DropDownList无限级分类(灵活控制显示形式)

主要使用递归实现，数据库结构：

最终样式：

protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
           BindDrpClass();
        }
    }
    //绑定顶级分类
    private void BindDrpClass()
    {
        Bll.Class classSystem = new Bll.Class();
        DataTable dt = classSystem.GetClassList("").Tables[0];
        ddlClass.Items.Clear();
        ddlClass.Items.Add(new ListItem("添加根栏目","0"));
        DataRow[] drs = dt.Select("ParentID= " + 0);

        foreach (DataRow dr in drs)
        {
            string classid = dr["ClassID"].ToString();
            string classname = dr["ClassName"].ToString();
            //顶级分类显示形式
            classname = "╋" + classname;

            ddlClass.Items.Add(new ListItem(classname, classid));
           int sonparentid = int.Parse(classid);
            string blank = "├";
            //递归子分类方法
            BindNode(sonparentid, dt, blank);
        }
        ddlClass.DataBind();
    }
    //绑定子分类
    private void BindNode(int parentid, DataTable dt, string blank)
    {
        DataRow[] drs = dt.Select("ParentID= " + parentid);

        foreach (DataRow dr in drs)
        {
            string classid = dr["ClassID"].ToString();
            string classname = dr["ClassName"].ToString();

            classname = blank + classname;
            ddlClass.Items.Add(new ListItem(classname, classid));

            int sonparentid = int.Parse(classid);
            string blank2 = blank + "─";

            BindNode(sonparentid, dt, blank2);
        }
    }

 

 

public DataSet GetClassList(string strWhere)
        {
            StringBuilder strSql = new StringBuilder();
           strSql.Append("select * from tb_Class ");
            if (strWhere.Trim() != "")
           {
               strSql.Append(" where " + strWhere);
            }
             return SqlHelper.ExecuteDataset(SqlHelper.ConnString, CommandType.Text, strSql.ToString());
        }

来源：http://www.cnblogs.com/chensubo/archive/2008/02/11/1067037.html