CODEWITHSUNDEEP
c#linqentity-framework
acbarberi
acbarberi

Reputation: 79

Need to group LINQ to Entities Results

Here is my code:

var context = new InventoryContext();

var res = from i in context.Inventories
          select new FullInventory
          {
              InventoryID = i.InventoryID,
              ItemModelID = i.ItemModelID,
              ModelName = i.ItemModel.ModelName,
              ...
              Quantity = context.Inventories.Select(x => x.ItemModelID).Count()
          };

return res.ToList();

The code I have works great, however the results look like this:

   CATEGORY   | MANUFACTURER | MODEL | QUANTITY
1. Hard drive | Dell         | 250GB | 2
2. Hard drive | Dell         | 250GB | 2

As you can see, I have 2 entries in the table and since those entries are exactly the same, I would like them to be grouped together. To group them together I need to group by ItemModelID, however I still need to put all of the data into a list of FullInventory classes.

How can I group my data together while still "selecting" the data into a list of FullInventory classes?

Upvotes: 0

Views: 143

Answers (3)

Chris Bohatka
Chris Bohatka

Reputation: 363

I would attempt the Group By after retrieving the full list with a Lambda expression:

 var context = new InventoryContext();

 return (from i in context.Inventories
         select new FullInventory
         {
             InventoryID = i.InventoryID,
             ItemModelID = i.ItemModelID,
             ModelName = i.ItemModel.ModelName,
             ...
             Quantity = context.Inventories.Select(x => x.ItemModelID).Count()
         }).GroupBy(g => g.ItemModelID).ToList();

Upvotes: 1

Servy
Servy

Reputation: 203829

Group by that value and then just select out the first item from each group using let.

var res = from inventory in context.Inventories
          group inventory by inventory.ItemModelID into model
          let i = model.FirstOrDefault()
          select [...]

Upvotes: 1

Giannis Paraskevopoulos
Giannis Paraskevopoulos

Reputation: 18411

You may use Distinct()

return res.Distinct().ToList()

Upvotes: 0

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