Devexpress中Gridcontrol查找分组

private void button1_Click(object sender, EventArgs e)
 {
 DataTable dt = new DataTable();
 dt.Columns.Add("Group");
 dt.Columns.Add("idex");
 dt.Columns.Add("name");
 for (int i = 0; i < 5; i++)
 {
 DataRow dr = dt.NewRow();
 dr["Group"] = "<5";
 dr["idex"] = i.ToString();
 dr["name"] = "姓名" + i.ToString();
 dt.Rows.Add(dr);
 }
 for (int i = 5; i <= 10; i++)
 {
 DataRow dr = dt.NewRow();
 dr["Group"] = "(5,10]";
 dr["idex"] = i.ToString();
 dr["name"] = "姓名" + i.ToString();
 dt.Rows.Add(dr);
 }
 for (int i = 10; i <= 15; i++)
 {
 DataRow dr = dt.NewRow();
 dr["Group"] = "(10,15]";
 dr["idex"] = i.ToString();
 dr["name"] = "姓名" + i.ToString();
 dt.Rows.Add(dr);
 }
 gridColumnNumber.FieldName = "idex";
 gridColumnName.FieldName = "name";
 gridColumnGroup.FieldName = "Group";
 gridColumnGroup.GroupIndex = 0;
 gdc.DataSource = dt;
 gdv.ExpandAllGroups();
 for (int i = -1; gdv.IsGroupRow(i); i--)
 {
 DataRow dr = gdv.GetDataRow(gdv.GetDataRowHandleByGroupRowHandle(i));
 if (dr == null) return;
 if (dr["Group"].ToString() == "(5,10]")
 {
 gdv.CollapseAllGroups();
 gdv.FocusedRowHandle = i;
 gdv.SetRowExpanded(i, true);
 return;
 }
 }
 }