I'm using the latest version of razor from.
https://github.com/Antaris/RazorEngine
I want to attached it to some cshtml and debug against it.
The readme states the following
Debugging
One thing you might want to enable is the debugging feature:
config.Debug = true;
When Debug is true you can straight up debug into the generated code. RazorEngine also supports debugging directly into the
template files (normally .cshtml files). As as you might see in the
above code there is no file to debug into. To provide RazorEngine with
the necessary information you need to tell where the file can be
found:
string template = "Hello #Model.Name, welcome to RazorEngine!";
string templateFile = "C:/mytemplate.cshtml"
var result = Engine.Razor.RunCompile(new LoadedTemplateSource(template, templateFile), "templateKey", null, new {
In my code i have setup the following
var config = new TemplateServiceConfiguration();
// .. configure your instance
config.Debug = true;
var service = RazorEngineService.Create(config);
Engine.Razor = service;
//string template = "Hello #Model.Name, welcome to RazorEngine!";
string templateFile = "C:/mytemplate.cshtml";
var template = new LoadedTemplateSource("", templateFile);
var result = Engine.Razor.RunCompile(template, this.Name, null, model);
Now I have created a cshtml file at that path with the following in it.
#{
var a = 1;
a = a + a;
#a
}
<div>
hi
</div>
But I get returned an empty string :(
And when i f11 into it it just steps over :( :(.
Im not sure what im doing wrong anyone got any ideas.
Answer code
string templateFile = "C:/mytemplate.cshtml";
StringBuilder sb = new StringBuilder();
using (StreamReader sr = new StreamReader(templateFile))
{
String line;
// Read and display lines from the file until the end of
// the file is reached.
while ((line = sr.ReadLine()) != null)
{
sb.AppendLine(line);
}
}
string allines = sb.ToString();
var template = new LoadedTemplateSource(allines, templateFile);
var result = Engine.Razor.RunCompile(template, this.Name, null, model);
The LoadedTemplateSource represents the template source code, and you have given "" as the source code, therefore your template is empty.
The first parameter of LoadedTemplateSource needs to be the source code of the template and the second one is the path to the file, which is only used for debugging purposes.
If you need lazy loading or a custom loader strategy you can either implement a custom ITemplateSource or ITemplateManager, however having the source available in memory all time improves some error messages as well.
matthid, a RazorEngine Contributor
Disabling "Enable Just My Code" in Options > Debugging > General worked for me.
Related
string template = "Hello #Model.Name, welcome to RazorEngine!";
var result = Engine.Razor.RunCompile(template, "templateKey", null, new { Name = "World" });
Now i update my existing template to as below. I get my template from database.
string template = "Hello #Model.Name, welcome to My World!";
Whenever i do that i get an error The same key was already used for another template.
What is the best way to fix this issue?
The issue is that you are not using a template key that is unique to the template code you are passing in. RazorEngine caches the templates and compiles them so the next time round it's faster to run.
var helloTemplate = "Hello #Model.Name";
string result;
var model = new { Name = "World" };
//Has the template already been used? If so, Run without compilation is faster
if(Engine.Razor.IsTemplateCached("helloTemplate", null))
{
result = Engine.Razor.Run("helloTemplate", null, model);
}
else
{
result = Engine.Razor.RunCompile(helloTemplate, "helloTemplate", null, model);
}
I have a program that sends emails utilizing templates via a web service. To test the templates, I made a simple program that reads the templates, fills it up with dummy value and send it. The problem is that the templates have different 'fill in' variable names. So what I want to do is open the template, make a list of the variables and then fill them with dummy text.
Right no I have something like:
StreamReader SR = new StreamReader(myPath);
.... //Email code here
Msg.Body = SR.ReadToEnd();
SR.Close();
Msg.Body = Msg.Body.Replace(%myFillInVariable%, "Test String");
....
So I'm thinking, opening the template, search for values in between "%" and put them in an ArrayList, then do the Msg.Body = SR.ReadToEnd(); part. Loop the ArrayList and do the Replace part using the value of the Array.
What I can't find is how to read the value between the % tags. Any suggestions on what method to use will be greatly appreciated.
Thanks,
MORE DETAILS:
Sorry if I wasn't clear. I'm passing the name of the TEMPLATE to the script from a drop down. I might have a few dozen Templates and they all have different %VariableToBeReplace%. So that's is why I want to read the Template with the StreamReader, find all the %value names%, put them into an array AND THEN fill them up - which I already know how to do. It's getting the the name of what I need to replace in code which I don't know what to do.
I am not sure on your question either but here is a sample of how to do the replacement.
You can run and play with this example in LinqPad.
