Question

I am trying to change the css class attribute that has been present on the site.master page at run time and I cant really get any head way I have so far tired

mainContainer.Attributes.Add("style", "background-image('myImage.png')");

AND

mainContainer.Attributes.Add("class", "className");

BUT non of these let me change the css of the master file at run time. i am using asp.net using c#

this is the code on the master page

 <div class="main">

            <asp:ContentPlaceHolder ID="MainContent" runat="server"/>


        </div>

Answer 1

ContentPlaceHolder is element wich won’t be existed in output html code. It only defines a region. You can try to change div with class “main”. Just add runat=”server” and id attributes and access from the code.

<div id="MainDiv" class="main" runat="server">

and then

MainDiv.Attributes.Add...