Question

I want to make an MVC C# List with unique values in it. Here is the scenario. My List is like this:

List A

ItemNo       FileName 

001      =>   A.txt
001      =>   B.txt
002      =>   A.txt
002      =>   B.txt
003      =>   A.txt

I want to make it a new List like,

List B

ItemNo       FileName 

001      =>   A.txt, B.txt
002      =>   A.txt, B.txt
003      =>   A.txt

Is there any way that I can make it workable?

Answer 1

You can use LINQ with GroupBy, assume you have class:

class Item
{
    public string ItemNo { get; set; }
    public string FileName { get; set; }
}

var result = list.GroupBy(item => item.ItemNo)
                 .Select(g => new Item
                   {
                       ItemNo = g.Key,
                       FileName = string.Join(", ",  g.Select(s => s.FileName))
                   });