Generating HTML using a template from a .NET application

c# .net html template-engine

29,336

Solution 1

As Matt mentioned, spark is nice but it could be overkill for some simple templates and gets complicated if you are not using it in MVC.

I have personally had a lot of success with NVelocity and I also publish a simple example/wrapper on using it: http://simpable.com/code/simpletemplate/

In addition, GraffitiCMS's entire theming system run on NVelocity (although I would have used spark if it were available for this task).

-Scott

Solution 2

One way you could do this is create a XSL file as the template, serialise your customDataObject as XML then perform a transform to generate the required HTML.

Update: Whilst I like (and do use) the string replacement method advocated by other folks here, there is a certain flexibility to using XML/XSL. Say your object has a property that is a list, for example an order object with a list of line item objects, you pretty much have to burn into your code the logic that has to render the line items.

With XSL all you do is pass the serialised order object XML to the XSL and let the XSL handle whatever HTML it needs to generate. This means you can often edit the XSL in place or have variants (order summary, detailed order etc) without adding extra code to your app with all the extra hassle of rebuild/deploy.

But then it all depends on the complexity of what you need to render, for some jobs string replacement is more obvious, for others XSL is the way. As I said, we use both.

Solution 3

Here's some code that illustrates a fairly simple way to accomplish what you're trying to do:

using System;
using System.IO;

public class HtmlTemplate
{
    private string _html;

    public HtmlTemplate(string templatePath)
    {
        using (var reader = new StreamReader(templatePath))
            _html = reader.ReadToEnd();
    }

    public string Render(object values)
    {
        string output = _html;
        foreach (var p in values.GetType().GetProperties())
            output = output.Replace("[" + p.Name + "]", (p.GetValue(values, null) as string) ?? string.Empty);
        return output;
    }
}

public class Program
{
    void Main()
    {
        var template = new HtmlTemplate(@"C:\MyTemplate.txt");
        var output = template.Render(new {
            TITLE = "My Web Page",
            METAKEYWORDS = "Keyword1, Keyword2, Keyword3",
            BODY = "Body content goes here",
            ETC = "etc"
        });
        Console.WriteLine(output);
    }
}

Using this, all you have to do is create some HTML templates and fill them with replaceable tokens such as [TITLE], [METAKEYWORDS], etc. Then pass in anonymous objects that contain the values to replace the tokens with. You could also replace the value object with a dictionary or something similar.

Solution 4

Check out docu. It uses the Spark view engine to render templated HTML from a console app. Pretty straightforward.

Solution 5

Another option instead of using XSLT as Kev suggests is to use named string formatting. Using code like this example by Phil Haack.

Here you can have your template as a string (read from a file maybe) and format it using the given object.

Now you could do something like this:

var person = new { FirstName = "rune", LastName = "grimstad" };
string template = "<html><body><h1>Hello {FirstName} {LastName}</h1></body></html>";
string html = NamedFormat(template, person);

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Author by

Mark Heath

I'm the creator of NAudio, an open source audio library for .NET. I'm interested in any ways to improve the quality of my code, and teaching others the things I learn along the way. I'm also the author of several Pluralsight courses.

Updated on July 21, 2022

Comments

Mark Heath almost 2 years
I have a .NET console application that needs to generate some HTML files. I could just construct the HTML in a StringBuilder and write the contents out to a file, but I was thinking it would be nicer to use some kind of template file with placeholders for where the data goes and then process my data through it at runtime.

I'm guessing there are ways to use aspx, or T4, or some of the alternative view engines that you can use with ASP.NET MVC, but I don't know what would be easiest to integrate into a console application (or how I would go about integrating them).

I want to end up able to call something of the form:
```
 GenerateHtml(htmlPath, template, customDataObject);
```
Mark Heath almost 15 years

this is nice, although it is lacking the ability to loop around a collection which I would need as my HTML page needs to construct a list of formatted items.
Mark Heath almost 15 years

yes I have been looking at NVelocity. it looks like the most promising solution for my problem. I am at a loss to work out where to download the "new" version that the castle project have made though.
Mark Heath almost 15 years

eventually I got it working after downloading the entire castle project source and building my own NVelocity.dll. It also took a while to work out how to load my template correctly, but once I did it meets my needs perfectly. thanks
samy about 8 years

Hey Scott, it would have been nice to have at least some pointers on this page. Apparently the website is down
Geovani Martinez almost 6 years

@samy here you go markheath.net/post/creating-html-using-nvelocity
Stephen Hosking over 2 years

I spent hours looking for an off-the-shelf solution, then just coded this in minutes and it worked perfectly. I'm interoperating with F#, which doesn't have such a clean constructor for an anonymous object, whereas it does for a dictionary, so the Dictionary worked better. The signature is public string Render(IDictionary dictionary).
Stephen Hosking over 2 years

HOWEVER! Each output = output.Replace(..) is copying the whole string, and doing one replacement, which could be expensive with a large file and many substutions. I recommend using a StringBuilder instead, so StringBuilder sb= StringBuilder(_html); ...; sb.Replace(....); return sb.ToString()
Mindaugas Bernatavičius over 2 years

Here is a template for the code given in the answer, so that people can try it out: pastebin.com/raw/mPHDE7tQ