违反了多重约束。关系'*'的作用'*'具有多重性1或0..1。

问题描述

大家好，

我正在使用实体框架4的自我追踪实体！

更新外键并保存时出现以下错误。

用户代码未处理System.InvalidOperationException
  Message =违反了Multiplicity约束。 "PI.Entities.DesignationEmployee"关系的"指定"角色具有多重性1或0..1。 源= System.Data.Entity的
 堆栈跟踪：
       at System.Data.Objects.DataClasses.EntityReference`1.VerifyMultiplicityConstraintsForAdd（Boolean applyConstraints）
      在System.Data.Objects.DataClasses.RelatedEnd.Add（IEntityWrapper wrappedTarget，布尔applyConstraints，布尔addRelationshipAsUnchanged，布尔relationshipAlreadyExists，布尔allowModifyingOtherEndOfRelationship，布尔forceForeignKeyChanges）
      在System.Data.Objects.ObjectStateManager.CreateRelationship（EntityEntry targetEntry，RelatedEnd relatedEnd，RelationshipWrapper relationshipWrapper，EntityState requestedState）
      在System.Data.Objects.ObjectStateManager.ChangeRelationshipState（EntityEntry sourceEntry，EntityEntry targetEntry，RelatedEnd relatedEnd，EntityState relationshipState）
      在System.Data.Objects.ObjectStateManager.ChangeRelationshipState（Object sourceEntity，Object targetEntity，String relationshipName，String targetRoleName，EntityState relationshipState）
      在PI.Entities.ObjectContextExtensions.ApplyChanges [TEntity]（ObjectContext context，String entitySetName，TEntity entity）

这在执行以下代码的方法ApplyChanges中发生，

;               //将所有未触动的关系更改回未更改状态
                foreach（allRelationships中的var关系）
                {
                    context.ObjectStateManager.ChangeRelationshipState（
                         relationship.End0，                         relationship.End1，
                         relationship.AssociationSet.ElementType.FullName，
                         relationship.AssociationEndMembers [1] .name和
       &NBSP ;                EntityState.Unchanged）;
             & NBSP;   }

请让我知道为什么会出现这种错误？

感谢&问候，
Kannan

Hi All,

I'm using Self-Tracking Entities of Entity Framework 4 !

I'm getting the following error when updating a foreign key and saving.

System.InvalidOperationException was unhandled by user code
  Message=Multiplicity constraint violated. The role 'Designation' of the relationship 'PI.Entities.DesignationEmployee' has multiplicity 1 or 0..1.
  Source=System.Data.Entity
  StackTrace:
       at System.Data.Objects.DataClasses.EntityReference`1.VerifyMultiplicityConstraintsForAdd(Boolean applyConstraints)
       at System.Data.Objects.DataClasses.RelatedEnd.Add(IEntityWrapper wrappedTarget, Boolean applyConstraints, Boolean addRelationshipAsUnchanged, Boolean relationshipAlreadyExists, Boolean allowModifyingOtherEndOfRelationship, Boolean forceForeignKeyChanges)
       at System.Data.Objects.ObjectStateManager.CreateRelationship(EntityEntry targetEntry, RelatedEnd relatedEnd, RelationshipWrapper relationshipWrapper, EntityState requestedState)
       at System.Data.Objects.ObjectStateManager.ChangeRelationshipState(EntityEntry sourceEntry, EntityEntry targetEntry, RelatedEnd relatedEnd, EntityState relationshipState)
       at System.Data.Objects.ObjectStateManager.ChangeRelationshipState(Object sourceEntity, Object targetEntity, String relationshipName, String targetRoleName, EntityState relationshipState)
       at PI.Entities.ObjectContextExtensions.ApplyChanges[TEntity](ObjectContext context, String entitySetName, TEntity entity)

This happens in the method ApplyChanges when executing the following code,

                // Change all the untouched relationship back to unchanged state
                foreach (var relationship in allRelationships)
                {
                    context.ObjectStateManager.ChangeRelationshipState(
                        relationship.End0,
                        relationship.End1,
                        relationship.AssociationSet.ElementType.FullName,
                        relationship.AssociationEndMembers[1].Name,
                        EntityState.Unchanged);
                }

Please let me know why this error occurs ?

Thanks & Regards,
Kannan

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