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  • 树形结构 DropDownList

    前台

       <asp:DropDownList ID="ddlOutType" runat="server" />

    后台代码:


    先绑定第一级

                    string SQL = "SELECT CategoryID,CategoryName,ParentID FROM Category"    
                DataTable datatable = SqlHelper.ExecuteDataTable(SQL);
                    DataRow[] row = datatable.Select("ParentID='0'");
                    //添加根目录
                    for (int i = 0; i < row.Length; i++)
                    {
                        ListItem li = new ListItem(row[i]["CategoryName"].ToString(), row[i]["CategoryID"].ToString());
                        ddlOutType.Items.Add(li);
                        addOtherDll("", Convert.ToInt32(row[i]["CategoryID"]), datatable, 1, ddlOutType);
                    }


    递归查找下级

          /// <param name="Pading">空格</param>
            /// <param name="DirId">父路径ID</param>
            /// <param name="datatable">返回的datatable</param>
            /// <param name="deep">树形的深度</param>
            private void addOtherDll(string Pading, int DirId, DataTable datatable, int deep,DropDownList ddl)
            {
                DataRow[] rowlist = datatable.Select("ParentID='" + DirId + "'");
                foreach (DataRow row in rowlist)
                {
                    string strPading = "";
                    for (int j = 0; j < deep; j++)
                    {
                        strPading += " "; //用全角的空格
                    }
                    //添加节点
                    ListItem li = new ListItem(strPading + "|--" + row["CategoryName"].ToString(),row["CategoryID"].ToString());
                    ddl.Items.Add(li);
                    //递归调用addOtherDll函数,在函数中把deep加1
                    addOtherDll(strPading, Convert.ToInt32(row["CategoryID"]), datatable, deep + 1, ddl);
                }
            }
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  • 原文地址:https://www.cnblogs.com/linyijia/p/3988849.html
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