[英]Entity Framework null pointer reference exception
I have a relationship between two tables 我有两个表之间的关系
First table: User 第一表: 用户
Id | Name |
Second table: Package 第二张表: 套餐
Id | UserSenderId | UserReceiverId
I use Entity Framework with .Net Framework 3.5 and the problem I have is that Entity Framework is creating two references UserReference1
and UserReference
but UserReference1
is always null. 我将Entity Framework与.Net Framework 3.5结合使用,但问题是Entity Framework正在创建两个引用UserReference1
和UserReference
但UserReference1
始终为null。 If I do not include the User
table like this: 如果我不包括这样的User
表:
db.Packages.Include("User")
then UserReference
is also null. 那么UserReference
也为null。
I really run out of ideas with this problem, is there an issue using multiple foreign keys pointing to the same primary key? 我真的没有这个问题的主意,使用多个外键指向同一主键是否存在问题?
EDIT 1: 编辑1:
The user reference in Package
partial class: 在用户参考Package
部分类:
[global::System.Data.Objects.DataClasses.EdmRelationshipNavigationPropertyAttribute("Tema4Model", "FK_Package_User_Receiver", "User")]
[global::System.CodeDom.Compiler.GeneratedCode("System.Data.Entity.Design.EntityClassGenerator", "4.0.0.0")]
[global::System.Xml.Serialization.XmlIgnoreAttribute()]
[global::System.Xml.Serialization.SoapIgnoreAttribute()]
[global::System.Runtime.Serialization.DataMemberAttribute()]
public User User
{
get
{
return ((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Receiver", "User").Value;
}
set
{
((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Receiver", "User").Value = value;
}
}
/// <summary>
/// There are no comments for User in the schema.
/// </summary>
[global::System.ComponentModel.BrowsableAttribute(false)]
[global::System.CodeDom.Compiler.GeneratedCode("System.Data.Entity.Design.EntityClassGenerator", "4.0.0.0")]
[global::System.Runtime.Serialization.DataMemberAttribute()]
public global::System.Data.Objects.DataClasses.EntityReference<User> UserReference
{
get
{
return ((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Receiver", "User");
}
set
{
if ((value != null))
{
((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.InitializeRelatedReference<User>("Tema4Model.FK_Package_User_Receiver", "User", value);
}
}
}
/// <summary>
/// There are no comments for User1 in the schema.
/// </summary>
[global::System.Data.Objects.DataClasses.EdmRelationshipNavigationPropertyAttribute("Tema4Model", "FK_Package_User_Sender", "User")]
[global::System.CodeDom.Compiler.GeneratedCode("System.Data.Entity.Design.EntityClassGenerator", "4.0.0.0")]
[global::System.Xml.Serialization.XmlIgnoreAttribute()]
[global::System.Xml.Serialization.SoapIgnoreAttribute()]
[global::System.Runtime.Serialization.DataMemberAttribute()]
public User User1
{
get
{
return ((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Sender", "User").Value;
}
set
{
((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Sender", "User").Value = value;
}
}
/// <summary>
/// There are no comments for User1 in the schema.
/// </summary>
[global::System.ComponentModel.BrowsableAttribute(false)]
[global::System.CodeDom.Compiler.GeneratedCode("System.Data.Entity.Design.EntityClassGenerator", "4.0.0.0")]
[global::System.Runtime.Serialization.DataMemberAttribute()]
public global::System.Data.Objects.DataClasses.EntityReference<User> User1Reference
{
get
{
return ((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.GetRelatedReference<User>("Tema4Model.FK_Package_User_Sender", "User");
}
set
{
if ((value != null))
{
((global::System.Data.Objects.DataClasses.IEntityWithRelationships)(this)).RelationshipManager.InitializeRelatedReference<User>("Tema4Model.FK_Package_User_Sender", "User", value);
}
}
}
Any help is appreciated, thanks! 任何帮助表示赞赏,谢谢!
尝试db.Packages.Include("User").Include("User1")
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