Question

也许我说这一切都错了（请告诉我，如果我的话），但我正在用一个看起来非常简单的概念的方式撞墙。

此渲染覆盖来自用户控件。

protected override void Render(HtmlTextWriter writer)
{
    string htmlAboutToBeRendered = writer.GetWhatHasBeenWrittenToTheWriterSoFar();

    // Do something nefarious, yet unrelated with htmlAboutToBeRendered
}

这似乎有一种明显的方法可以做到这一点，但我似乎无法找到它。

有人可以为我解释一下吗？

Answer 1

试试这个：

protected override void RenderContents(HtmlTextWriter output)  
{  
   StringBuilder sb = new StringBuilder();  
   HtmlTextWriter htw = new HtmlTextWriter(new System.IO.StringWriter(sb,   
   System.Globalization.CultureInfo.InvariantCulture));  
   foreach (Control ctrl in Controls)  
   {  
      ctrl.RenderControl(htw);  
   }  
  string strContents = sb.ToString();

}

Answer 2

您可以从HttpTextWriter派生并覆盖OnTagRender，OnAttributeRender和OnStyleRender方法，并在呈现时修改标记。 OnTagRender的MSDN文档显示了在呈现期间修改标记的示例：

http://msdn.microsoft.com/en-us/library/system.web.ui.htmltextwriter.ontagrender.aspx

Answer 3

使用relfection的替代方法：

private string GetString(HtmlTextWriter writer) 
{
   // the flags to see the internal properties of the writer
   System.Reflection.BindingFlags flags = System.Reflection.BindingFlags.Default;
   flags |= System.Reflection.BindingFlags.NonPublic;
   flags |= System.Reflection.BindingFlags.Instance;
   flags |= System.Reflection.BindingFlags.FlattenHierarchy;
   flags |= System.Reflection.BindingFlags.Public;

   // get the information about the internal TextWriter object
   System.Reflection.FieldInfo baseWriter = writer.GetType().GetField("writer", flags);

   // use that info to create a StringWriter
   System.IO.StringWriter reflectedWriter = (System.IO.StringWriter)baseWriter.GetValue(writer);

   // now we get a StringBuilder!
   StringBuilder builder = reflectedWriter.GetStringBuilder();

   return builder.ToString();
}

然后，使用字符串和StringBuilder重新创建HtmlTextWriter是一件简单的事。

这是使用我从EggheadCafe的conversation between Tom Spink and Rotsey获取的一些线索构建的

HtmlTextWriter到String - 我忽略了什么吗？

3 个答案: