LINQ group

DataTable dt = new DataTable();
dt = GetDataSource();

var codeQuery =
    from code in dt.AsEnumerable()
    group code by code["group"] into g
    orderby g.Key
    select g;

foreach (var item in codeQuery)
{
    Response.Write(item.Key + "
");

    foreach (var d in item)
    {
        Response.Write("***" + d["value"] + " " + d["text"] + " " + d["display"] + " " + d["group"] + " " + "
");
    }

}

分組資料
group 子句 (C# 參考)

LINQ: How to get the latest/last record with a group by clause
C#: Left outer joins with LINQ

利用LINQ GroupBy快速分組歸類