretty straight forward - it says in the exception - "add a reference to assembly 'System.Threading.Tasks'" to your project — Nissim
There is a SQLite PCL NuGet that may save you a lot of trouble - nuget.org/packages/SQLite.Net-PCL — Jason

Ibrahim Abdelkareem Ibrahim Abdelkareem · Accepted Answer · 2015-08-13T12:49:40

I don't really know if System.Threading.Tasks namespace exists in Xamarin or not, If it's exists then reference it, If not then use the regular SqliteConnection and don't use Async one.

SQLite3 Connection Causes Confusing Compile Error

1 Answers