C# Windows Phone 8现有数据库InvalidCastException:指定的强制转换无效
我正在使用预填充的数据库。当应用程序启动时,我将数据库从资产复制到isostore。 实体:C# Windows Phone 8现有数据库InvalidCastException:指定的强制转换无效,c#,windows-phone,sql-server-ce,C#,Windows Phone,Sql Server Ce,我正在使用预填充的数据库。当应用程序启动时,我将数据库从资产复制到isostore。 实体: [Table(Name = "NAMES")] public class NameItem: INotifyPropertyChanged, INotifyPropertyChanging { public event PropertyChangedEventHandler PropertyChanged; public event PropertyChangingEventHandle
[Table(Name = "NAMES")]
public class NameItem: INotifyPropertyChanged,
INotifyPropertyChanging {
public event PropertyChangedEventHandler PropertyChanged;
public event PropertyChangingEventHandler PropertyChanging;
private string _nameString;
private int _id;
[Column(IsPrimaryKey = true, IsDbGenerated = true, Name = "_id")]
public int NameId {
get {
return _id;
}
set {
if (value != _id) {
OnPropertyChanging("NameId");
_id = value;
OnPropertyChanged("NameId");
}
}
}
[Column(IsPrimaryKey = false, Name = "NAME_TEXT")]
public String NameString {
get {
return _nameString;
}
set {
if (_nameString != value) {
OnPropertyChanging("NameString");
_nameString = value;
OnPropertyChanged("NameString");
}
}
}
}
在这里,我尝试从db读取数据:
using(var db = new MyDataContext("isostore:/Database/ff.sdf")) {
var allNameItems = db.NameItems.ToArray(); // exception on this line
try {
MessageBox.Show(allNameItems[0].NameString);
} catch (Exception ex) {
MessageBox.Show(ex.Message);
}
}
有了这段代码,我得到了InvalidCastException,但是db.NameItems.Count起作用。好的,我读了这段代码,发现了问题,我在db中的id字段是BigInt,在Entity中是int。我把它改为long,它就起作用了