CODEWITHSUNDEEP
asp.net-mvclinq
Moe Bataineh
Moe Bataineh

Reputation: 1080

LINQ Combine two tables

Currently I have 2 database tables which looks like:

---------------        --------------------
|  Categories |        |  Item_Categorys  |
---------------        --------------------
|      id     |        |        id        |
|     Title   |        |   Category_ID    |
---------------        |      Item_ID     |
                       --------------------

I have a Model which displays Checkboxes on my View which is like

LocalCategoryModel
-------------------
int categoryid
string category_title
bool ischecked

I'm trying to get all the items categorys from the table and then get all the category rows then crosscheck them to where if there's a category item, it Puts it in a IEnumerable. So at the end, the LocalCategory has all the categories and then the ischecked is set to true or false depending on if it has a row in the Item_Categorys sql table.

Upvotes: 1

Views: 3557

Answers (3)

roman
roman

Reputation: 117445

class Category { public int id; public string Title; };
class CategoryItem { public int category_id; public int item_id; }
class Category { public int id; public string title; };

// Create categories list
var categories = new List<Category>() { new Category { id = 1, title = "First" }, new Category { id = 2, title = "Second" } };

// Create categories items list
var categories_items = new List<CategoryItem>() { new CategoryItem { category_id = 1, item_id = 2 } };

// All categories in categories_items
var categories_items_set = categories_items.Select(x => x.category_id).Distinct();

// Final query
var q = categories.Select(x => new { categoryid = x.id, category_title = x.title, ischecked = categories_items_set.Contains(x.id) });
q.ToList()

// output
categoryid = 1, category_title = First, ischecked = True
categoryid = 2, category_title = Second, ischecked = False

Upvotes: 0

chamara
chamara

Reputation: 12709

public class LocalCategoryModel
    {
        public int categoryid { get; set; }
        public string category_title { get; set; }
        public bool ischecked { get; set; }
    }

public IEnumerable<LocalCategoryModel> getSourec()
        {
            IEnumerable<LocalCategoryModel> query = from tbcat in Categories
                        join tbitem_cat in dc.Item_Categorys
                        on  tbcat.id equals tbitem_cat.Category_ID into ct
                        from tbitem_cat in ct.DefaultIfEmpty()
                        select new LocalCategoryModel
                        {
                            categoryid = tbcat.id,
                            category_title = tbcat.Title,
                            ischecked = tbitem_cat == null ? false : true
                        };

            return query;
        }

Upvotes: 1

carbonara
carbonara

Reputation: 49

I'll get you some example.

It helps you.

I refer to a book named 'C# 4.0 IN A NUTSHELL'.

// outer collection
customers.Join (
      purchases,                  // inner collection
      c => c.ID,                  // outer key selector
      p => p.CustomerID,          // inner key selector
      (c, p) => new { c, p } )    // result selector
  .OrderBy (x => x.p.Price)
  .Select  (x => x.c.Name + " bought a " + x.p.Description);

 from c in customers
 join p in purchases on c.ID equals p.CustomerID
 select new { c.Name, p.Description, p.Price };

Upvotes: 0

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