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Create all possible combinations of items in a list using Linq and C #

I have a category table:

 Catid | Desciption
 1 | Color
 2 | Size
 3 | Material

And a table of category items

 Catid | Name
 1 | Red
 1 | Blue
 1 | Green
 2 | Small
 2 | Med
 2 l Large
 3 | Cotton
 3 | Silk

I need to skip all the elements and display them in such labels:

 Red Small Cotton
 Red Small Silk
 Red Med Cotton
 Red Med Silk
 Red Large Cotton
 Red Large Silk
 Blue Small Cotton
 Blue Small Silk
 Blue Med Cotton
 Blue Med Silk
 Blue Large Cotton
 Blue Large Silk
 Green Small Cotton
 Green Small Silk
 Green Med Cotton
 Green Med Silk
 Green Large Cotton
 Green Large Silk

Please note: there may be more or less categories. This is not predetermined.

Any suggestions? Thanks you

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2 answers
var result = list.GroupBy(t => t.Id).CartesianProduct();

Using CartesianProduct Extension Method from Eric Lippert Blog

static IEnumerable<IEnumerable<T>> CartesianProduct<T>(
  this IEnumerable<IEnumerable<T>> sequences) 
{ 
  IEnumerable<IEnumerable<T>> emptyProduct = new[] { Enumerable.Empty<T>() }; 
  return sequences.Aggregate( 
    emptyProduct, 
    (accumulator, sequence) => 
      from accseq in accumulator 
      from item in sequence 
      select accseq.Concat(new[] {item})); 
}

Example:

var list = new[]
{
    new { Id = 1, Description = "Red"    },
    new { Id = 1, Description = "Blue"   },
    new { Id = 1, Description = "Green"  },
    new { Id = 2, Description = "Small"  },
    new { Id = 2, Description = "Med"    },
    new { Id = 2, Description = "Large"  },
    new { Id = 3, Description = "Cotton" },
    new { Id = 3, Description = "Silk"   },
};

var result = list.GroupBy(t => t.Id).CartesianProduct();

foreach (var item in result)
{
    Console.WriteLine(string.Join(" ", item.Select(x => x.Description)));
}

Conclusion:

Red Small Cotton
Red Small Silk
Red Med Cotton
Red Med Silk
Red Large Cotton
Red Large Silk
Blue Small Cotton
Blue Small Silk
Blue Med Cotton
Blue Med Silk
Blue Large Cotton
Blue Large Silk
Green Small Cotton
Green Small Silk
Green Med Cotton
Green Med Silk
Green Large Cotton
Green Large Silk
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Try Cross Connect

var combo = from l1 in LIst1
            from l2    in List2
            select new {l1, l2};
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