本文介绍的菜单控件采用的css 和ul list来显示菜单，生成的html小，无需javascript支持，对大部分的浏览器都支持，除ie6要单独修改css也可以使其支持。
通过本文可以了解asp.net 控件的开发，及Composite设计模式的实际运用。
采用Composite设计模式设计菜单类：
MenuCompositeitem类
namespace Ruinet.Controls
{
[Serializable()]
public class MenuCompositeItem
{
private
List<MenuCompositeItem> _children = new List<MenuCompositeItem>();
private string _text;
private string _link;
private string _target;
/// <summary>
/// 菜单项
/// </summary>
/// <param
name="text">菜单名</param>
/// <param
name="link">链接</param>
public MenuCompositeItem(string text, string
link)
{
this._text = text;
this._link = link;
}
///
<summary>
/// 菜单项
/// </summary>
/// <param
name="text">菜单名</param>
/// <param
name="link">链接</param>
/// <param
name="target">跳转目标</param>
public MenuCompositeItem(string text,
string link, string target)
{
this._text = text;
this._link = link;
this._target = target;
}
/// <summary>
/// 设置或获取菜单名
/// </summary>
public string Text
{
get { return _text; }
set { _text = value; }
}
/// <summary>
/// 设置或获取链接
///
</summary>
public string Link
{
get { return _link; }
set
{ _link = value; }
}
/// <summary>
/// 跳转目标
///
</summary>
public string Target
{
get { return _target; }
set { _target=value; }
}
/// <summary>
/// 设置或获取子菜单
/// </summary>
public List<MenuCompositeItem> Children
{
get { return _children; }
set { _children = value; }
}
}
namespace Ruinet.Controls
{
[DefaultProperty("Menu")]
[ToolboxData("<{0}:MenuComposite
runat=server></{0}:MenuComposite>")]
public class MenuComposite :
WebControl
{
/// <summary>
/// 设置获取选择的菜单
///
</summary>
[Bindable(true)]
[DefaultValue("")]
[Localizable(true)]
public string SelectedMenuText
{
get
{
String s = (String)ViewState["SelectedMenuText"];
return ((s == null) ?
String.Empty : s);
}
set
{
ViewState["SelectedMenuText"] =
value;
}
}
/// <summary>
/// 获取和设置菜单项从ViewState
///
</summary>
[Bindable(true)]
[DefaultValue(null)]
[Localizable(true)]
public MenuCompositeItem MenuItems
{
get
{
return ViewState["MenuItems"] as MenuCompositeItem;
}
set
{
ViewState["MenuItems"] = value;
}
}
/// <summary>
/// 呈现菜单结构
/// </summary>
/// <param
name="output">HTML输出流</param>
protected override void
RenderContents(HtmlTextWriter output)
{
MenuCompositeItem root =
this.MenuItems;
output.Write(@"<div class=""navmenu"">");
output.Write(@" <ul>");
for (int i = 0; i <
root.Children.Count; i++)
{
RecursiveRender(output, root.Children[i]);
}
output.Write(@" </ul>");
output.Write(@"</div>");
}
/// <summary>
/// 递归输出菜单项
/// </summary>
///
<param name="output">HTML输出流</param>
/// <param
name="item">菜单项.</param>
/// <param name="depth">Indentation
depth.</param>
private void RecursiveRender(HtmlTextWriter output,
MenuCompositeItem item)
{
output.Write("<li>");
if
(string.IsNullOrEmpty(item.Target))//为空不设置跳转目标
{
output.Write(@"<a
href=""" + item.Link + @""">");
}
else
{
output.Write(@"<a
href=""" + item.Link + @""" target= """ + item.Target + @""">");
}
if
(item.Text == SelectedMenuText) //选中的菜单
{
output.Write(@"<span
class=""selected"">");
output.WriteLine(item.Text);
output.WriteLine("</span>");
}
else
{
output.Write(item.Text);
}
output.Write("</a>");
if
(item.Children.Count > 0)
{
output.WriteLine();
output.Write("<ul>");
for (int i = 0; i < item.Children.Count;
i++)
{
RecursiveRender(output, item.Children[i]);
}
output.Write("</ul>");
}
output.Write("</li>");
}
}
}
