public static DataTable SelectTopFrom(DataTable dt, int rowCount)
    {
        DataTable dtn = dt.Clone();
        for (int i = 0; i < rowCount; i++)
        {
            dtn.ImportRow(dt.Rows[i]);
        }
        return dtn;
    }
 
    public static DataView SelectTopFrom(DataView dv, int rowCount)
    {
        DataTable dt = CreateTable(dv);
        DataTable dtn = dt.Clone();
        for (int i = 0; i < rowCount; i++)
        {
            dtn.ImportRow(dt.Rows[i]);
        }
        DataView dvn = new DataView(dtn);
        return dvn;
    }