如何使用数据属性对列表项进行分组？

Question

How can i group a List Items based data attribute data-group? I am trying to avoid duplicate in my list based on the following conditions.

My Conditions are:

1. If Same PartyName and SubPartyName appears multiple times I want to merge them
2. If same PartyName but different subPartyName group by PartyName .

Below is my code to create a list:

    <ul id="list">
     @foreach (var item in Info){
      <li data-group="@item.PartyName" data-expanded="true"> @item.PartyName
         <ul>
             <li data-group="@item.SubPartyName" data-expanded="true">@item.subPartyName</li>
         </ul>
     </li>
     }</ul>

My current list looks like as shown below:

Party A

• SubParty A

Party A

• SubParty B

Party A

• SubParty B

Party A
Party B
Party C

I Would like to see my list as:

---

Party A

• SubParty A
• SubParty B

Party B
Party C

Answer 1

You can do like this

 public class InfoClass
{
    public string PartyName { get; set; }
    public string SubPartyName { get; set; }
}

public class NewInfoClass
{
    public string PartyName { get; set; }
    public List<string> SubPartyName { get; set; }
}

Controller Action

public ActionResult Index()
    {
        List<InfoClass> infos = new List<InfoClass>();
        infos.Add(new InfoClass() { PartyName = "Party A", SubPartyName = "SubParty A" });
        infos.Add(new InfoClass() { PartyName = "Party A", SubPartyName = "SubParty B" });
        infos.Add(new InfoClass() { PartyName = "Party A", SubPartyName = "SubParty B" });
        infos.Add(new InfoClass() { PartyName = "Party A" });
        infos.Add(new InfoClass() { PartyName = "Party B" });
        infos.Add(new InfoClass() { PartyName = "Party C" });

        var results = from p in infos
                      group p.SubPartyName by p.PartyName into g
                      select new { PartyName = g.Key, SubPartyNames = g.ToList().Distinct() };

        List<NewInfoClass> newList = new List<NewInfoClass>();

        int count = 0;
        foreach (var item in results)
        {
            newList.Add(new NewInfoClass()
            {
                PartyName = item.PartyName,
            });
            newList[count].SubPartyName = new List<string>();
            foreach (var item2 in item.SubPartyNames)
            {
                if (item2 != null)
                {
                    newList[count].SubPartyName.Add(item2);
                }
            }
            count++;
        }
        return View(newList);
    }

View

@model List<DemoApplication.Models.NewInfoClass>
<ul id="list">
@foreach (var item in Model)
{
    <li data-group="@item.PartyName" data-expanded="true">
        @item.PartyName
        @foreach (var item2 in item.SubPartyName)
        {
            <ul>
                <li data-group="@item2" data-expanded="true">@item2</li>
            </ul>
        }
    </li>
}