ID value is being changed when added to database, different from posted and submitted values

I have a form that creates a new brand. The user chooses a name, image, and website url for the brand and hits submit. The edit scenario works the same way. The issue I'm having is when creating a new brand, the correct imageId 开发者_JAVA百科is being posted, and right up to SaveChanges() in my action its correct. When I check the new row in the database, the ID has been doubled and then some. (for example if I submit 37, the database changes it to 78, 38 to 80 etc.) I'm stumped as to why this is happening. Here's my action:

    [HttpPost]
    public ActionResult NewBrand(Brand brand)
    {
        try
        {
            brand.BrandName = Request.Form["BrandName"];
            brand.BrandImageId = int.Parse(Request.Form["Image.ImageId"]);
            brand.BrandWebsite = Request.Form["BrandWebsite"];

            _entities.Brands.AddObject(brand);
            _entities.SaveChanges();

            return RedirectToAction("Brands");
        }
        catch (Exception ex)
        {
            var script = "alert(" + ex.Message + ")";

            return JavaScript(script);
        }
    }

And heres an example POST from firebug

Parametersapplication/x-www-form-urlencoded
BrandName    Sample Brand
BrandWebsite    www.somewebsite.com
Image.ImageId    37
Source
Content-Type: application/x-www-form-urlencoded Content-Length: 72 
BrandName=Sample+Brand&Image.ImageId=37&BrandWebsite=www.somewebsite.com

I am using the entity framework and built my database using the wizards in visual studio. My brands table has the foreign key ImageId and i have an image table with the primary key ImageId, they have a one to many relationship. Any ideas?

edit

I created the entity framework object by right-clicking my models folder and adding a new .edmx file. And then I right clicked in the design view and hit "update from database" and it created a model from the tables I created. I haven't done any special configuration or setup beyond this, nor am I using the repository pattern (yes, that means I have data access code in my controllers, I am refactoring this weekend) which I learned after starting this project.

_entities comes from this line at the top of the controller

private MHNHubEntities _entities = new MHNHubEntities(); 

ObjectContext implements IDisposable, so you aren't using your MHNHubEntities object correctly. Try to modify your code accordingly and see if it solves the problem.

[HttpPost]
public ActionResult NewBrand(Brand brand)
{
    try
    {
        brand.BrandName = Request.Form["BrandName"];
        //brand.BrandImageId = int.Parse(Request.Form["Image.ImageId"]); // edited out
        brand.BrandWebsite = Request.Form["BrandWebsite"];

        using (var _entities = new MHNHubEntities())
        {
            // Edited in
            brand.BrandImage = _entities.
                                BrandImages.
                                FirstOrDefault(i => 
                                  i.Id == int.Parse(Request.Form["Image.ImageId"]));

            _entities.Brands.AddObject(brand);
            _entities.SaveChanges();
        }

        return RedirectToAction("Brands");
    }
    catch (Exception ex)
    {
        var script = "alert(" + ex.Message + ")";

        return JavaScript(script);
    }
}

I eventually solved the issue by looking up the image using the image id and then assigning that image to the BrandImage property, instead of assigning the ID to BrandImageID, which was adding a new, blank Image to the database.