EntityFramework 4.0:InvalidOperationExeception:违反了多重性约束

Question

我们最近将我们的软件升级到.NET 4.0和EF 4.0(没有自我跟踪实体)(以前的.NET 3.5 SP1).现在,在以前的工作代码中引发了一个新的异常,我们不明白.

我们有一个名为Resident的实体,另一个名为ResidentExtension的实体,它将已经很大的Resident实体扩展为1到(0/1)的关系.以下c#代码在我们的应用程序中生成一个新实体:

Residents resident = new Residents()
   {
       IsNewResident = true,
       ResidentImage = Settings.Default.ResidentCardDefaultMaleImage,
       IsActive = true,
       ResidentCanBeDeleted = true,
       ResidentExtensions = new ResidentExtensions(),
       ResidentMasterDataState = EvoState.Error,
       ResidentBasicDataState = EvoState.Error,
       ResidentBenefactorsDataState = EvoState.Error,
   };

在此声明后直接引发以下异常:

违反了多重约束.关系VOCURA.EntityDataModels.EvocuraCarehomeManagementEntityModel.FK_ResidentExtensions_Residents'的角色'ResidentExtensions'具有多重性1或0..1.

它出现在生成的代码的setter中:

    [XmlIgnoreAttribute()]
    [SoapIgnoreAttribute()]
    [DataMemberAttribute()]
    [EdmRelationshipNavigationPropertyAttribute("EVOCURA.EntityDataModels.EvocuraCarehomeManagementEntityModel", "FK_ResidentExtensions_Residents", "ResidentExtensions")]
    public ResidentExtensions ResidentExtensions
    {
        get
        {
            return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<ResidentExtensions>("EVOCURA.EntityDataModels.EvocuraCarehomeManagementEntityModel.FK_ResidentExtensions_Residents", "ResidentExtensions").Value;
        }
        set
        {
            ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<ResidentExtensions>("EVOCURA.EntityDataModels.EvocuraCarehomeManagementEntityModel.FK_ResidentExtensions_Residents", "ResidentExtensions").Value = value;
        }
    }

我发现的唯一解决方案是首先提交没有扩展名的Resident实体,然后创建ResidentExtension并设置外键(ResidentID)并将其添加到上下文并再次提交.但这不是它以前的工作方式.

有谁知道如何让这项工作再次成为旧的方式？

Answer 1

ResidentExtensions = new ResidentExtensions(),

我认为这条线根本不需要。您正在创建一个新的 residentextensions 对象，该对象没有任何主键并且数据库中不存在。当上下文尝试保存 residentextensions 时，它无法保存，因为没有设置任何属性，这可能会导致数据库中出现一些与不可为空字段相关的异常。我认为你需要做的是以下事情；

Residents resident = new Residents()
   {
       IsNewResident = true,
       ResidentImage = Settings.Default.ResidentCardDefaultMaleImage,
       IsActive = true,
       ResidentCanBeDeleted = true,
       ResidentMasterDataState = EvoState.Error,
       ResidentBasicDataState = EvoState.Error,
       ResidentBenefactorsDataState = EvoState.Error,
   };
//Now you need to either initialize a residentextextensions entity
// with proper values, or just do not relate it with the resident entity.
ResidentExtensions temp = new ResidentExtensions();
temp.PropertyA = 3;
//etc.
resident.ResidentExtensions = temp;

综上所述，由于 Resident 实体与 ResidentExtensions 具有 1 - 0,1 关系；如果右边是0；只需将 ResidentExtensions 属性保留为空即可；否则初始化适当的 ResidentExtensions 对象并设置相关属性。