Protected override bool OnBubbleEvent(object source,EventArgs e){

bool handled=false;

if(e is CommandEventArgs){

CommandEventArgs ce=(CommandEventArgs)e;

If(ce.CommandName="Login"){

OnLogin(EventArgs.Empty);

Handled=true;

}

}

}

那么我怎么知道OnBubbleEvent被初始化呢。如何把一个button事件上上传到顶层事件

呢。引发事件On方法中调用RaiseBubbleEvent方法。

在button中OnCommand的内部实现。

protected virtual void OnCommand(CommandEventArgs e)

{

CommandEventHandler handler = (CommandEventHandler) base.Events[EventCommand];

if (handler != null)

{

handler(this, e);

}

base.RaiseBubbleEvent(this, e); //这里冒泡事件传给顶层事件。

}

而我们知道RaiseBubbleEvent调用了OnBubbleEvent方法（参见前面）。。然后我们就去重写了OnBubbleEvnet 方法，让它去处理我们的逻辑，满足一个条件后。返回true;

(四) 实现事件冒泡(事件上传)的步骤。

只要在自定义控件中，重写OnBubbleEvent方法，就能实现事件冒泡。因为在其子控件内部有一个OnCommand方法，它调用了RaiseBubbleEvent方法。而RaiseBubbleEvent调用了OnBubbleEvent方法。

示例：

protected override bool OnBubbleEvent(object sender,EventArgs e){
　bool handled = false;
　if(e is CommandEventArgs) {
　　CommandEventArgs ce = (CommandEventArgs)e;
　　if(ce.CommandName == "ButtonClick") {
　　　OnButtonClick(EventArgs.Empty);
　　　handled =true;
　　}
　}
　return handled;
}
本节用到的示例控件代码：

示例代码
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.ComponentModel.Design;
using System.ComponentModel;
/**////

public class Class2 : WebControl,INamingContainer
{

private Button _button;
private TextBox _nameTextBox;
private Label _nameLabel;
private Label _passwordLabel;
private TextBox _passwordText;
private RequiredFieldValidator _nameValidator;
private RequiredFieldValidator _passwordValidtor;
private static readonly object EventLogon=new object();
override properties#region override properties

public override ControlCollection Controls
{
get {

EnsureChildControls();
return base.Controls;
}
}

#endregion override properties
prorerties list#region prorerties list
[Bindable(true),Category("Appearance"),DefaultValue(""),Description("The text to display on the button")]
public string ButtonText
{
get{
EnsureChildControls();
return _button.Text;
}
set{
EnsureChildControls();
_button.Text=value;
}
}
[Bindable(true),Category("default"),DefaultValue(""),Description("the user name")]
public string Name{

get{
EnsureChildControls();
return _nameTextBox.Text;

}
set{
EnsureChildControls();
_nameTextBox.Text=value;
}
}
[Bindable(true),Category("Apearance"),DefaultValue(""),Description("Error Message of the validator used for the Name")]
public string NameErrorMessage{

get{

EnsureChildControls();
return _nameValidator.ErrorMessage;
}
set{
EnsureChildControls();
_nameValidator.ErrorMessage=value;
_nameValidator.ToolTip=value;
}
}
[Bindable(true),Category("Apperance"),DefaultValue(""),Description("the text for the name Label")]
public string NameLabel
{
get{
EnsureChildControls();
return _nameLabel.Text;
}
set{
EnsureChildControls();
_nameLabel.Text=value;
}
}
[Bindable(true),DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public string Password
{

get{
EnsureChildControls();
return _passwordText.Text;

}
}
[Bindable(true),Category("Appearance"),DefaultValue(""),Description("Error Message of the validator used for the Password")]
public string PasswordErrorMessage
{
get{
EnsureChildControls();
return _passwordValidtor.ErrorMessage;
}
set{
EnsureChildControls();
_passwordValidtor.ErrorMessage=value;
_passwordValidtor.ToolTip=value;
}
}
[Bindable(true),Category("Appearance"),DefaultValue(""),Description("the text for the password label")]
public string PasswordLabel
{
get{

