最简单的方法来删除对象与实体框架4 [英] Simplest Way to Delete Object with Entity Framework 4

问题描述

确认！我是新来的实体框架，并想找到要删除某个项目的最简单方法。

Ack! I'm new to Entity Framework and am trying to find the simplest way to delete an item.

我有一个数据源设置为从数据库TagCategory对象列表框。这是工作的罚款。现在我想删除选定的项目。所以，我做这样的事情：

I have a listbox with the datasource set to TagCategory objects from the database. This is working fine. Now I'd like to delete the selected item. So I do something like this:

TagCategory category = (TagCategory)lstCategories.SelectedItem;
using (MyEntities context = new MyEntities())
{
    context.AttachTo("TagCategories", category);
    context.DeleteObject(category);
    context.SaveChanges();
}

这似乎直截了当不够，但它不工作。没有被删除，没有错误消息，什么都没有。

This seems straight forward enough, but it doesn't work. Nothing is deleted, no error message, nothing.

因此​​，我认为我可以，而不是做这样的事情：

So I see I can instead do something like this:

using (MyEntities context = new MyEntities())
{
    string cmd = String.Format("DELETE FROM TagCategory WHERE TagCatID=@ID",
        category.TagCatID));
    context.ExecuteStoreCommand(qry);
}

这似乎工作。所以，不要我去什么工作，或者是实体框架4居然能够做到这一点？

That seems to work. So do I just go with what works, or is Entity Framework 4 actually capable of doing this?

编辑：没关系。其实，我有另一个问题，prevented的code形式执行。这两个片段我张贴似乎工作好。我的道歉。的

Nevermind. In fact, I had another issue that prevented the code form executing. Both snippets I posted seem to work okay. My apologies.

推荐答案

您可以使用存根实体，是这样的：

You can use stub entity, something like this:

using (var context = new MyEntities())
{
     var tagCategory = new TagCategory
     {
         PostId = category.TagCatID
     };
     context.TagCategories.Attach(tagCategory);
     context.DeleteObject(tagCategory);
     context.SaveChanges();
}

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