Question

When developing ASP.NET websites (using VB.NET web forms) – a lot of my time is spend writing CSS files and they always seem to get messy (code duplication) and very long.

All I want to achieve is to be able to manipulate the CSS using VB.NET code in the following ways:

• Use an integer variable to store my “golden” number 7 and use that for width, padding, margin etc where needed
• Use string variables to store my “golden” hex color codes e.g. “#44C5F2” and use them for color, background-color, border-color etc. where needed
• Use an integer variable to set the height of an element and have four child elements each with height: mynum / 4

I just want to use basic VB.net number and string manipulation in order to create a CSS file on the fly.

I understand that the end product – the CSS file shouldn’t change much – it should at most change on a daily basis otherwise caching couldn’t be used.

I also understand that I would lose Visual Studio CSS intellisense support but…

How do I achieve this?

Should I be using:

• Generic handlers (ASHX)
• ASP.NET Themes
• ASP.NET Skins
• Something else?

I just some pointers.

Any help is appreciated.

Thanks.

Answer 1

I decided to go with a WebHandler (ASHX file) in the end:

CssOnTheFly.ashx

<%@ WebHandler Language="C#" Class="CssOnTheFly" CodeBehind="CssOnTheFly.ashx.cs" %>

CssOnTheFly.ashx.cs

using System;
using System.Web;

public class CssOnTheFly : IHttpHandler
{

    private HttpResponse r;

    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "text/css";

        r = context.Response;

        writeCss();
    }

    public bool IsReusable
    {
        get
        {
            return false;
        }
    }

    private void writeCss()
    {
        wl("body {");
        wl("height: 100%;");
        wl("}");
    }

    private void wl(string s)
    {
        r.Write(s + Environment.NewLine);
    }
}

Because I could create bespoke classes to generate CSS on the fly – so I have more flexibility.

I think I need to use C# for this because VB.NET doesn’t really have multi-line string literals.