解决方案我目前正在使用：

我创建了一个辅助类：

 使用System.Web.UI; 
 using System.Web.UI.WebControls; 

 namespace BusinessLogic.Helper 
 {
 public class CssAdder 
 {
 public static void AddCss（string path，page page）
 {
 Literal cssFile = new Literal（）{Text = @< link href =+ page.ResolveUrl（path）+ @type =text / css =stylesheet /> }; 
 page.Header.Controls.Add（cssFile）; 
} 
} 
} 
 

这个帮助类，我所要做的是：

  CssAdder.AddCss（〜/ Resources / MainMaster / MainDesign.css，this.Page）; 
 CssAdder.AddCss（〜/ Resources / Styles / MainMaster / MainLayout.css，this.Page）; 
 CssAdder.AddCss（〜/ Resources / Styles / Controls / RightMainMenu.css，this.Page）; 
 // ... 
 

所以我可以根据需要添加一行

它希望它有帮助。

它也适用于母版页和内容页面的关系。 p>

PS：我不知道这个和其他解决方案之间的性能差异，但它看起来更优雅，更容易消费。如果你知道更好的方法，请让我知道。谢谢...

I want to add StyleSheets programmatically in the head section but one of the examples I saw seemed to need to many lines of code to add just one style sheet even though I may need a lot:

Example Code:

HtmlLink css = new HtmlLink();
css.Href = "css/fancyforms.css";
css.Attributes["rel"] = "stylesheet";
css.Attributes["type"] = "text/css";
css.Attributes["media"] = "all";
Page.Header.Controls.Add(css);

I also use Page.Header.RenderControl() method but it didn't work either. Object null something error was thrown.

I also used Page.Header.InnerHtml and InnerText += "<link .... "/> things but they threw the Literal error which is I think common error.

I used this code :

List<Literal> cssFiles = new List<Literal>();
cssFiles.Add(new Literal() { Text = @"<link href=""" +   ResolveUrl("~/Resources/Styles/MainMaster/MainDesign.css") + @""" type=""text/css"" rel=""stylesheet"" />" });
cssFiles.Add(new Literal() { Text = @"<link href=""" + ResolveUrl("~/Resources/Styles/MainMaster/MainLayout.css") + @""" type=""text/css"" rel=""stylesheet"" />" });
AddStyleRange(cssFiles);

private void AddStyleRange(List<Literal> cssFiles)
{
   foreach (Literal item in cssFiles)
   {
     this.Header.Controls.Add(item);
   }
}

It worked at first but when I change the pages it stopped working.

I am using Master Page and I am writing these codes on Master.cs file and also some people recommended to use this.Header instead of Page.Header but when I built it throws an error which says I cannot declare that like this.

It shouldn't be that hard to add many styles.

It is getting complicated.

Okay, here is the solution I am currently using :

I created a helper class :

using System.Web.UI;
using System.Web.UI.WebControls;

namespace BusinessLogic.Helper
{
    public class CssAdder
    {
        public static void AddCss(string path, Page page)
        {
            Literal cssFile = new Literal() { Text = @"<link href=""" + page.ResolveUrl(path) + @""" type=""text/css"" rel=""stylesheet"" />" };
            page.Header.Controls.Add(cssFile);
        }
    }
}

and then through this helper class, all I have to do is :

CssAdder.AddCss("~/Resources/Styles/MainMaster/MainDesign.css", this.Page);
CssAdder.AddCss("~/Resources/Styles/MainMaster/MainLayout.css", this.Page);
CssAdder.AddCss("~/Resources/Styles/Controls/RightMainMenu.css", this.Page);
//...

So I can add as much as I want with one line of simple code.

It also works with Masterpage and content page relationships.

Hope it helps.

P.S: I don't know the performance difference between this and other solutions but it looks more elegant and easy to consume. If you know better ways, please let me know. Thanks...