[英]Entity Framework null pointer reference exception
我有兩個表之間的關系
第一表: 用戶
Id | Name |
第二張表: 套餐
Id | UserSenderId | UserReceiverId
我將Entity Framework與.Net Framework 3.5結合使用,但問題是Entity Framework正在創建兩個引用UserReference1
和UserReference
但UserReference1
始終為null。 如果我不包括這樣的User
表:
db.Packages.Include("User")
那么UserReference
也為null。
我真的沒有這個問題的主意,使用多個外鍵指向同一主鍵是否存在問題?
編輯1:
在用戶參考Package
部分類:
[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);
}
}
}
任何幫助表示贊賞,謝謝!
嘗試db.Packages.Include("User").Include("User1")
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