Convert List<T> into another List<T> that contains another List<T>

Question

I have a list of Foo:

class Foo {
    public int Id { get; set; }
    public String Name { get; set; }
}

And I want to convert it to a list Bar:

class Bar {
    public int Id { get; set }
    public List<String> NameList { get; set; }
}

The data in Foo looks like this:

Id     Name
-----------
1      Foo1
1      Foo2
1      Foo3
2      Foo3
2      Foo2
2      Foo1

And I want it to look like this:

Id      NameList
----------------
1      Foo1
       Foo2
       Foo3
2      Foo3
       Foo2
       Foo1

I'm doing this so it will be easier to display in a Razor rendered Html unordered list. Also, if there is an easy way to do this without conversion, please let me know.

Ultimately, I will display the Html like this:

<li>1
    <ul>
        <li>Foo1</li>
        <li>Foo2</li>
        <li>Foo3</li>
    </ul>
</li>
<li>2
    <ul>
        <li>Foo3</li>
        <li>Foo2</li>
        <li>Foo1</li>
    </ul>
</li>

So far I've tried the following Linq code, but it didn't work

BarList = FooList.Select(x => new Bar() {
    Id = x.Id,
    NameList = x.Select(y => y.)
}).ToList();

Answer 1

Use GroupBy.

List<Bar> BarList = FooList.GroupBy(f => f.Id, f => f.Name, (id, names) => new Bar
{
    Id = id,
    NameList = names.ToList()
}).ToList();