How to sanitize input and prevent XSS attack

Question

I am planning to use CKEDITOR at my asp.net application.

But i see that they don't prevent any way to prevent XSS attack at server side.

So how can i prevent XSS attack ? How can i sanitize input ?

What is the most effective sanitizer for asp.net c# ?

So i am basically looking for a decent solution to sanitize CKEDITOR input and display it back to the users safely. Thank you.

<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent" runat="Server">
  <script src="ckeditor/ckeditor.js"></script>
</asp:Content>

<asp:TextBox ID="ckEditor" TextMode="MultiLine" runat="server" ClientIDMode="Static">
</asp:TextBox>

<script type="text/javascript">
    CKEDITOR.replace('ckEditor');
</script>

Thank you