OrderByは拡張メソッドでUsing System.Linqが無いと使えない
private void Form1_Load(object sender, EventArgs e)
{
var lst = CreateList(new { Id = 0, Name = "" });
lst.Add(new { Id = 31, Name = "Jan" });
lst.Add(new { Id = 28, Name = "Feb" });
lst.Add(new { Id = 31, Name = "Mar" });
lst.Add(new { Id = 30, Name = "Apr" });

foreach (var item in lst.OrderBy(t => t.Id))
{
Console.WriteLine("{0}{1}", item.Id, item.Name);
}
}
private List<T> CreateList<T>(T val)
{
return new List<T>();
}