我有一个新的Xamarin Forms应用程序,我正在尝试为ORM使用Sqlite-net和Sqlite-net扩展。我跟着This guide创建了n:n。这是我的两个对象,以及它们的中间对象:
国家
using Sqlite;
using SQLiteNetExtensions.Attributes;
using System.Collections.Generic;
namespace MyNamespace.Models
{
public class Nation
{
[PrimaryKey, AutoIncrement]
public int Id { get; set; }
public string Name { get; set; }
public string Adjective { get; set; }
public double Frequency { get; set; }
[ManyToMany(typeof(NationFirstName))]
public List<FirstName> FirstNames { get; set; }
}
}
姓
using SQLite;
using SQLiteNetExtensions.Attributes;
using System.Collections.Generic;
namespace MyNamespace.Models
{
public class FirstName
{
[PrimaryKey, AutoIncrement]
public int Id { get; set; }
public string Name { get; set; }
[ManyToMany(typeof(NationFirstName))]
public List<Nation> Nations { get; set; }
}
}
NationFirstName
using SQLite;
using SQLiteNetExtensions.Attributes;
namespace OffseasonGM.Models
{
public class NationFirstName
{
[ForeignKey(typeof(Nation))]
public int NationId { get; set; }
[ForeignKey(typeof(FirstName))]
public int FirstNameId { get; set; }
}
}
所以,在我的应用程序的起点App.xaml.cs中,我尝试首先创建NationFirstNameRepository,它运行良好。接下来,我尝试创建NationRepository,在构造函数中我得到一个异常。在CreateTable()行:
[ERROR] FATAL UNHANDLED EXCEPTION: System.NotSupportedException: Don't know about System.Collections.Generic.List`1[OffseasonGM.Models.FirstName]
NationRepository.cs
using MyNamespace.Models;
using SQLite;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;
namespace MyNamespace.Assets.Repositories
{
public class NationReposistory
{
SQLiteConnection connection;
public NationReposistory(string dbPath)
{
connection = new SQLiteConnection(dbPath);
var entriesCreatedCount = connection.CreateTable<Nation>();
if (entriesCreatedCount < 1)
{
SeedNations();
}
}
public void AddNewNation(string name, string adjective, double frequency)
{
try
{
connection.Insert(new Nation { Name = name, Adjective = adjective, Frequency = frequency });
}
catch (Exception e)
{
//TODO: Error handling.
}
}
public List<Nation> GetAllNations()
{
return connection.Table<Nation>().ToList();
}
private void SeedNations()
{
var assembly = typeof(MainPage).GetTypeInfo().Assembly;
var stream = assembly.GetManifestResourceStream("MyNamespace.Nations.txt");
using (var reader = new StreamReader(stream))
{
var line = reader.ReadLine().Split('|');
var name = line[0];
var adjective = line[1];
var frequency = double.Parse(line[2]);
AddNewNation(name, adjective, frequency);
}
}
}
}
我是在做一些乱序,还是完全忘了什么?非常感谢任何建议。
答案 0 :(得分:0)
这里的错误相同。 我卸载包含PCL的所有nugets,删除bin和obj文件夹,清理解决方案,添加SQLiteNetExtensions 1.3.0和SQLite.Net-PCL 3.1.1 nugets,再次清理并重建。为我工作,我想这些软件包的新版本之间存在一些不兼容性。
希望这有帮助!