Class
AsBool(), AsBool(true|false),AsDateTime(), AsDateTime(value),AsDecimal(), AsDecimal(value),AsInt(), AsInt(value),AsFloat(), AsFloat(value).

IsEmpty()

Returns true if the object or variable has no value.

if (Request["companyname"].IsEmpty()) {
   @:Company name is required.<br />
}

Request.Cookies[key]

Gets or sets the value of an HTTP cookie.

var cookieValue = Request.Cookies["myCookie"].Value;

Server.HtmlDecode(htmlText)

Decodes a string that is HTML encoded.

var htmlDecoded = Server.HtmlDecode("&lt;html&gt;");

Server.HtmlEncode(text)

Encodes a string for rendering in HTML markup.

var htmlEncoded = Server.HtmlEncode("<html>");