Is there a way to incorporate CSS directly into HTML from a local .css file when setting up a C# project? Is it possible to achieve this using PreMailer.Net?

Currently, I am working on updating a email templating system to incorporate external .css files instead of having all styles coded inline. In my ASP.NET project, it seems that the most commonly used and comprehensive inliner is PreMailer.Net. However, I am willing to explore other packages if there are better alternatives available. Here's an overview of what I am aiming to achieve:

Directory Structure

G:/templates/
  index.html
  style.css

inliner.cs

string htmlSource = File.ReadAllText("G:\\templates\\index.html");
var uri = new Uri("G:\\templates\\");
var result = PreMailer.MoveCssInline(uri, htmlSource);

index.html

<!DOCTYPE html>
<html>
    <head>
        <link rel="stylesheet" type="text/css" href='style.css'>
    </head>
    <body>
    </body>
</html>

Upon running this code snippet, I encounter the following error message:

Unable to cast object of type 'System.Net.FileWebResponse' to type 'System.Net.HttpWebResponse'.

Based on the documentation, it is unclear whether PreMailer.Net supports this specific use-case. It mentions the ability to utilize a relative URL when specifying a BaseUri parameter. The C# code that executes PreMailer.Net has access to the necessary context and can retrieve the file path, as demonstrated by successfully reading the HTML file into a string.

Answer №1

The latest version 2.1.1 of PreMailer.Net seems to have resolved the issue highlighted in this GitHub thread: link

One major improvement is the ability to fetch URIs with local filepaths like "file:///C:/website/style.css"

This feature is essential for optimizing performance by internally accessing local resources instead of making external web requests. For instance, if the CSS file is stored locally, it's more efficient to fetch it locally ("file:///C:/website/style.css") rather than externally ("https://www.example.com/style.css")

With the new update, users can initialize a PreMailer instance with BaseUri as "file:///" + new Uri(System.Web.Hosting.HostingEnvironment.MapPath("~/"), UriKind.Absolute)

This optimization technique has greatly improved the performance for my clients, and I wanted to share this code snippet here.

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

The reader is failing to retrieve database values

I am struggling with a perplexing issue that has been consuming my thoughts. The problem at hand is that the reader seems to not be picking up any information. Here's the code snippet in question: public DataEntities.Usuario GetUser(string field, st ...

Issue with checkbox click event binding in Angular 6 not functioning as expected

I am currently utilizing a reactive form to display a list of heroes to the user and would like to trigger a console log message when the user selects a hero by clicking on a checkbox. The issue I am encountering is that when I print this.form in the cons ...

challenges arise when using star icons to rate items visually, as the corresponding hidden values for backend processing are linked to radio input types

Hello, I am trying to retrieve the value of an input type radio by clicking on a star image visually. I have been successful in this, but I am having trouble resetting the star image in another row. You can view a demo of this here. I will explain what I ...

`Arc canvas countdown timer`

My countdown timer created using canvas is functioning well, but I am encountering some issues: I would like to align the circle representing seconds with the circles for minutes, hours, and days similar to this demo. Please ensure running the code snipp ...

Formatting your HTML tags in Visual Studio

For instance, I have this particular tag with concise content <div>It is brief</div> However, upon formatting, Visual Web Developer presents it as <div> It is brief</div> which is unattractive. What I desire is <div> ...

Firefox Flexbox Inline-Flex Glitch

Seeking assistance with using Flexbox to align an SVG and text within a button. The alignment works perfectly in Chrome and Safari, but Firefox is presenting some challenges. To see the issue live, check out this Codepen demonstration: Please be aware tha ...

The focus is on the last row that was selected

I've noticed that when I check and select a row in ui-grid, only the last selected row is focused with a background color. Should all rows be automatically painted by default? Thank you. ...

When the mouse hovers over DIV2, the background image of DIV1 will be replaced

I have a full-screen background div with the ID #background-change. Within that full-screen background, I have 3 Divs named .fullscreen-column-1, .fullscreen-column-2, etc. My goal is to change the background image of #background-change when the mouseove ...

Using Sass to create unique breakpoints for media queries based on the body class

I am currently in the process of creating a series of web pages that will be accessed from various websites, each with its unique content template. Even though these pages are very similar, they require different media query breakpoints based on the specif ...

Redirecting files from the file system to the emulator is not functioning properly

I am new to Phonegap and need help resolving this issue. In my application, I need to redirect to the List.html file when a button is clicked. Here is the code I have written: button1 function test() { window.location="/home/swift-03/phonegapexa ...

Find the position of an HTML5 canvas element within a webpage

I am currently facing an issue with a canvas within another canvas. <canvas id ='canvas2' height="718" width="1316"></canvas> The CSS for this canvas is as follows: #canvas2{ position:absolute; width :95%; height:90%; top:5%; lef ...

Can anyone help me with coloring Devanagiri diacritics in ReactJS?

I am currently working on a ReactJS project and I have come across an issue. I would like for the diacritic of a Devanagiri letter to be displayed in a different color than the letter it is attached to. For example: क + ी make की I was wondering ...

Issue with overflow-x in Chrome browser on mobile devices

I'm currently working on a css parallax website. Everything looks great on desktop, but when viewed on mobile devices, I encounter a horizontal scrollbar issue due to the transform3d scale (even with overflow-x:hidden applied to the parallax class). I ...

How can I transfer JSON nodes to a different object via drag-and-drop in a ListView using UWP and C#?

I'm currently developing a UWP application where I have loaded data from a JSON file and stored it. My goal is to implement drag-and-drop functionality within a listview interface to move child objects from one parent object to another. To achieve th ...

Illuminate the expanded dropdown menu in a Bootstrap 5 navbar

Bootstrap 5 navbar allows for the creation of dropdown menus. Is there a way to highlight the current menu item when a dropdown is opened, similar to how it's done in Windows desktop applications? This feature is not provided by Bootstrap 5: https:/ ...

What is the most efficient method for populating *interconnected data-dependent* <select> dropdowns in a Rails application?

When users need to choose a car from our system, they are faced with multiple dropdown menus to select the year, make, model, and submodel. The challenge lies in the fact that these options are interdependent, making it necessary to retrieve data through s ...

Error loading CSS file: 'Invalid MIME type detected, expecting text/css'

Can someone please help me figure out why none of the CSS files I linked are loading on my website? It's strange because the CSS for another page on the same site is loading without any issues. My server is built using express and I'm using ejs ...

Determining the Location of a Drag and Drop Item

I have been utilizing the code found at for implementing Drag & Drop functionality. My inquiry is: How can I retrieve the exact position (x,y) of a group once it has been dragged and dropped? ...

Establish a TTL for a collection in Azure Cosmos DB to set the expiration time as needed using C# code

I am searching for a solution to enable TTL on my Cosmos DB collection without having a default setting. My goal is to manage expiration times at the document level. If I set a default time at the collection level, it will potentially override any individ ...

Loading an assembly from stream in .NET Core: A step-by-step guide

Working with Roslyn in a .NET Core console application has been an interesting experience for me. I attempted to generate an assembly and compile it into a memory stream. However, when trying to load it, I encountered an issue where a necessary API (common ...