我遇到了上述错误，不知道该怎么办。
您可以假设表已正确设置。这是问题代码：
var setting = _context.Settings.FirstOrDefault();
ICollection<PD_Datafile> PD_Datafiles = new Collection<PD_Datafile>();
for (int i = 0; i < numfiles; i++)
{
DAT_FILE PD_Datafile = ParseFileName(files[i].Name, filepath);
string databodystr = Encoding.Default.GetString(PD_Datafile.SensorData.DataBody);
PD_Datafiles.Add(new PD_Datafile() { DataId = i, FullName = files[i].Name, DataBody = databodystr });
}
setting.PD_Datafiles = PD_Datafiles;
ICollection<Alarm> alarms = new Collection<Alarm>();
alarms.Add(new Alarm() { AlarmId = 0, DateOccurred = 20210120, EquipmentType = "GISPD", FaultType = "PD Happening", Sensor = null, Details = "None" });
alarms.Add(new Alarm() { AlarmId = 1, DateOccurred = 20210121, EquipmentType = "CBCM", FaultType = "Warning", Sensor = null, Details = "None" });
alarms.Add(new Alarm() { AlarmId = 2, DateOccurred = 20210122, EquipmentType = "DGA", FaultType = "Danger", Sensor = null, Details = "None" });
alarms.Add(new Alarm() { AlarmId = 3, DateOccurred = 20210123, EquipmentType = "OLTC", FaultType = "Danger", Sensor = null, Details = "None" });
setting.Alarms = alarms;
_context.Settings.Update(setting);
_context.SaveChanges();
当 '_context' 保存更改时，它一直说“'数据库操作预计会影响 1 行，但实际上影响了 0 行。自从加载实体以来，数据可能已被修改或删除。”
经过一番谷歌搜索后，我也在每个表的主键上方添加了这个符号。
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
我想我以某种错误的方式添加了列表。
以下是我正在使用的表格：
namespace OA2.Model
{
public class Alarm
{
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int AlarmId { get; set; }
public string FaultType { get; set; }
public int DateOccurred { get; set; }
public Sensor Sensor { get; set; }
public string EquipmentType { get; set; }
public string Details { get; set; }
[ForeignKey("SettingId")]
public virtual Setting Setting { get; set; }
}
}
namespace OA2.Model
{
public partial class Setting
{
public Setting()
{
PD_Datafiles = new HashSet<PD_Datafile>();
SCBR_Datafiles = new HashSet<SCBR_Datafile>();
Alarms = new HashSet<Alarm>();
}
[Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int SettingId { get; set; }
public int EventAmpTh1 { get; set; }
public int EventPpsTh1 { get; set; }
public int EventAmpTh2 { get; set; }
public int EventPpsTh2 { get; set; }
public int PulselvlTh { get; set; }
public long TimePassed { get; set; }
public string FilePath { get; set; }
//public virtual PD_Datafile Data { get; set; }
public virtual ICollection<PD_Datafile> PD_Datafiles { get; set; }
public virtual ICollection<SCBR_Datafile> SCBR_Datafiles { get; set; }
public virtual ICollection<Alarm> Alarms { get; set; }
}
}
我在这里先向您的帮助表示感谢！
我认为警报桌上有问题。警报的 ID 是身份，因此您不需要添加警报 ID 第二件事是您同时修改两个表可能会出现异常。