ASP.NET Entity Framework Update SQL set int value to 0 - sql-server

Question

I have a SQL column as an int data type.
I'm trying to update en entry using Entity Framework, setting it's value to 0 but it does not get updated. I also don't get an error when Submitting Changes... Odd. Well I changed the Tag Name and set the count to 0, the name got updated but the count was not modified
Any ideas?
Thanks in advance
Code Snipet:
Add Tag - up the tag count:
Tag tag = _tagsRepository.GetTagByName(TagName);
if (tag == null)
{
tag = new Tag();
tag.CreateDate = DateTime.Now;
tag.Name = TagName;
tag.Count = 1;
}
else
{
tag.Count += 1;
}
tag = _tagsRepository.SaveTag(tag);
Remove tag from an item, update the tag count
Tag tag = _tagsRepository.GetTagByName(TagName);
if (tag != null)
{
tag.Count -= 1;
}
tag = _tagsRepository.SaveTag(tag);
GetTagByName Method
public Tag GetTagByName(string Name)
{
Tag result = null;
using (ISADataContext dc = conn.GetContext())
{
result = dc.Tags.Where(t => t.Name == Name).FirstOrDefault();
}
return result;
}
SaveTag Method
public Tag SaveTag(Tag tag)
{
using (ISADataContext dc = conn.GetContext())
{
if (tag.TagID > 0)
{
dc.Tags.Attach(new Tag { TagID = tag.TagID });
dc.Tags.ApplyCurrentValues(tag);
}
else
{
dc.Tags.AddObject(tag);
}
dc.SaveChanges();
}
return tag;
}
Workaround:
using (ISADataContext dc = conn.GetContext())
{
if (tag.TagID > 0)
{
if (tag.Count == 0)
{
Tag t = dc.Tags.Where( tt=> tt.TagID == tag.TagID).First();
t.Count = 0;
}
else
{
dc.Tags.Attach(new Tag { TagID = tag.TagID });
dc.Tags.ApplyCurrentValues(tag);
}
}
else
{
dc.Tags.AddObject(tag);
}
dc.SaveChanges();
}
return tag;

Answer 1

You shouldn't wrap your DataContext in using statements in your scenario. Doing this means that you're retrieving the object in one context and trying to save the existing object in a new context. This means that when you're trying to save in the second context, it has no idea that the object already exists in the database.

Answer 2

I ran into the same problem as yours - every other value except 0 works fine. Can we get some solution to this?
EDIT: After some research, I found a way to fix this. You have to modify this line:
dc.Tags.Attach(new Tag { TagID = tag.TagID });
In the stub object, add the problematic property (in your case Count) and set its value to something that is never possible in the db, for example -2. In this way, the EF context will also compare the count value of the attached object and will always know there is a difference. So your line becomes:
dc.Tags.Attach(new Tag { TagID = tag.TagID, Count = -2 });
I am not sure if this will work every time, but for now it seems to do the job.