Sorting Floating Number in Asp.net,C#,SqlServer

//Code for creating table can be ignored if you are fetching data from DB.
string[] items = { "1.1", "1.2", "1.1.1", "1.2.1", "1.1.2", "1.2", "1.2.1", "1.22.11", "1.3", "1.4" };
DataTable dtItem = new DataTable();
dtItem.Columns.Add("tab_index", typeof(string));
foreach (string item in items)
{
    dtItem.Rows.Add(item);
}
dtItem.AcceptChanges();
//Now just assign this to DataView and sort the same, column has to be string
DataView dvItem = dtItem.DefaultView;
dvItem.Sort = "tab_index";

foreach (DataRowView viewItem in dvItem)
{
    System.Diagnostics.Debug.WriteLine(viewItem["tab_index"].ToString());
}

select columnname from table order by columnname