CoolStorage在Windows Phone 7上的映射问题

Question

我正在使用Vici.CoolStorage在Windows Phone 7应用程序中访问SQLite数据库。在这一行代码中，我遇到了一个空引用异常：

 CSList<Regimen> regimens = Regimen.List();

我在我的数据库中有两个表：

CREATE TABLE Regimen (
    ID INTEGER PRIMARY KEY,
    Name TEXT(50) NOT NULL
);

CREATE TABLE WorkoutDay (
    ID INTEGER PRIMARY KEY,
    DayNumber INTEGER NOT NULL,
    RegimenID INTEGER REFERENCES Regimen(ID)
);

相关模型的映射如下：

using Vici.CoolStorage;

namespace MyApp.Core.Domain
{
    [MapTo("Regimen")]
    public class Regimen : CSObject<Regimen,int>
    {  
        public int ID
        {
            get { return (int)GetField("ID"); }
            set { SetField("ID", value); }
        }
        public string Name
        {
            get { return (string)GetField("Name"); }
            set { SetField("Name", value); }
        }

        [OneToMany(LocalKey = "ID", ForeignKey = "RegimenID")]
        public CSList WorkoutDays
        {
            get { return (CSList)GetField("WorkoutDays"); }
        }
    }
}

using Vici.CoolStorage;

namespace MyApp.Core.Domain
{
    [MapTo("WorkoutDay")]
    public class WorkoutDay : CSObject<WorkoutDay,int>
    {
        public int ID
        {
            get { return (int)GetField("ID"); }
            set { SetField("ID", value); }
        }
        public int DayNumber
        {
            get { return (int)GetField("DayNumber"); }
            set { SetField("DayNumber", value); }
        }

        [ManyToOne(LocalKey="RegimenID", ForeignKey="ID")]
        public Regimen Regimen
        {
            get { return (Regimen)GetField("Regimen"); }
            set { SetField("Regimen", value);}
        }
    }
}

如果我在Regimen模型中注释掉OneToMany关系，它就能正常工作。我无法弄清楚我的映射有什么问题。

- JeffCren

Answer 1

在你的Regimen类中，返回类型不应该是CSList，而应该是CSList<WorkoutDay>，请进行以下更改：

    [OneToMany(LocalKey = "ID", ForeignKey = "RegimenID")]
    public CSList WorkoutDays
    {
        get { return (CSList)GetField("WorkoutDays"); }
    }

变成这样：

    [OneToMany(LocalKey = "ID", ForeignKey = "RegimenID")]
    public CSList<WorkoutDay> WorkoutDays
    {
        get { return (CSList<WorkoutDay>)GetField("WorkoutDays"); }
    }

请参考此处文档（位于一对多关系章节下的最后一段）：http://viciproject.com/wiki/Projects/CoolStorage/Doc/UserGuide/Mapping

- theChrisKent