DropDownList分级绑定显示数据

public void BuildDropDownList(DropDownList ddl, int pareId, DataTable dt, int vrank)
{
foreach (DataRow dr in dt.Rows)
{
if (Convert.ToInt32(dr["sort"]) == pareId)
{

ListItem li = new ListItem();

string frontStr = "";

if (Convert.ToInt32(dr["sort"]) != vrank)
{
//for (int i = vrank; i < DAL.activity.GetRecordCount(" sort =" + Convert.ToInt32(dr["sort"])); i++)
//{
//    frontStr += "　";
//}
frontStr += " └";
}

li.Text = frontStr + dr["name"].ToString();
li.Value = dr["aid"].ToString();

ddl.Items.Add(li);

BuildDropDownList(ddl, Convert.ToInt32(dr["aid"]), dt, vrank);
}
}
}

<pre name="code" class="csharp">BuildDropDownList(DropDownList ddl, int pareId, DataTable dt, int vrank)