下拉框下的树形结构数据的绑定

privatevoid BindDropDownList()
{
DataTable dtSite;

/* Get data here
* dtSite = ...
* */

DataRow[] dr = dtSite.Select("PARENTID=0");
for (int i=0; i<dr.Length; i++)
{
//ddlSite is your DropDownList control
ddlSite.Items.Add(new ListItem(dr["NAME"].ToString(), dr["ID"].ToString()));

this.BindData(ddlSite, dtSite, dr["PARENTID"].ToString(), "　");
}
}

privatevoid BindData(DropDownList ddlSite, DataTable dt, string parentID, string blank)
{
DataRow[] dr = dtSite.Select("PARENTID="+ parentID.ToString());
for (int i=0; i<dr.Length; i++)
{
DropDownList ddlSite =new DropDownList();
//ddlSite is your DropDownList control
ddlSite.Items.Add(new ListItem(blank + dr["NAME"].ToString(), dr["ID"].ToString()));

this.BindData(ddlSite, dtSite, dr["PARENTID"].ToString(), blank +"　");
}
}