实体框架 - 如何使用实体关联？

Question

当我的数据库中的表具有PK/FK关系(int)时,当它们由实体框架设计器建模时,一切都应该如此.我可以编写下面的代码,一切似乎都可以正常工作但是当我运行代码时,我在项目上得到一个错误.Status.StatusName说Object引用没有设置为对象的实例.我想我的印象是,当您填充父实体时,框架会填充关联的实体.

    Dim db As New MyDbModel.MyDbEntities()

    Dim project As MyDbModel.Project = (From p In db.Project Where p.ProjectID = 1).First

    Response.Write(project.ProjectName)        
    Response.Write(project.Status.StatusName)

Answer 1

尝试使用Include(RelationshipName)

Dim db As New MyDbModel.MyDbEntities()    
Dim project As MyDbModel.Project = (From p In db.Project.Include("Status") Where p.ProjectID = 1).First    
Response.Write(project.ProjectName)            
Response.Write(project.Status.StatusName)