change - Adding css class through aspx code behind

aspx change div class (4)

I am using aspx. If I have HTML as follows:

<div id="classMe"></div>

I am hoping to dynamically add a css class through the code behind file, ie on Page_Load. Is it possible?

Assuming your div has some CSS classes already...

<div id="classMe" CssClass="first"></div>

The following won't replace existing definitions:

ClassMe.CssClass += " second";

And if you are not sure until the very least moment...

string classes = ClassMe.CssClass;
ClassMe.CssClass += (classes == String.Empty) ? "second" : " second";

If you want to add attributes, including the class, you need to set runat="server" on the tag.

    <div id="classMe" runat="server"></div>

Then in the code-behind:

classMe.Attributes.Add("class", "some-class")


controlName.CssClass="CSS Class Name";


txtBank.CssClass = "csError";

BtnAdd.CssClass = "BtnCss";

BtnCss should be present in your Css File.

(reference of that Css File name should be added to the aspx if needed)