Copy this content into a file and change the path to what you want. Content:
Hello %FirstName% %LastName%,
We would like to welcome you and your family to our program at the low cost of %currentprice%. We are glad to offer you this %Service%
Thanks,
Some Person
Code:
var content = string.Empty;
using(var streamReader = new StreamReader(#"C:\EmailTemplate.txt"))
{
content = streamReader.ReadToEnd();
}
var matches = Regex.Matches(content, #"%(.*?)%", RegexOptions.ExplicitCapture);
var extractedReplacementVariables = new List<string>(matches.Count);
foreach(Match match in matches)
{
extractedReplacementVariables.Add(match.Value);
}
extractedReplacementVariables.Dump("Extracted KeyReplacements");
//Do your code here to populate these, this part is just to show it still works
//Modify to meet your needs
var replacementsWithValues = new Dictionary<string, string>(extractedReplacementVariables.Count);
for(var i = 0; i < extractedReplacementVariables.Count; i++)
{
replacementsWithValues.Add(extractedReplacementVariables[i], "TestValue" + i);
}
content.Dump("Template before Variable Replacement");
foreach(var key in replacementsWithValues.Keys)
{
content = content.Replace(key, replacementsWithValues[key]);
}
content.Dump("Template After Variable Replacement");
Result from LinqPad:
I am not really sure that I understood your question but, you can try to put on the first line of the template your 'fill in variable'.
Something like:
StreamReader SR = new StreamReader(myPath);
String fill_in_var=SR.ReadLine();
String line;
while((line = SR.ReadLine()) != null)
{
Msg.Body+=line;
}
SR.Close();
Msg.Body = Msg.Body.Replace(fill_in_var, "Test String");
I'm trying to use libgit2sharp to get a previous version of a file. I would prefer the working directory to remain as is, at the very least restored to previous condition.
My initial approach was to try to stash, checkout path on the file I want, save that to a string variable, then stash pop. Is there a way to stash pop? I can't find it easily. Here's the code I have so far:
using (var repo = new Repository(DirectoryPath, null))
{
var currentCommit = repo.Head.Tip.Sha;
var commit = repo.Commits.Where(c => c.Sha == commitHash).FirstOrDefault();
if (commit == null)
return null;
var sn = "Stash Name";
var now = new DateTimeOffset(DateTime.Now);
var diffCount = repo.Diff.Compare().Count();
if(diffCount > 0)
repo.Stashes.Add(new Signature(sn, "x#y.com", now), options: StashModifiers.Default);
repo.CheckoutPaths(commit.Sha, new List<string>{ path }, CheckoutModifiers.None, null, null);
var fileText = File.ReadAllText(path);
repo.CheckoutPaths(currentCommit, new List<string>{path}, CheckoutModifiers.None, null, null);
if(diffCount > 0)
; // stash Pop?
}
If there's an easier approach than using Stash, that would work great also.
Is there a way to stash pop? I can't find it easily
Unfortunately, Stash pop requires merging which isn't available yet in libgit2.
I'm trying to use libgit2sharp to get a previous version of a file. I would prefer the working directory to remain as is
You may achieve such result by opening two instances of the same repository, each of them pointing to different working directories. The Repository constructor accepts a RepositoryOptions parameter which should allow you to do just that.
The following piece of code demonstrates this feature. This creates an additional instance (otherRepo) that you can use to retrieve a different version of the file currently checked out in your main working directory.
string repoPath = "path/to/your/repo";
// Create a temp folder for a second working directory
string tempWorkDir = Path.Combine(Path.GetTempPath(), "tmp_wd");
Directory.CreateDirectory(newWorkdir);
// Also create a new index to not alter the main repository
string tempIndex = Path.Combine(Path.GetTempPath(), "tmp_idx");
var opts = new RepositoryOptions
{
WorkingDirectoryPath = tempWorkDir,
IndexPath = tempIndex
};
using (var mainRepo = new Repository(repoPath))
using (var otherRepo = new Repository(mainRepo.Info.Path, opts))
{
string path = "file.txt";
// Do your stuff with mainrepo
mainRepo.CheckoutPaths("HEAD", new[] { path });
var currentVersion = File.ReadAllText(Path.Combine(mainRepo.Info.WorkingDirectory, path));
// Use otherRepo to temporarily checkout previous versions of files
// Thank to the passed in RepositoryOptions, this checkout will not
// alter the workdir nor the index of the main repository.
otherRepo.CheckoutPaths("HEAD~2", new [] { path });
var olderVersion = File.ReadAllText(Path.Combine(otherRepo.Info.WorkingDirectory, path));
}
You can get a better grasp of this RepositoryOptions type by taking a look at the tests in RepositoryOptionFixture that exercise it.
Is there a better way to generate HTML email in C# (for sending via System.Net.Mail), than using a Stringbuilder to do the following:
string userName = "John Doe";
StringBuilder mailBody = new StringBuilder();
mailBody.AppendFormat("<h1>Heading Here</h1>");
mailBody.AppendFormat("Dear {0}," userName);
mailBody.AppendFormat("<br />");
mailBody.AppendFormat("<p>First part of the email body goes here</p>");
and so on, and so forth?
You can use the MailDefinition class.
This is how you use it:
MailDefinition md = new MailDefinition();
md.From = "test#domain.example";
md.IsBodyHtml = true;
md.Subject = "Test of MailDefinition";
ListDictionary replacements = new ListDictionary();
replacements.Add("{name}", "Martin");
replacements.Add("{country}", "Denmark");
string body = "<div>Hello {name} You're from {country}.</div>";
MailMessage msg = md.CreateMailMessage("you#anywhere.example", replacements, body, new System.Web.UI.Control());
Also, I've written a blog post on how to generate HTML e-mail body in C# using templates using the MailDefinition class.
