关于控件事件流程解决办法

关于控件事件流程
代码如下:
using   System;
using   System.Collections.Specialized;
using   System.Web.UI;
using   System.Web.UI.WebControls;
using   System.ComponentModel;

namespace   购物车
{
///   <summary>
///   WebCustomControl1   的摘要说明。
///   </summary>
public   enum   LoaderType{DetailLoader,CartLoader};
public   delegate   void   CartLoaderEventHandler(object   sender,CartLoaderEventArgs   e);

public   class   CartLoaderEventArgs:EventArgs
{
private   int   _itemCount;
private   string   _productNumber;

public   CartLoaderEventArgs(){}

public   CartLoaderEventArgs(string   ProductNumber)
{
_itemCount   =   0;
_productNumber   =   ProductNumber;
}

public   CartLoaderEventArgs(string   ProductNumber,int   NumberOfItems)
{
_itemCount   =   NumberOfItems;
_productNumber   =   ProductNumber;
}

public   string   ProductNumber
{
get{return   _productNumber;}
set{_productNumber   =   value;}
}

public   int   NumberOfItems
{
get{return   _itemCount;}
set{_itemCount   =   value;}
}

}

public   class   CartLoader   :   System.Web.UI.WebControls.WebControl,IPostBackDataHandler,IPostBackEventHandler
{
public   event   CartLoaderEventHandler   ItemAdded;
public   event   CartLoaderEventHandler   ItemUpdated;
public   event   CartLoaderEventHandler   ItemRemoved;

private   LoaderType   _location   =   LoaderType.DetailLoader;
private   string   _productID;
private   int   _itemCount;

public   LoaderType   Location
{
get{return   _location;}
set{_location   =   value;}
}
public   string   ProductID
{
get{return   _productID;}
set{_productID   =   value;}
}

public   int   ItemCount
{
get{return   _itemCount;}
set{_itemCount   =   value;}
}

protected   void   OnItemAdded()
{
if(ItemAdded   !=   null)
ItemAdded(this,new   CartLoaderEventArgs(_productID,_itemCount));
}

protected   void   OnItemUpdated()
{
if   (ItemUpdated   !=   null)
ItemUpdated(this,new   CartLoaderEventArgs(_productID,_itemCount));
}

protected   void   OnItemRemoved()
{
if   (ItemRemoved   !=   null)
ItemRemoved(this,new   CartLoaderEventArgs(_productID));
}
//加载文本框数据时引发
public   bool   LoadPostData(string   postDataKey,NameValueCollection   postData)
{
int   count   =   Int32.Parse(postData[postDataKey]);
if   (_itemCount   !=   count)
{
_itemCount   =   count;
return   true;
}
else
{
return   false;
}
}
//如果控件启动回送．也就是有一个按钮被单击．调用此方法
public   void   RaisePostDataChangedEvent()
{
OnItemUpdated();
}

public   void   RaisePostBackEvent(string   eventArgument)
{
if   (eventArgument   ==   "AddToCart ")

{
OnItemAdded();
_itemCount++;
}
else   if(eventArgument   ==   "RemoveFromCart ")
{
OnItemRemoved();
_itemCount   =   0;
}
}

protected   override   void   Render(HtmlTextWriter   output)
{
//如果控件处在详细说明模式，呈现一个按钮把它添加到购物车中
if   (_location   ==   LoaderType.DetailLoader)
{
output.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.GetPostBackEventReference(this, "AddToCart "));
output.AddAttribute(HtmlTextWriterAttribute.Style, "Display:inline;BORDER-RIGHT:gray   thin   outset;BORDER-TOP:gray   thin   outset;BORDER-LEFT:gray   thin   outset;CURSOR:hand;BORDER-BOTTOM:gray   thin   outset;FONT-FAMILY: 'ComicSans   MS ';BACKGROUND-COLOR:lightgrey ");
output.RenderBeginTag(HtmlTextWriterTag.Div);
output.Write( "Add   to   cart ");
output.RenderEndTag();
}
else//现在在购物车详细说明页面，因此显示两个按钮和一个文本框
{
output.AddAttribute(HtmlTextWriterAttribute.Width, "5 ");
output.AddAttribute(HtmlTextWriterAttribute.Name,this.UniqueID);
output.AddAttribute(HtmlTextWriterAttribute.Value,_itemCount.ToString());
output.RenderBeginTag(HtmlTextWriterTag.Input);
output.RenderEndTag();

//呈现删除按钮
output.AddAttribute(HtmlTextWriterAttribute.Style, "Display:inline;BORDER-RIGHT:gray   thin   outset;BORDER-TOP:gray   thin   outset;BORDER-LEFT:gray   thin   outset;CURSOR:hand;BORDER-BOTTOM:gray   thin   outset;FONT-FAMILY: 'ComicSans   MS ';BACKGROUND-COLOR:lightgrey ");
output.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.GetPostBackEventReference(this, "RemoveFromCart "));
output.RenderBeginTag(HtmlTextWriterTag.Div);
output.Write( "Remove ");
output.RenderEndTag();

//呈现更新按钮
output.AddAttribute(HtmlTextWriterAttribute.Style, "Display:inline;BORDER-RIGHT:gray   thin   outset;BORDER-TOP:gray   thin   outset;BORDER-LEFT:gray   thin   outset;CURSOR:hand;BORDER-BOTTOM:gray   thin   outset;FONT-FAMILY: 'ComicSans   MS ';BACKGROUND-COLOR:lightgrey ");
output.AddAttribute(HtmlTextWriterAttribute.Onclick,Page.GetPostBackEventReference(this, " "));
output.RenderBeginTag(HtmlTextWriterTag.Div);
output.Write( "Update ");
output.RenderEndTag();
}
}

protected   override   object   SaveViewState()
{
return   (object)_itemCount;
}

protected   override   void   LoadViewState(object   state)
{
_itemCount   =   (int)state;
}


}
}

当点击Add   to   Cart,Remove,Update会引发
LoadPostData(string   postDataKey,NameValueCollection   postData)方法
会进行判断原始数量是否用户刚输入数量是否相同．如果不同的话返回真．执行下列方法
public   void   RaisePostBackEvent(string   eventArgument)
{
if   (eventArgument   ==   "AddToCart ")
{
OnItemAdded();
_itemCount++;
}
else   if(eventArgument   ==   "RemoveFromCart ")
{
OnItemRemoved();
_itemCount   =   0;
}
}

但此方法
public   void   RaisePostDataChangedEvent()
{
OnItemUpdated();
}
当单击Update首先执行LoadPostData方法．会判断文本框内原始值是否等于用户输入的值．如果等于的话返回假．不会执行RaisePostBackEvent方法．而是执行
public   void   RaisePostDataChangedEvent()

{
OnItemUpdated();
}

这个方法．不知小弟理解的正确不正确．只是心里有点疑惑．或着哪位耐心看完这段程序后．给我讲一个完整的流程．THANK   YOU

[解决办法]
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