方法很简单。把代码放上来大家看看！
打了包成了个控件。下载地址：
下面是源码：
===================================
using System;
namespace HDControl
{
/// <summary>
/// Summary description for Loading.
/// </summary>
public class Loading
{
private System.Web.UI.Page Sender;
private string strImagePath;
public object Page
{
get
{
return Sender;
}
set
{
Sender = (System.Web.UI.Page)value;
}
}
public string ImageMapth
{
get
{
return strImagePath;
}
set
{
strImagePath = value;
}
}
public Loading()
{
//
}
public Loading( object sender )
{
Page = sender;
}
public Loading( object sender,string ImageMapth )
{
Page = sender;
this.strImagePath = ImageMapth;
}
/// <summary>
/// Load script to page
/// </summary>
public void Load()
{
if ( !this.Sender.IsClientScriptBlockRegistered( "startScript" ) )
{
this.Sender.RegisterClientScriptBlock( "startScript",this.Start() );
this.Sender.RegisterStartupScript( "endScript",this.End() );
}
}
/// <summary>
/// Script start.
/// </summary>
/// <returns></returns>
private string Start()
{
string strStyle = "BORDER-TOP-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-LEFT-STYLE: none; BORDER-BOTTOM-STYLE: none";
System.Text.StringBuilder strScript = new System.Text.StringBuilder();
strScript.Append( "<div id=\"loading\">" );
strScript.Append( "<table width=\"100%\" height=\"100%\" border=\"0\" cellpadding=\"0\" cellspacing=\"0\" style=\""+ strStyle + "\">" );
strScript.Append( "<tr style=\"" + strStyle + "\" ><td width=\"100%\" height=\"100%\" align=\"center\" valign=\"middle\" style=\"" + strStyle + "\">" );
strScript.Append( "<img src=\"" + this.ImageMapth + "\" border=\"0\">" );
strScript.Append( "</td></tr>" );
strScript.Append( "</table></div>" );
return strScript.ToString();
}
/// <summary>
/// Script end.
/// </summary>
/// <returns></returns>
private string End()
{
System.Text.StringBuilder strScript = new System.Text.StringBuilder();
strScript.Append( "<script language=\"javascript\">" );
strScript.Append( "window.document.getElementById(\"loading\").style.display = \"none\";" );
strScript.Append( "</script>" );
return strScript.ToString();
}
}
}
=========================
先在面页中
using HDControl;
调用方法（在Page_Load里）：
LoadingControl.Loading objLoad = new LoadingControl.Loading( this,"Images/loading.gif" );
objLoad.Load();
或：
LoadingControl.Loading objLoad = new LoadingControl.Loading( );
objLoad.Page = this;
objLoad.ImageMapth = "Images/loading.gif";
objLoad.Load();