大家可能都用过Asp.net中的DropDownList控件，该控件有一个Items的集合属性，用于设置组合框的下拉选项。这种体贴的做法让用户倍感温馨，现在，我们也发挥一下自己的的才智，创建一个相同功能的属性。
我们将要创建的控件叫WebPanel，该控件用于网站导航，并且可以收缩，外观如下：
第一个图是未收缩的效果，第二个是收缩后的效果，虽然不炫，但是足可以说明问题了。
接下来再看一幅图：
这里，就是Collection属性的编辑器，今天我们就围绕这种效果展开话题。
在上面的Collection属性的编辑器中，主要分成两个部分，左边的部分是对象的集合，右边部分是选定对象的属性，我们可以对每个属性进行设置赋值。
首先，我们定义一个类：StringItem，该类有两个自定义属性：Text用于显示的文本，HyperText是导航的超链接。
using System;
using System.Web.UI;
namespace NSWebPanel
{
/// <summary>
/// StringItem 的摘要说明。
/// </summary>
///
public class StringItem : System.Web.UI.Control , IStateManager
{
private string _Text;
private string _HyperText;
public StringItem()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
public string Text
{
set
{
_Text = value;
}
get
{
return _Text;
}
}
public string HyperText
{
set
{
_HyperText = value;
}
get
{
return _HyperText;
}
}
#region IStateManager 成员
void IStateManager.TrackViewState()
{
base.TrackViewState();
}
bool IStateManager.IsTrackingViewState
{
get
{
return base.IsTrackingViewState;
}
}
object IStateManager.SaveViewState()
{
return base.SaveViewState();
}
void IStateManager.LoadViewState(object state)
{
base.LoadViewState(state);
}
#endregion
}
}
然后，再创建一个用于存放多个StringItem对象的类：StringItems，需要注意的是：该类要继承CollectionBase，这样才能使用默认的Collection属性编辑器。
using System;
using System.Collections;
using System.Web.UI;
namespace NSWebPanel
{
/// <summary>
/// StringItems 的摘要说明。
/// </summary>
public class StringItems : CollectionBase , IStateManager
{
private bool marked;
public StringItems() : base()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
private void Initialize()
{
marked = false;
}
public StringItem this[int index]
{
get
{
return (StringItem)base.List[index];
}
set
{
List[index] = value;
}
}
public void Add(StringItem aItem)
{
base.List.Add(aItem);
}
public void Remove(int index)
{
if(index < base.Count - 1 && index > 0 )
{
base.List.RemoveAt(index);
}
}
#region IStateManager 成员
void IStateManager.TrackViewState()
{
for(int i = 0 ; i < base.List.Count; i ++)
{
((IStateManager)base.List[i]).TrackViewState();
}
}
bool IStateManager.IsTrackingViewState
{
get
{
return marked;
}
}
object IStateManager.SaveViewState()
{
object[] iState = new object[base.List.Count];
for(int i = 0 ; i < base.List.Count; i ++)
{
iState[i] = ((IStateManager)base.List[i]).SaveViewState();
}
return iState;
}
void IStateManager.LoadViewState(object state)
{
if(state != null)
{
object[] viewState = (object[])state;
for(int i = 0 ; i < viewState.Length ; i ++)
{
((IStateManager)List[i]).LoadViewState(viewState[i]);
}
}
}
#endregion
}
}
最后，新建一个WEB控件库，名称为：NSWebPanel，以下是源代码：
using System;
using System.Web.UI;
using System.Collections;
using System.Web.UI.WebControls;
using System.ComponentModel;
namespace NSWebPanel
{
/// <summary>
/// WebCustomControl1 的摘要说明。
/// </summary>
public class WebCustomControl1 : System.Web.UI.WebControls.WebControl,INamingContainer,IStateManager
{
private const string SCRIPT = "<table id='t' border='1' width='228' height='145' bordercolor='#000000' cellspacing='0' cellpadding='0' bordercolorlight='#000000' bordercolordark='#FFFFFF'>\n" +
"<tr>\n" +
"<td width='228' height='20'>\n" +
"<table border='0' width='100%' cellpadding='0' cellspacing='0'>\n" +
"<tr>\n" +
"<td width='10%' bgcolor='#CCCCFF' id='sign' onmousedown='Shink()' align='center' style='cursor: hand; font-family: Webdings'>5</td>\n" +
"<td width='90%' style='font-size:14px'>\n" +
"<p align='center'>{0}</td>\n" +
"</tr>\n" +
"</table>\n" +
"</td>\n" +
"</tr>\n" +
