問題：
Datalist1顯示say這個表的數據
然后想在Datalist1中嵌套一個Datalist2用於顯示對應的評論
表2的 sayID對應表1的id，若表2中找不到對應sayId則在對應的Datalist1中不顯示Datalist2.
難點在於如何達到“林夏”的說說下面只顯示“黃磊”、“葉偉信”的評論，“韓寒”的下面只顯示“程程”的評論。（林夏的id是3，所以查詢對應的表2中sayId為3的行）。
代碼
前台代碼：
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title></title> <link href="Content/bootstrap.css" rel="stylesheet" /> </head> <body> <form id="form1" runat="server"> <h2 style="text-align:center;">評論列表</h2> <div align="center" style="margin-top:20px;"> <asp:DataList ID="DataList1" runat="server" OnItemDataBound="DataList1_ItemDataBound" Width="50%" CssClass="table table-bordered" CellPadding="0" CellSpacing="0"> <ItemTemplate> <div> 來自<%# Eval("place") %>的<%# Eval("username") %>於<%# Eval("date") %>發表 </div> <div> <%# Eval("text") %> </div> <asp:DataList ID="DataList2" runat="server" Width="100%"> <ItemTemplate> <div style="border: 1px dashed black; margin: 1px;"> <div> <%#Eval("username") %>的評論<%#Eval("date") %> </div> <div>評論內容：<%#Eval("text") %> </div> </div> </ItemTemplate> </asp:DataList> </ItemTemplate> </asp:DataList> </div> </form> </body> </html>
后台cs：
protected void Page_Load(object sender, EventArgs e) { if (!Page.IsPostBack) { this.DataList1.DataSource = Data(); this.DataList1.DataBind(); } } public DataSet Data() { DataSet ds = new DataSet(); DataTable dtParent = new DataTable(); dtParent.Columns.Add("id", typeof(int)); dtParent.Columns.Add("username", typeof(string)); dtParent.Columns.Add("text", typeof(string)); dtParent.Columns.Add("date", typeof(string)); dtParent.Columns.Add("place", typeof(string)); dtParent.Rows.Add(1, "摩根", "這個...", "2014.6", "倫敦"); dtParent.Rows.Add(2, "韓寒", "潮流...", "2015.7", "湖南"); dtParent.Rows.Add(3, "林夏", "歲月...", "2016.2", "小城"); dtParent.Rows.Add(4, "王菲", "我會...", "2015.9", "香港"); dtParent.Rows.Add(5, "郭敬明", "我們...", "2015.1", "上海"); DataTable dtChild = new DataTable(); dtChild.Columns.Add("id", typeof(int)); dtChild.Columns.Add("sayId", typeof(int)); dtChild.Columns.Add("username", typeof(string)); dtChild.Columns.Add("text", typeof(string)); dtChild.Columns.Add("date", typeof(string)); dtChild.Rows.Add(1, 3, "黃磊", "我是第一個評說", "2016.6.17 13:06:12"); dtChild.Rows.Add(3, 3, "葉偉信", "評論林夏的說", "2016.6.17 12:26:43"); dtChild.Rows.Add(4, 2, "程程", "我評論韓寒", "2015.3.1 15:20:10"); ds.Tables.AddRange(new DataTable[] { dtParent, dtChild }); DataRelation dr = new DataRelation("relation", dtParent.Columns["id"], dtChild.Columns["sayId"]); ds.Relations.Add(dr); dtParent = ds.Relations["relation"].ParentTable; dtChild = ds.Relations["relation"].ChildTable; return ds; } protected void DataList1_ItemDataBound(object sender, DataListItemEventArgs e) { if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { DataList dataList = e.Item.FindControl("DataList2") as DataList; DataRowView rowv = (DataRowView)e.Item.DataItem; DataRow[] rows = Data().Tables[1].Select("sayId='" + rowv["id"].ToString() + "'"); DataTable dt = Data().Tables[1].Clone(); foreach (DataRow dr in rows) { dt.ImportRow(dr); } dataList.DataSource = dt; dataList.DataBind(); } }
后台代碼中數據源部分可以用ado.net查詢數據庫方式替換。
效果圖：
