/// <summary>
/// 按实体属性更新上下文中指定实体的状态
/// </summary>
/// <typeparam name="TEntity">实体类型</typeparam>
/// <typeparam name="TKey">实体主键类型</typeparam>
/// <param name="dbContext">上下文对象</param>
/// <param name="propertyExpression">实体属性表达式，提供要更新的实体属性</param>
/// <param name="entities">附带新值的实体对象，必须包含主键</param>
public static void Update <TEntity, TKey>(this DbContext dbContext,
Expression <Func <TEntity, object> > propertyExpression,
params TEntity[] entities)
where TEntity : EntityBase <TKey>
{
propertyExpression.CheckNotNull("propertyExpression");
entities.CheckNotNull("entities");
ReadOnlyCollection <MemberInfo> memberInfos = ((dynamic)propertyExpression.Body).Members;
foreach (TEntity entity in entities)
{
DbSet <TEntity> dbSet = dbContext.Set <TEntity>();
try
{
DbEntityEntry <TEntity> entry = dbContext.Entry(entity);
entry.State = EntityState.Unchanged;
foreach (MemberInfo memberInfo in memberInfos)
{
entry.Property(memberInfo.Name).IsModified = true;
}
}
catch (InvalidOperationException)
{
TEntity originalEntity = dbSet.Local.Single(m => Equals(m.Id, entity.Id));
ObjectContext objectContext = ((IObjectContextAdapter)dbContext).ObjectContext;
ObjectStateEntry objectEntry = objectContext.ObjectStateManager.GetObjectStateEntry(originalEntity);
objectEntry.ApplyCurrentValues(entity);
objectEntry.ChangeState(EntityState.Unchanged);
foreach (MemberInfo memberInfo in memberInfos)
{
objectEntry.SetModifiedProperty(memberInfo.Name);
}
}
}
}
public void ChangeState(EntityState state)
{
_stateEntry.ChangeState(state);
}
