Question

I’m creating import from XML function for categories.
First of all, using XDocument, I create list of categories to be added. I turned off isIdentity option for ID in Categories table, because I’m planning to use ID from XML.

XML example:

<cat>
<id>17</id>
<name>Category name</name>
<parent_id>0</parent_id>
</cat>

Then, I wrote method, which tries to get category by ID and update, or insert new:

var category = _categoryService.GetCategoryById(Id);
        if (category != null)
        {
            category.Name = model.Name;
            category.ParentCategoryId = model.ParentCategoryId;
            category.UpdatedOnUtc = DateTime.UtcNow;
            category.Published = true;
            category.Deleted = false;

            _categoryService.UpdateCategory(category);
        }
        else
        {
            category = new Core.Domain.Catalog.Category();

            category.Id = model.Id;
            category.ParentCategoryId = model.ParentCategoryId;
            category.Name = model.Name;
            category.UpdatedOnUtc = DateTime.UtcNow;
            category.CreatedOnUtc = DateTime.UtcNow;
            category.Published = true;
            category.Deleted = false;

            _categoryService.InsertCategory(category);
        }

And then comes the most weird – application throws exception: Cannot insert the value NULL into column ‘Id’, table ‘nopCommerce.dbo.Category’; column does not allow nulls. INSERT fails.
The statement has been terminated.
BUT even in debugger, category ID is not null.. Asking for help!
Thanks in advance!

Update: InsertCategory is a standard nopCommerce method:

 /// <summary>
    /// Inserts category
    /// </summary>
    /// <param name="category">Category</param>
    public virtual void InsertCategory(Category category)
    {
        if (category == null)
            throw new ArgumentNullException("category");

        _categoryRepository.Insert(category);

        //cache
        _cacheManager.RemoveByPattern(CATEGORIES_PATTERN_KEY);
        _cacheManager.RemoveByPattern(PRODUCTCATEGORIES_PATTERN_KEY);

        //event notification
        _eventPublisher.EntityInserted(category);
    }

Answer 1

I just found out, that I need to change mapping class as well as database, removing autonumber option from ID. That was another pain, but solution is:

instead of this.HasKey(c=>c.Id) use:

this.Property(c=>c.Id).HasDatabaseGeneratedOption(DatabaseGeneratedOption.None) ;