ValidateBox控件使用Ajax改进

　　之前的ValidateBox控件单击更换图片时，整个页面都要刷新，所以想使用Ajax来试试可不可以改进。经过一试，Ajax还真管用！

　　AjaxComm.js代码：

// ********************************************************
// AjaxComm 1.1 for Asp.Net
// Designed by Faib Studio.
// Copyright 2007
// Email faib920@126.com or QQ 55570729
// ********************************************************
function AjaxComm()
{
    this.xmlHttp = null;
    var clsids = ["Msxml2.XMLHTTP.6.0","Msxml2.XMLHTTP.5.0","Msxml2.XMLHTTP.4.0","Msxml2.XMLHTTP.3.0","Msxml2.XMLHTTP.2.6","Microsoft.XMLHTTP.1.0","Microsoft.XMLHTTP.1","Microsoft.XMLHTTP"];

    for(var i=0; i<clsids.length && this.xmlHttp == null; i++)
    {
        try{
            this.xmlHttp = new ActiveXObject(clsids[i]);
        } catch(ex) {}
    }
}

AjaxComm.prototype.open = function (metohod, url)
{
    if(this.xmlHttp)
    {
        if(this.xmlHttp.readyState == 4 || this.xmlHttp.readyState == 0 )
        {
            var oThis = this;
            this.xmlHttp.open(metohod, url);
            this.xmlHttp.onreadystatechange = function(){ oThis.readyStateChange(); };
            this.xmlHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
            this.xmlHttp.send(null);
        }
    }
}

AjaxComm.prototype.abortCallBack = function()
{
  if(this.xmlHttp)this.xmlHttp.abort();
}
 
AjaxComm.prototype.onLoading = function()
{
}
 
AjaxComm.prototype.onLoaded = function()
{
}
 
AjaxComm.prototype.onInteractive = function()
{
}
 
AjaxComm.prototype.onComplete = function(responseText, responseXml)
{
}
 
AjaxComm.prototype.onAbort = function()
{
}
 
AjaxComm.prototype.onError = function(status, statusText)
{
}

AjaxComm.prototype.readyStateChange = function ()
{
  if( this.xmlHttp.readyState == 1 )
  {
    this.onLoading();
  }
  else if( this.xmlHttp.readyState == 2 )
  {
   this.onLoaded();
  }
  else if( this.xmlHttp.readyState == 3 )
  {
   this.onInteractive();
  }
  else if( this.xmlHttp.readyState == 4 )
  {
   if( this.xmlHttp.status == 0 )
      this.onAbort();
    else if( this.xmlHttp.status == 200 && this.xmlHttp.statusText == "OK" )
      this.onComplete(this.xmlHttp.responseText, this.xmlHttp.responseXML);
    else
      this.onError(this.xmlHttp.status, this.xmlHttp.statusText, this.xmlHttp.responseText);   
  }
}

　　ValidateBox的改进：

        private bool m_xx = false;

        protected override void OnInit(EventArgs e)
        {
            //注册一个js文件到缓存中
            Util.RegisterCacheFile(Page, "AjaxComm", "ajaxcomm.fbs.ashx", "Resource.AjaxComm.js");//对应到AjaxComm.js
            //输出控件初始化脚本
            Util.RegisterStartupScript(Page, "ValidateBox", @"
<script language=""javascript"" type=""text/javascript"">
function ValidateBox_Change(url)
{
    var ajax = new AjaxComm();
    ajax.onComplete = function (rText)
    {
        var v = rText.split(';');
        var val = event.srcElement;
        var src = val.src;
        src = src.substr(0, src.indexOf('?'));
        val.src = src + '?' + v[0];
        if(v.length > 1)
        {
            val.text = v[1];
            val.value = v[1].toLowerCase();
        }
    }
    ajax.open(""GET"", url);
}
</script>
");
            base.OnInit (e);
        }

        protected override void OnUnload(EventArgs e)
        {
            if(m_ValidateKey != null && m_ValidateKey != "" && !m_xx)
            {
                if(ViewState["Text"] != null)
                {
                    switch(m_ReturnStyle)
                    {
                        case ValidateStyle.Session:
                            Context.Session[m_ValidateKey] = ViewState["Text"].ToString();
                            break;
                        case ValidateStyle.Cookie:
                            Context.Response.Cookies[m_ValidateKey].Value = ViewState["Text"].ToString();
                            break;
                        case ValidateStyle.Cache:
                            Context.Cache[m_ValidateKey] = ViewState["Text"].ToString();
                            break;
                    }
                }
            }
            base.OnUnload (e);
        }

        protected override void OnLoad(EventArgs e)
        {
            string strCode = GetValidateCode();
            ViewState["Text"] = strCode;
            string cacheid = BuildImage();
            if(Page.Request.QueryString["GetValidateNewCode"] == this.ClientID)
            {
                Page.Response.Clear();
                if(m_ReturnStyle == ValidateStyle.Client)
                {
                    Page.Response.Write(cacheid + ";" + strCode);
                }
                else
                {
                    Page.Response.Write(cacheid);
                }
                Page.Response.End();
            }
            else if(Page.Request.QueryString["GetValidateNewCode"] != null)
            {
                m_xx = true;
            }

            if(m_ReturnStyle == ValidateStyle.Client)
            {
                this.Attributes.Add("Text", this.Text);
                this.Attributes.Add("value", this.Text.ToLower());
            }
            this.Style.Add("cursor", "hand");
            this.Attributes.Add("onclick", "ValidateBox_Change('" + Page.Request.FilePath + "?GetValidateNewCode=" + this.ClientID + "');");
            base.OnLoad(e);
        }