代码 public partial class 递归2 : System.Web.UI.Page { public List<cmodel> list; protected void Page_Load(object sender, EventArgs e) { if (!IsPostBack) { rules r = new rules(); list = r.getlist();//读取数据库 this.rep.DataSource = list.Where(x => x.parentid == 0).ToList();//LINQ2OBJECT this.rep.DataBind(); } }
protected void rep_ItemDataBound(object sender, RepeaterItemEventArgs e) { if (e.Item.ItemType == ListItemType.Header) { Literal l = new Literal(); l.ID = "ul"; l.Text="<ul>"; e.Item.Controls.Add(l); } else if (e.Item.ItemType == ListItemType.Footer) { Literal l = new Literal(); l.ID = "ul2"; l.Text = "</ul>"; e.Item.Controls.Add(l); } else if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem) { int id = (int)DataBinder.Eval(e.Item.DataItem, "id"); Literal li1 = new Literal(); li1.ID = "li1"; li1.Text = "<li>"; e.Item.Controls.Add(li1);
Literal name = new Literal(); name.ID = "n"; name.Text = DataBinder.Eval(e.Item.DataItem, "classname").ToString(); e.Item.Controls.Add(name); List<cmodel> temp = list.Where(x => x.parentid == id).ToList();//LINQ2OBJECT if (temp.Count > 0) { Repeater r = new Repeater(); TemplateBuilder tb = new TemplateBuilder(); tb.AppendLiteralString(""); r.HeaderTemplate = tb; r.FooterTemplate = tb; r.ItemTemplate = tb; r.ItemDataBound += new RepeaterItemEventHandler(rep_ItemDataBound); //递归核心 r.DataSource = temp; r.DataBind(); e.Item.Controls.Add(r); } Literal li2 = new Literal(); li2.ID = "li2"; li2.Text = "</li>"; e.Item.Controls.Add(li2); } }
}
使用到的类:
代码 public class rules { DataClasses1DataContext dc = new DataClasses1DataContext();
public List<cmodel> getlist() { var q = from x in dc.ClassFJ where x.sort > 0 //用于控制显示隐藏 orderby x.sort //兼职排序功能 select new cmodel ( x.id, x.className, x.parentid ); return q.ToList<cmodel>(); } }
public class cmodel { public cmodel(int i,string n,int p) { id = i; classname = n; parentid = p; } public int id { get; set; } public string classname { get; set; } public int parentid { get; set; } }
----------------
1 null 根目录
2 1 一级a
3 2 二级a-1
4 2 二级a-2
5 1 一级b
6 5 二级b-1
7 6 三级b-1-1
8 5 二级b-2
...
层次1,ID=1980,上级ID=0 说明是顶层
层次2,ID=2542,上级ID=1980 说明他是 层次1的下层
层次3, ID=10045,上级ID=2542 说明他是 层次2的下层
1.可以用表达式字段存储绝对路径,系统会在insert,update时自行维护绝对路径;
2.绝对路径改成(或者在增加一个字段)ParentPath更好
详见:http://www.soaspx.com/dotnet/csharp/csharp_20101109_6358.html
数据库结构:
id(int) classname(string) parentid(int) sort(int用于显示与排序)
1 家居 0 1
2 家电 0 2
3 沙发 1 1
4 某... 3 1
...
10 ...红色 4 1
注:
parentid 父节点ID
sort 用于隐藏或显示 兼排序功能
前台:
<asp:Repeater ID="rep" runat="server" onitemdatabound="rep_ItemDataBound">
<HeaderTemplate></HeaderTemplate>
<ItemTemplate></ItemTemplate>
<FooterTemplate></FooterTemplate>
</asp:Repeater>
后台:
代码 public partial class 递归2 : System.Web.UI.Page
{
public List<cmodel> list;
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
rules r = new rules();
list = r.getlist();//读取数据库
this.rep.DataSource = list.Where(x => x.parentid == 0).ToList();//LINQ2OBJECT
this.rep.DataBind();
}
}
protected void rep_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Header)
{
Literal l = new Literal();
l.ID = "ul";
l.Text="<ul>";
e.Item.Controls.Add(l);
}
else if (e.Item.ItemType == ListItemType.Footer)
{
Literal l = new Literal();
l.ID = "ul2";
l.Text = "</ul>";
e.Item.Controls.Add(l);
}
else if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
int id = (int)DataBinder.Eval(e.Item.DataItem, "id");
Literal li1 = new Literal();
li1.ID = "li1";
li1.Text = "<li>";
e.Item.Controls.Add(li1);
Literal name = new Literal();
name.ID = "n";
name.Text = DataBinder.Eval(e.Item.DataItem, "classname").ToString();
e.Item.Controls.Add(name);
List<cmodel> temp = list.Where(x => x.parentid == id).ToList();//LINQ2OBJECT
if (temp.Count > 0)
{
Repeater r = new Repeater();
TemplateBuilder tb = new TemplateBuilder();
tb.AppendLiteralString("");
r.HeaderTemplate = tb;
r.FooterTemplate = tb;
r.ItemTemplate = tb;
r.ItemDataBound += new RepeaterItemEventHandler(rep_ItemDataBound); //递归核心
r.DataSource = temp;
r.DataBind();
e.Item.Controls.Add(r);
}
Literal li2 = new Literal();
li2.ID = "li2";
li2.Text = "</li>";
e.Item.Controls.Add(li2);
}
}
}
使用到的类:
代码 public class rules
{
DataClasses1DataContext dc = new DataClasses1DataContext();
public List<cmodel> getlist()
{
var q = from x in dc.ClassFJ
where x.sort > 0 //用于控制显示隐藏
orderby x.sort //兼职排序功能
select new cmodel
(
x.id,
x.className,
x.parentid
);
return q.ToList<cmodel>();
}
}
public class cmodel
{
public cmodel(int i,string n,int p)
{
id = i;
classname = n;
parentid = p;
}
public int id { get; set; }
public string classname { get; set; }
public int parentid { get; set; }
}
抛砖引玉,话不多讲。
但是考虑到效率问题,一旦数据量一多 以后递归量增多,会严重影响效率。
可以添加适当辅助字段,优化递归方式。