ASP.NET：在后面的代码中更改CSS链接href？

Question

I have an .ASPX page in which I want to change the CSS href in code behind. I searched for several tricks to do this but couldn't find anything that works as I intend.

HTML Markup:

<link id="linkCSS" runat="server" href='/css/1.css' rel="stylesheet" type="text/css" />

This is what I attempted in Code behind:

If (mobile)
{
    HtmlLink link = (HtmlLink)this.FindControl(linkCSS.UniqueID);
    link.Href = "/css/2.css";
}

But I'm getting the following exception:

Unable to cast object of type 'System.Web.UI.HtmlControls.HtmlGenericControl' to type 'System.Web.UI.HtmlControls.HtmlLink'.

Any ideas? Thanks.

Answer 1

Since you can't get and modify the control (although I believe it's possible) you can use placeholder to have more control over it. Like this:

<asp:PlaceHolder ID="headPlaceHolder" runat="server" />

And then in your server code:

HtmlLink link = new HtmlLink();
link.Href = "/css/2.css";
headPlaceHolder.Controls.Add(link);

See if it helps :)

Answer 2

There is no need to find css you can change it as follows.

If (mobile)
{
  linkCSS.Attributes["href"] = "~/css/2.css";
}

I've had reffered This Link.

Answer 3

You can use this code on your server side

HtmlGenericControl link = this.FindControl(linkCSS.UniqueID) as HtmlGenericControl;

link.Attributes["href"] = "css/2.css";