"<tr id='downBlock'>\n" +
"<td width='228' height='113'>\n" +
"<table border='0' cellpadding='0' cellspacing='0' width='100%' height='106' style='font-size:14px'>\n" +
"<tr>\n" +
"<td width='100%' align='center' height='21' id='tr1'><a target='_blank' href='{6}'>{1}</a></td>\n" +
"</tr>\n" +
"<tr>\n" +
"<td width='100%' align='center' height='21' id='tr2'><a target='_blank' href='{7}'>{2}</a></td>\n" +
"</tr>\n" +
"<tr>\n" +
"<td width='100%' align='center' height='21' id='tr3'><a target='_blank' href='{8}'>{3}</a></td>\n" +
"</tr>\n" +
"<tr>\n" +
"<td width='100%' align='center' height='21' id='tr4'><a target='_blank' href='{9}'>{4}</a></td>\n" +
"</tr>\n" +
"<tr>\n" +
"<td width='100%' align='center' height='22' id='tr5'><a target='_blank' href='{10}'>{5}</a></td>\n" +
"</tr>\n" +
"</table>\n" +
"</td>\n" +
"</tr>\n" +
"</table>";
private const string JAVASCRIPT = "<script language='javascript'>\n" +
"var flag = true;\n" +
"function Shink()\n" +
"{\n" +
"if(flag) \n" +
"{\n" +
"document.all.downBlock.style.display = 'none';\n" +
"document.all.sign.innerText = '6';\n" +
"document.all.t.height = 20;\n" +
"} \n" +
"else\n" +
"{\n" +
"document.all.downBlock.style.display = 'block';\n" +
"document.all.sign.innerText = '5';\n" +
"}\n" +
"flag = !flag;\n" +
"}\n" +
"</script>\n";
private StringItems _Strings;
//注意下面红色的部分，一定要写哦
[
PersistenceMode(PersistenceMode.InnerProperty),
DesignerSerializationVisibility(DesignerSerializationVisibility.Content)
]
public StringItems Strings
{
get
{
if(_Strings == null)
_Strings = new StringItems();
return _Strings;
}
}
private string _Caption;
public string Caption
{
get
{
return _Caption;
}
set
{
_Caption = value;
}
}
#region 事件
private static object _FieldEvent = null;
public event System.EventHandler ProcessEvent
{
add
{
Events.AddHandler(_FieldEvent,value);
}
remove
{
Events.RemoveHandler(_FieldEvent,value);
}
}
#endregion
public void Execute()
{
EventHandler hander = (EventHandler)Events[_FieldEvent];
if(hander != null)
{
hander(this,null);
}
}
public override void RenderBeginTag(HtmlTextWriter writer)
{
base.RenderBeginTag (writer);
System.Text.StringBuilder str = new System.Text.StringBuilder();
str.AppendFormat(SCRIPT,this.Caption,_Strings[0].Text,_Strings[1].Text,_Strings[2].Text,_Strings[3].Text,_Strings[4].Text,_Strings[0].HyperText,_Strings[1].HyperText,_Strings[2].HyperText,_Strings[3].HyperText,_Strings[4].HyperText);
writer.WriteLine(str.ToString());
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender (e);
if(!Page.IsClientScriptBlockRegistered("13C165F4-DB2E-4484-AB1B-5B1F32C8FC8B"))
{
Page.RegisterClientScriptBlock("13C165F4-DB2E-4484-AB1B-5B1F32C8FC8B",JAVASCRIPT);
}
}
public override string ClientID
{
get
{
return base.ClientID + "LZH";
}
}
protected override void AddAttributesToRender(HtmlTextWriter writer)
{
base.AddAttributesToRender (writer);
writer.AddStyleAttribute("font-size","14px");
}
protected override HtmlTextWriterTag TagKey
{
get
{
return HtmlTextWriterTag.Div;
}
}
#region IStateManager 成员
void IStateManager.TrackViewState()
{
base.TrackViewState();
}
bool IStateManager.IsTrackingViewState
{
get
{
// TODO: 添加 WebCustomControl1.IsTrackingViewState getter 实现
return false;
}
}
object IStateManager.SaveViewState()
{
// TODO: 添加 WebCustomControl1.SaveViewState 实现
return null;
}
void IStateManager.LoadViewState(object state)
{
// TODO: 添加 WebCustomControl1.LoadViewState 实现
}
#endregion
}
}
原文：http://blog.csdn.net/lizanhong/archive/2004/10/16/138642.aspx