Question

I have a little program that uses ObjectListView to visualise the database information. Currently I am trying to add items and keep getting The operation cannot be completed because the DbContext has been disposed. Which is highlighting the olvEntityTypes.AddObject(et); line below.

Code:

string typeName = tbTypeName.Text;
string desc = tbDesc.Text;

EntityTypes et;
using (FCERTSModelContainer db = new FCERTSModelContainer())
{
    // Create and save new row for the EntityTypes table.
    et = new EntityTypes { EntityTypeName = typeName, Description = desc };
    db.EntityTypes.Add(et);
    db.SaveChanges();

    olvEntityTypes.AddObject(et);
}

• I suspected that SaveChanges() might also be closing the context, but trying to add the object before saving changes still throws the same error.
• Putting olvEntityTypes.AddObject(et); outside of the using block is also a failure.
• If I query the database with something like the following, no errors are thrown;

Code:

var query = from ent in db.EntityTypes
            orderby ent.EntityTypeName
            select ent;

olvEntityTypes.SetObjects(query);

So I’m at a bit of a loss now as to why this is throwing errors and how to fix it.

Answer 1

It turns out the problem was the initial setting of objects for the objectlistview. I was using this piece of code;

var query = db.EntityTypes.OrderBy(eg => eg.EntityTypeName);
olvEntityTypes.SetObjects(query);

Which works fine, but is in a different using block in my codebase and as such, a completely different DbContext.

If I convert the query to a List and then call SetObjects() the entire program works without fault.