我试图通过我得到的相关问题找到答案,但我没有看到与现在相同的情况。我是这个框架的初学者。问题是,在数据库中,TopicFeedbackType 总是被引用,但如果我附加实体,TopicNavigatedUrl 和 Product 总是插入事件。我究竟做错了什么?我将找到的实体附加到正确的实体集名称。实体被附加。我注意到在 p_TopicQuickFb 的一个属性被附加实体更新之前,它的 EntityKey 为空,但是当设置 currentNavUrl(例如)时,p_TopicQuickFb 的 EntityKey 不再为空。它的值为“EntitySet=TopicQuickFeedbacks”,但没有 id。我真的迷路了。
public void AddTopicQuickFeedback(TopicQuickFeedback p_TopicQuickFb, string p_SessionID)
{
TopicFeedbackType currentType = this.GetTopicFeedbackType(p_TopicQuickFb.TopicFeedbackType.FeedbackType);
bool currentTypeAttached = false;
TopicNavigatedUrl currentNavUrl = this.GetTopicNavigatedUrl(p_TopicQuickFb.TopicNavigatedUrl.Url);
bool currentNavUrlAttached = false;
Product currentProduct = this.GetProduct(p_TopicQuickFb.Product.Name, p_TopicQuickFb.Product.MajorVersion, p_TopicQuickFb.Product.MinorVersion);
bool currentProductAttached = false;
using (COHFeedbackEntities context = GetObjectContext())
{
TopicFeedback tf = GetTopicFeedback(p_SessionID, context);
if (tf != null)
{
if (currentType != null)
{
p_TopicQuickFb.TopicFeedbackType = null;
context.AttachToOrGet<TopicFeedbackType>("TopicFeedbackTypes", ref currentType);
currentTypeAttached = true;
p_TopicQuickFb.TopicFeedbackType = currentType;
}
if (currentNavUrl != null)
{
p_TopicQuickFb.TopicNavigatedUrl = null;
context.AttachToOrGet<TopicNavigatedUrl>("TopicNavigatedUrls", ref currentNavUrl);
currentNavUrlAttached = true;
p_TopicQuickFb.TopicNavigatedUrl = currentNavUrl;
}
if (currentProduct != null)
{
p_TopicQuickFb.Product = null;
context.AttachToOrGet<Product>("Products", ref currentProduct);
currentProductAttached = true;
p_TopicQuickFb.Product = currentProduct;
}
tf.TopicQuickFeedbacks.Add(p_TopicQuickFb);
context.SaveChanges();
context.Detach(tf);
if (currentNavUrlAttached)
{
context.TopicNavigatedUrls.Detach(currentNavUrl);
}
if (currentProductAttached)
{
context.Products.Detach(currentProduct);
}
if (currentTypeAttached)
{
context.TopicFeedbackTypes.Detach(currentType);
}
}
}
}
我在这篇文章中找到了方法:Is is possible to check if an object is already attach to a data context in Entity Framework?
public static void AttachToOrGet<T>(this System.Data.Objects.ObjectContext context, string entitySetName, ref T entity)
where T : IEntityWithKey
{
System.Data.Objects.ObjectStateEntry entry;
// Track whether we need to perform an attach
bool attach = false;
if (
context.ObjectStateManager.TryGetObjectStateEntry
(
context.CreateEntityKey(entitySetName, entity),
out entry
)
)
{
// Re-attach if necessary
attach = entry.State == EntityState.Detached;
// Get the discovered entity to the ref
entity = (T)entry.Entity;
}
else
{
// Attach for the first time
attach = true;
}
if (attach)
{
context.AttachTo(entitySetName, entity);
}
}
测试方法:
User user = new User(true, false, false);
string commentStr = "This is my comment";
Product product = new Product("ProductName", 7, 0);
TopicFeedbackComment commFeedback = new TopicFeedbackComment(commentStr, new TopicNavigatedUrl("http://testurl.com/test0"), product);
TopicFeedback feedback = new TopicFeedback(sessionID, user, FeedbackState.New);
provider.AddTopicFeedback(feedback);
TopicFeedback addedFeedback = provider.RetrieveTopicFeedback(sessionID);
provider.AddTopicFeedbackComment(commFeedback, sessionID);
一次又一次地运行它,只需插入到
无法发布图像,因此我可以在必要时提供架构。