Question

I have this following class:

public class TV
{
    public string GroupId { get; set; }
    public string Title { get; set; }
    public string Genre { get; set; }
}

Then I have this following list (which is dynamic created and will never be same):

List<TV> myList = new List<TV>();
myList.Add(new TV { GroupId = "1", Title = "Title 1", Genre = "Genre A" });
myList.Add(new TV { GroupId = "1", Title = "Title 2", Genre = "Genre A" });
myList.Add(new TV { GroupId = "1", Title = "Title 3", Genre = "Genre A" });
myList.Add(new TV { GroupId = "3", Title = "Title 4", Genre = "Genre 18" });
myList.Add(new TV { GroupId = "A", Title = "Title 5", Genre = "Genre 18" });
myList.Add(new TV { GroupId = "A", Title = "Title 6", Genre = "Genre A" });
myList.Add(new TV { GroupId = "B", Title = "Title 7", Genre = "Genre A" });
myList.Add(new TV { GroupId = "C", Title = "Title 8", Genre = "Genre A" });
myList.Add(new TV { GroupId = "D", Title = "Title 9", Genre = "Genre 18" });
myList.Add(new TV { GroupId = "D", Title = "Title 10", Genre = "Genre A" });
myList.Add(new TV { GroupId = "D", Title = "Title 11", Genre = "Genre A" });
myList.Add(new TV { GroupId = "E", Title = "Title 12", Genre = "Genre A" });

I have the following (hardcoded) navigation categories that are links:

[0-9] [ABC] [DEF] [GHI] [JKL] [MNO] [PQR] [STU] [VWXYZ]

I’m trying to loop myList and by looking at the GroupId property, I want to place it in the appropriate div so I end up having divs like this:

<div id="group-09">
<div>
    1, Title 1, Genre A
    1, Title 2, Genre A
    1, Title 3, Genre A
    3, Title 4, Genre 18
</div>
</div>

<div id="group-ABC">
<div>
    A, Title 5, Genre 18
    A, Title 6, Genre A
    B, Title 7, Genre A
    C, Title 8, Genre A
</div>
</div>

<div id="group-DEF">
<div>
    D, Title 9, Genre 18
    D, Title 10, Genre A
    D, Title 11, Genre A
    E, Title 12, Genre A
</div>
</div>

I can’t seem to figure out the logic to properly do this!
Does anyone have a suggestion?
Thanks

Answer 1

You can create a dictionary that maps GroupIds to <div> ids and group the items in myList by <div> id:

var groups = new Dictionary<string, string>
{
    { "0", "group-09" },
    { "1", "group-09" },
    { "2", "group-09" },
    ...
    { "A", "group-ABC" },
    ...
};

var query = from item in myList
            group item by groups[item.GroupId];

foreach (var group in query)
{
    Console.WriteLine("id: " + group.Key);
    foreach (var item in group)
    {
        Console.WriteLine("       " + item.Title);
    }
}