DropDownList实现树形结构显示

public System.Web.UI.WebControls.DropDownList AddDropDownList (System.Web.UI.WebControls.DropDownList droplist, int ParentID, ListItem plist)
{
string NodeId = "ID";
string ParentId = "ParentId";
string NodeName = "Name";

//DataSet dsFlowType = myData.GetFlowTypeDS();
DataView dvTree = new DataView(dsFlowType.Tables[0]);

//过滤ParentId,得到当前的所有子节点
dvTree.RowFilter = ParentId + " = " + ParentID.ToString();
foreach (DataRowView drv in dvTree)
{
//-----------------------------------------
int depth = 0;
int NodeID = Convert.ToInt32(drv[NodeId]); ;
Depth(NodeID, ref depth); //计算当前节点深度

string blank = "";
if (ParentID != 0)
{
for (int i = 1; i <= depth; i++) { blank += "|－"; } } //----------------------------------------- ListItem list = new ListItem(); list.Text = blank + drv[NodeName].ToString().Trim(); list.Value = drv[NodeId].ToString().Trim(); droplist.Items.Add(list); //***注意区别:根节点 AddDropDownList(droplist, Int32.Parse(drv[NodeId].ToString().Trim()), list); //递归 } return droplist; } //计算当前节点深度 public int Depth(int NodeID, ref int depth) { string NodeId = "ID"; string ParentId = "ParentId"; //DataSet dsFlowType = myData.GetFlowTypeDS(); DataView dvTree = new DataView(dsFlowType.Tables[0]); //过滤ParentId,得到当前的所有父节点 dvTree.RowFilter = NodeId + " = " + NodeID.ToString(); foreach (DataRowView drv in dvTree) { int ID = Convert.ToInt32(drv[ParentId]); if (ID != 0) { depth += 1; Depth(ID, ref depth); //递归 } } return depth; }