应用css <li> 标签，主页中的ASP.Net

Question

Hi all I would like to apply css for <li> tag which is in master page dynamically from code behind this is my design

<div id="primary_nav">
    <ul>
       <li class="left active" id="nav_discussion" runat="server">
           <a title="Go to Forums" href="">
               Forums
           </a>
       </li>
       <li class="left" id="nav_members" runat="server">
           <a title="Go to Member List" href="Members.aspx">
               Members
           </a>
       </li>
    </ul>
 </div>

In my content page I accessed <li> as follows

Control li = Page.Master.FindControl("nav_members");

But I am unable to apply the required css here can some one help me

Answer 1

In this case, your Control is of type HtmlGenericControl which does not contain a property for CssClass .

You will need to cast your control to type HtmlGenericControl. eg

System.Web.UI.HtmlControls.HtmlGenericControl li = (System.Web.UI.HtmlControls.HtmlGenericControl) this.Page.Master.FindControl("nav_members");

This will then give you two choices to apply the style to the element. You can either use the Style property or the Attributes property.

The Style property will allow you to add inline styling to the element eg:

li.Style.Add("Color", "Black");

This will render the element with:

style="color:red;"

Your other option is to use the Attributes property which will allow you to add the class .

li.Attributes.Add("class", "nameofyourclass");

Read more about the HtmlGenericControl

Answer 2

If you find the control then use following to add css

 Control li = Page.Master.FindControl("nav_members");
 li .Style.Add("float", "left");

If you want to override some property then you can use

  li .Style.Add("width", "100px !important");

etc.Here is a good link
What are the implications of using "!important" in CSS?

Here is a similar question
C# - How to change HTML elements attributes

Edit 1.

You need to cast it in a html generic control first

 HtmlGenericControl  li = (HtmlGenericControl)(Page.Master.FindControl("nav_members"));
 li .Style.Add("width", "100px !important");

Answer 3

尝试：

nav_members.Attributes.Add("class", value);