我有一些数据模型：
[DataContract(Name = "artist")]
public class artist : IEqualityComparer<artist>
{
[Key]
[XmlIgnore]
[DataMember]
public int ID { get; set; }
[DataMember]
[XmlElement(ElementName = "name")]
public string name { get; set; }
[DataMember]
[XmlElement(ElementName = "mbid", IsNullable = true)]
public string mbid { get; set; }
[DataMember]
[XmlElement(ElementName = "url")]
public string url { get; set; }
[XmlElement(ElementName = "image", IsNullable = true)]
public List<string> image { get; set; }
[DataMember(IsRequired=false)]
[XmlElement(ElementName = "stats", IsNullable = true)]
public stats stats { get; set; }
public double? match { get; set; }
public List<tag> tags { get; set; }
[XmlElement(ElementName = "similar")]
[DataMember(Name = "similar")]
public List<artist> similar { get; set; }
[DataMember]
[XmlElement(ElementName = "bio", IsNullable = true)]
public wiki bio { get; set; }
public bool Equals(artist x, artist y)
{
return x.name == y.name;
}
public int GetHashCode(artist obj)
{
return obj.name.GetHashCode();
}
}
和一个复杂的类型：
[DataContract]
[ComplexType]
[XmlRoot(ElementName = "streamable", IsNullable = true)]
public class stats
{
[DataMember(IsRequired = false)]
public int listeners { get; set; }
[DataMember(IsRequired = false)]
public int playcount { get; set; }
}
和数据库收录：
[Table("CachedArtistInfo")]
public class MusicArtists
{
[Key]
public string artistName { get; set; }
public artist artistInfo { get; set; }
private DateTime _added = default(DateTime);
[DataMember(IsRequired = true)]
[Timestamp]
public DateTime added
{
get
{
return (_added == default(DateTime)) ? DateTime.Now : _added;
}
set { _added = value; }
}
}
最后一步：
foreach (artist a in id)
{
df.CachedArtists.Add(new MusicArtists() { artistName = a.name, artistInfo = a });
df.SaveChanges();
}
错误：ExceptionType“System.Data.Entity.Infrastructure.DbUpdateException”“不可为空成员的空值。成员：'stats'。” 变量已完全填充，其中包含对象统计信息。怎么了？
