需要帮助来形成LINQ to SQL表达式

Question

Got a table with column names as such

Name | ProductID | Price | Category | SubCategory

I am passing a category name into an action method and I want to return the subcategory names that are on the same row as the category name that is passed in.

So something like this, except this is wrong:

var subcategories = 
      productsRepository.Products
                        .Select(x => x.SubCategory.Where(x.Category == category);

So I can then collect the distinct subcategory names with this:

foreach (string subcategoryName in subcategories.Distinct().OrderBy(x => x))

Thanks.

Answer 1

Are you looking for:

var subcategories = productsRepository.Products
                                      .Where(x => x.Category == category)
                                      .Select(x => x.SubCategory)
                                      .Distinct()
                                      .OrderBy(x => x);

On another note, it does appear that your database isn't normalized.

Answer 2

I'm not sure I totally understand the problem, but wouldn't you be better off filtering initially and then selecting the column?

var subcategories = 
      productsRepository.Products.Where(x=>x.Category==category)
                        .Select(x => x.SubCategory);