EnsureChildControls();
return _passwordLabel.Text;
}
set{

EnsureChildControls();
_passwordLabel.Text=value;
}
}
#endregion

events#region events
[Category("Action"),Description("Raised when the user chicks the login button")]
public event EventHandler Logon
{
add{

Events.AddHandler(EventLogon,value);
}
remove{
Events.RemoveHandler(EventLogon,value);
}
}
public virtual void OnLogon(EventArgs e){

EventHandler logonHandler=(EventHandler)Events[EventLogon];
if(logonHandler !=null)
{
logonHandler(this,e);
}
}
#endregion

Event bubbling#region Event bubbling
//the use of event bubbling in this seenario is somewhat contrived;
//we have implemented it mainly for demostration purposes
//in this case you could instead
//raise the Logon event from an event handler wired to the
//click event or to the command event of the button control
protected override bool OnBubbleEvent(object source, EventArgs e)
{
bool handled=false;
if(e is CommandEventArgs)
{
CommandEventArgs ce=(CommandEventArgs)e;
if(ce.CommandName=="Logon")
{
OnLogon(EventArgs.Empty);
handled=true;
}
}
return handled;
}
#endregion
override methods#region override methods
protected override void CreateChildControls()
{

Controls.Clear();
_nameLabel=new Label();
_nameTextBox=new TextBox();
_nameTextBox.ID="nameTextBox";
_nameValidator=new RequiredFieldValidator();
_nameValidator.ID="validator1";
_nameValidator.ControlToValidate=_nameTextBox.ID;
_nameValidator.Text="*";
_nameValidator.Display=ValidatorDisplay.Static;
_passwordLabel=new Label();

_passwordText=new TextBox();
_passwordText.TextMode=TextBoxMode.Password;
_passwordText.ID="passwordTextBox";
_passwordValidtor=new RequiredFieldValidator();
_passwordValidtor.ID="validator2";
_passwordValidtor.ControlToValidate=_passwordText.ID;
_passwordValidtor.Text="*";
_passwordValidtor.Display=ValidatorDisplay.Static;

_button=new Button();
_button.ID="button1";
_button.CommandName="Logon";
this.Controls.Add(_nameLabel);
this.Controls.Add(_nameTextBox);
this.Controls.Add(_nameValidator);
this.Controls.Add(_passwordLabel);
this.Controls.Add(_passwordText);
this.Controls.Add(_passwordValidtor);
this.Controls.Add(_button);

base.CreateChildControls();
}
#endregion
protected override void Render(HtmlTextWriter writer)
{

AddAttributesToRender(writer);
writer.AddAttribute(HtmlTextWriterAttribute.Cellpadding,"1",false);
writer.AddAttribute(HtmlTextWriterAttribute.Border, "1", false);
writer.RenderBeginTag(HtmlTextWriterTag.Table);
writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
_nameLabel.RenderControl(writer);
writer.RenderEndTag();// TD
writer.RenderBeginTag(HtmlTextWriterTag.Td);
_nameTextBox.RenderControl(writer);
_nameValidator.RenderControl(writer);
writer.RenderEndTag();//TD

writer.RenderEndTag();//TR

writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.RenderBeginTag(HtmlTextWriterTag.Td);
_passwordLabel.RenderControl(writer);
writer.RenderEndTag();//TD
writer.RenderBeginTag(HtmlTextWriterTag.Td);
_passwordText.RenderControl(writer);

_passwordValidtor.RenderControl(writer);

writer.RenderEndTag();//TD

writer.RenderEndTag();//tr

writer.RenderBeginTag(HtmlTextWriterTag.Tr);
writer.AddAttribute(HtmlTextWriterAttribute.Colspan,"2");
writer.AddAttribute(HtmlTextWriterAttribute.Align,"center");
writer.RenderBeginTag(HtmlTextWriterTag.Td);

_button.RenderControl(writer);
writer.RenderEndTag();//td
writer.RenderBeginTag(HtmlTextWriterTag.Td);
// writer.Write("&nbsp");
writer.RenderEndTag();//td
writer.RenderEndTag();//tr
writer.RenderEndTag();//Table
// base.Render(writer);
}
public Class2()
{
//
// TOD 在此处添加构造函数逻辑
//
}
}
}