グリッドの移行 - カスタムの Outlook Group By

public class AlphabetGroupComparer : GroupEqualityComparer<string>
{
      public override bool Equals(string x, string y)
      {
            if (x.Substring(0, 1).ToLower() == y.Substring(0, 1).ToLower())
                  return true;
            return false;
      }
      public override string GroupName(string value)
      {
            if (value.Length == 0)
                  return string.Empty;
            return value.Substring(0, 1).ToUpper();
      }
}
public class DateGroupComparer : GroupEqualityComparer<DateTime>
{
      string[] _groups = new string[] { "1901 - 1950", "1951 - 2000" };
      public override bool Equals(DateTime x, DateTime y)
      {
            if (x.Year < 1951 && y.Year < 1951 || x.Year > 1950 && y.Year > 1950)
                  return true;
            return false;
      }
      public override string GroupName(DateTime value)
      {
            if (value.Year < 1951)
                  return this._groups[0];
            return this._groups[1];
      }
}

ColumnGroupingSetting setting = new ColumnGroupingSetting();
setting.ColumnKey = "FirstName";
setting.GroupComparer = new AlphabetGroupComparer();
this.WebHierarchicalDataGrid1.GroupingSettings.ColumnSettings.Add(setting);
setting = new ColumnGroupingSetting();
setting.ColumnKey = "DOB";
setting.GroupComparer = new DateGroupComparer();
this.WebHierarchicalDataGrid1.GroupingSettings.ColumnSettings.Add(setting);