用于建模的非原始数据类型？

Question

public class Song
    {
        public int SongID { get; set; }
        public string URL { get; set; }
        public virtual TagLib.Tag SongInfo { get; set; }
    }

我想在Song实体中使用“TagLib.Tag”数据类型。 当我尝试启用迁移时，我得到：

One or more validation errors were detected during model generation:

\tSystem.Data.Entity.Edm.EdmEntityType: : EntityType 'XmpNode' has no key defined. Define the key for this EntityType.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_Exif_Source' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_Exif_Target' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'XmpTag_NodeTree_Source' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_Xmp_Source' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_Xmp_Target' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_OtherTags_Source' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_OtherTags_Target' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_AllTags_Source' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: : The referenced EntitySet 'Tags' for End 'CombinedImageTag_AllTags_Target' could not be found in the containing EntityContainer.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'XmpNodes' is based on type 'XmpNode' that has no keys defined.
\tSystem.Data.Entity.Edm.EdmEntitySet: EntityType: EntitySet 'Tags' is based on type 'Tag' that has no keys defined.

如何在模型中使用外部复杂数据类型？

Answer 1

我看到有关Tag实体类的错误，您没有为此Key属性定义。

也许您的代码如下：

public class Tag
{
    public string TagName{get; set;}
    // other fields
}

您必须按如下方式进行更改：

public class Tag
{
    [Key]
    public int TagId{get; set;}
    public string TagName{get; set;}
    // other fields
}