消息回答按父消息分组

我需要按消息答案分组，像这样:

• 消息id = 1
• 消息应答id = 2/父消息id = 1
• 消息应答id = 3/父消息id = 1

• 留言应答id = 4/家长留言id = 1

• 消息id = 5

• 消息应答id = 6/父消息id = 5
• 消息应答id = 7/父消息id = 5
• 消息应答id = 8/父消息id = 5

消息模型:

public class Message
{
    // Primary properties
    public int Id { get; set; }
    public string NameFrom { get; set; }
    public string EmailFrom { get; set; }
    public string TelephoneFrom { get; set; }
    public string NameTo { get; set; }
    public string EmailTo { get; set; }
    public string TelephoneTo { get; set; }
    public string Title { get; set; }
    public string MessageText { get; set; }
    public bool? Approved { get; set; }
    public DateTime DateCreated { get; set; }
    public DateTime? DateRead { get; set; }
    // Navigation properties
    public Member MemberFrom { get; set; }
    public Member MemberTo { get; set; }
    public MessageType MessageType { get; set; }
    public Message MessageParent { get; set; }
    public Ad Ad { get; set; }
    public Ask Ask { get; set; }
}

在视图中显示:

@foreach (var item in Model)
{
    <div class="message_link_container" id="linkmessage_@item.Id">
        <ul class="estr_message" id="estrmessage_@item.Id">
            <li id="email_@item.Id">
                <p>@if(item.MessageParent_Id == 0){ if(string.IsNullOrEmpty(item.NameFrom)) { @item.EmailFrom } else { @item.NameFrom } }</p>
            </li>
            <li id="title_@item.Id">
                <p>@item.Title</p>
            </li>
            <li id="date_@item.Id">
                <p>@item.DateCreated</p>
            </li>
        </ul>
    </div>
}

var model=Messages
             .OrderBy(o=>o.MessageParent_Id==0?Id:o.MessageParent_Id)
             .ThenBy(o=>o.Id);