URL重寫給 asp.net Ajax帶來的問題

在使用了URL重寫的頁面，我們為了保證使用者進行PostBack後頁面的URL仍然是,我們原先展現給使用者的連結，比如是list_1.html而不是list.aspx?page=1

我們需要使用app_browsers目錄，存放瀏覽器定義檔案，相關說明可以參考msdn：http://msdn2.microsoft.com/zh-cn/library/ms228122(vs.80).aspx

 

<!--可在 <windir>\Microsoft.NET\Framework\<ver>\CONFIG\Browsers 中找到現有的瀏覽器定義--><browsers>  <browser refID="Default">    <controlAdapters>      <adapter controlType="System.Web.UI.HtmlControls.HtmlForm"               adapterType="FormRewriterControlAdapter" />    </controlAdapters>  </browser></browsers>

 

 

代碼如下：

public class FormRewriterControlAdapter : System.Web.UI.Adapters.ControlAdapter    {        protected override void Render(HtmlTextWriter writer)        {            if (HttpContext.Current.Request.RawUrl.Contains(".html"))            {                base.Render(new RewriteFormHtmlTextWriter(writer));            }            else            {                base.Render(writer);            }        }    }    public class RewriteFormHtmlTextWriter : HtmlTextWriter    {        public RewriteFormHtmlTextWriter(Html32TextWriter writer)            : base(writer)        {            this.InnerWriter = writer.InnerWriter;        }        public RewriteFormHtmlTextWriter(System.IO.TextWriter writer)            : base(writer)        {            this.InnerWriter = writer;        }        public override void WriteAttribute(string name, string value, bool fEncode)        {            if (name == "action")            {                if (HttpContext.Current.Items["ActionAlreadyWritten"] == null)                {                    value = HttpContext.Current.Request.RawUrl;                    HttpContext.Current.Items["ActionAlreadyWritten"] = true;                }            }            base.WriteAttribute(name, value, fEncode);        }    }

以上代碼一直運行了很長時間，但是後來在使用asp.net Ajax是發現URL重寫後的頁面會出現錯誤，重新修改代碼，排除Asp.net Ajax請求進行處理，代碼如下：

public class FormRewriterControlAdapter : System.Web.UI.Adapters.ControlAdapter    {        protected override void Render(HtmlTextWriter writer)        {            if (HttpContext.Current.Request.RawUrl.Contains(".html"))            {                //取得asp.net Ajax請求標誌                var AsyncPost=HttpContext.Current.Request.Form["__ASYNCPOST"];                if (AsyncPost=="true") //判斷是否asp.net Ajax請求                {                    base.Render(writer);                }                else                {                    base.Render(new RewriteFormHtmlTextWriter(writer));                }            }            else            {                base.Render(writer);            }        }    }    public class RewriteFormHtmlTextWriter : HtmlTextWriter    {        public RewriteFormHtmlTextWriter(Html32TextWriter writer)            : base(writer)        {            this.InnerWriter = writer.InnerWriter;        }        public RewriteFormHtmlTextWriter(System.IO.TextWriter writer)            : base(writer)        {            this.InnerWriter = writer;        }        public override void WriteAttribute(string name, string value, bool fEncode)        {            if (name == "action")            {                if (HttpContext.Current.Items["ActionAlreadyWritten"] == null)                {                    value = HttpContext.Current.Request.RawUrl;                    HttpContext.Current.Items["ActionAlreadyWritten"] = true;                }            }            base.WriteAttribute(name, value, fEncode);        }    }

後又經過調試發現是RewriteFormHtmlTextWriter的構造器有問題，沒有包含htmlTextWriter類型的構造器，而使用了TextWriter類型構造器，導致頁面結構錯誤出現null報錯。再次調整代碼如下：

public class FormRewriterControlAdapter : System.Web.UI.Adapters.ControlAdapter    {        protected override void Render(HtmlTextWriter writer)        {            if (HttpContext.Current.Request.RawUrl.Contains(".html"))            {                //使用過濾掉asp.net Ajax請求的方式避免錯誤                //而後發現是RewriteFormHtmlTextWriter的構造器的問題，遂放棄方法                //var AsyncPost=HttpContext.Current.Request.Form["__ASYNCPOST"];                //if (AsyncPost=="true")                //{                //    base.Render(writer);                //}                //else                //{                //    base.Render(new RewriteFormHtmlTextWriter(writer));                //}                base.Render(new RewriteFormHtmlTextWriter(writer));            }            else            {                base.Render(writer);            }        }    }    public class RewriteFormHtmlTextWriter : HtmlTextWriter    {        //使用html 4.0方式的渲染器        public RewriteFormHtmlTextWriter(HtmlTextWriter writer)            : base(writer)        {            this.InnerWriter = writer.InnerWriter;        }        //使用html 3.2方式的渲染器，相容老瀏覽器        public RewriteFormHtmlTextWriter(Html32TextWriter writer)            : base(writer)        {            this.InnerWriter = writer.InnerWriter;        }        //其他方式瀏覽器，有可能引起null錯誤        public RewriteFormHtmlTextWriter(System.IO.TextWriter writer)            : base(writer)        {            this.InnerWriter = writer;        }        public override void WriteAttribute(string name, string value, bool fEncode)        {            if (name == "action")            {                if (HttpContext.Current.Items["ActionAlreadyWritten"] == null)                {                    value = HttpContext.Current.Request.RawUrl;                    HttpContext.Current.Items["ActionAlreadyWritten"] = true;                }            }            base.WriteAttribute(name, value, fEncode);        }    }

關於HtmlTextWriter和Html32TextWriter可以看一下這篇文章 http://www.cnblogs.com/Vegaslee/archive/2007/12/04/982723.html