Function to bind Multilevel category in dropdown list

int level = -1;
private void RecursiveFillTree(DataTable dtParent, int parentID)
{
level++; //on the each call level increment 1
StringBuilder appender = new StringBuilder();
for (int j = 0; j < level; j++)
appender.Append(“&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;”);
if (level > 0)
appender.Append(“|__”);

DataView dv = new DataView(dtParent);
dv.RowFilter = string.Format(“cat_ParentId = {0}”, parentID);
int i;
if (dv.Count > 0)
{
for (i = 0; i < dv.Count; i++)
{
drpdwnsub.Items.Add(new ListItem(Server.HtmlDecode(appender.ToString() + dv[i][“cat_name”].ToString()), dv[i][“cat_Id”].ToString()));
RecursiveFillTree(dtParent, int.Parse(dv[i][“cat_Id”].ToString()));
}
}
level–; //on the each function end level will decrement by 1
}