实体框架4-删除对象

Question

我的数据库中有3个表

CmsMasterPages
CmsMasterPagesAdvSlots (Pure Juction Table)
CmsAdvSlots

这是我的EDM图片：

我需要找出所有与CmsMasterPage连接的对象CmsAdvSlot（它在我的代码发布后才起作用），然后从数据库中删除结果（CmsAdvSlot）。

我的问题是找到主题后我无法删除该对象 。

Error: The object cannot be deleted because it was not found in the ObjectStateManager. 

---

        int findMasterPageId = Convert.ToInt32(uxMasterPagesListSelector.SelectedValue);
        CmsMasterPage myMasterPage = context.CmsMasterPages.FirstOrDefault(x => x.MasterPageId == findMasterPageId);
        var resultAdvSlots = myMasterPage.CmsAdvSlots;
        // It is working until here
        foreach (var toDeleteAdv in resultAdvSlots)
        {
            context.DeleteObject(myMasterPage.CmsAdvSlots.Any()); // ERORR HERE!!
            context.SaveChanges();
        }

---

知道如何解决吗？ 谢谢你的时间！ :-)

Answer 1

尝试这个：

while (myMasterPage.CmsAdvSlots.Count > 0)
{
  var slot = myMasterPage.CmsAdvSlots.First();
  myMasterPage.CmsAdvSlots.Remove(slot); // This is required only in some scenarios - it depends on type of entities you are using.
  context.DeleteObject(slot);
}

context.SaveChanges();

Answer 2

.Any()返回一个布尔值。 使用.First()代替， .First()在您的情况下将返回第一个CmsAdvSlot 。

如果要删除所有CmsAdvSlot ，请遵循@Ladislav Mrnka的示例。

Answer 3

在context.DeleteObject(myMasterPage.CmsAdvSlots.Any());
myMasterPage.CmsAdvSlots.Any()应该返回布尔值，您应该尝试使用myMasterPage.CmsAdvSlots.First()代替！