Use the System.Web.UI.HtmlTextWriter class.
StringWriter writer = new StringWriter();
HtmlTextWriter html = new HtmlTextWriter(writer);
html.RenderBeginTag(HtmlTextWriterTag.H1);
html.WriteEncodedText("Heading Here");
html.RenderEndTag();
html.WriteEncodedText(String.Format("Dear {0}", userName));
html.WriteBreak();
html.RenderBeginTag(HtmlTextWriterTag.P);
html.WriteEncodedText("First part of the email body goes here");
html.RenderEndTag();
html.Flush();
string htmlString = writer.ToString();
For extensive HTML that includes the creation of style attributes HtmlTextWriter is probably the best way to go. However it can be a bit clunky to use and some developers like the markup itself to be easily read but perversly HtmlTextWriter's choices with regard indentation is a bit wierd.
In this example you can also use XmlTextWriter quite effectively:-
writer = new StringWriter();
XmlTextWriter xml = new XmlTextWriter(writer);
xml.Formatting = Formatting.Indented;
xml.WriteElementString("h1", "Heading Here");
xml.WriteString(String.Format("Dear {0}", userName));
xml.WriteStartElement("br");
xml.WriteEndElement();
xml.WriteElementString("p", "First part of the email body goes here");
xml.Flush();
Updated Answer:
The documentation for SmtpClient, the class used in this answer, now reads, 'Obsolete("SmtpClient and its network of types are poorly designed, we strongly recommend you use https://github.com/jstedfast/MailKit and https://github.com/jstedfast/MimeKit instead")'.
Source: https://www.infoq.com/news/2017/04/MailKit-MimeKit-Official
Original Answer:
Using the MailDefinition class is the wrong approach. Yes, it's handy, but it's also primitive and depends on web UI controls--that doesn't make sense for something that is typically a server-side task.
The approach presented below is based on MSDN documentation and Qureshi's post on CodeProject.com.
NOTE: This example extracts the HTML file, images, and attachments from embedded resources, but using other alternatives to get streams for these elements are fine, e.g. hard-coded strings, local files, and so on.
Stream htmlStream = null;
Stream imageStream = null;
Stream fileStream = null;
try
{
// Create the message.
var from = new MailAddress(FROM_EMAIL, FROM_NAME);
var to = new MailAddress(TO_EMAIL, TO_NAME);
var msg = new MailMessage(from, to);
msg.Subject = SUBJECT;
msg.SubjectEncoding = Encoding.UTF8;
// Get the HTML from an embedded resource.
var assembly = Assembly.GetExecutingAssembly();
htmlStream = assembly.GetManifestResourceStream(HTML_RESOURCE_PATH);
// Perform replacements on the HTML file (if you're using it as a template).
var reader = new StreamReader(htmlStream);
var body = reader
.ReadToEnd()
.Replace("%TEMPLATE_TOKEN1%", TOKEN1_VALUE)
.Replace("%TEMPLATE_TOKEN2%", TOKEN2_VALUE); // and so on...
// Create an alternate view and add it to the email.
var altView = AlternateView.CreateAlternateViewFromString(body, null, MediaTypeNames.Text.Html);
msg.AlternateViews.Add(altView);
// Get the image from an embedded resource. The <img> tag in the HTML is:
// <img src="pid:IMAGE.PNG">
imageStream = assembly.GetManifestResourceStream(IMAGE_RESOURCE_PATH);
var linkedImage = new LinkedResource(imageStream, "image/png");
linkedImage.ContentId = "IMAGE.PNG";
altView.LinkedResources.Add(linkedImage);
// Get the attachment from an embedded resource.
fileStream = assembly.GetManifestResourceStream(FILE_RESOURCE_PATH);
var file = new Attachment(fileStream, MediaTypeNames.Application.Pdf);
file.Name = "FILE.PDF";
msg.Attachments.Add(file);
// Send the email
var client = new SmtpClient(...);
client.Credentials = new NetworkCredential(...);
client.Send(msg);
}
finally
{
if (fileStream != null) fileStream.Dispose();
if (imageStream != null) imageStream.Dispose();
if (htmlStream != null) htmlStream.Dispose();
}
I use dotLiquid for exactly this task.
It takes a template, and fills special identifiers with the content of an anonymous object.
//define template
String templateSource = "<h1>{{Heading}}</h1>Dear {{UserName}},<br/><p>First part of the email body goes here");
Template bodyTemplate = Template.Parse(templateSource); // Parses and compiles the template source
//Create DTO for the renderer
var bodyDto = new {
Heading = "Heading Here",
UserName = userName
};
String bodyText = bodyTemplate.Render(Hash.FromAnonymousObject(bodyDto));
It also works with collections, see some online examples.
I would recomend using templates of some sort. There are various different ways to approach this but essentially hold a template of the Email some where (on disk, in a database etc) and simply insert the key data (IE: Recipients name etc) into the template.
This is far more flexible because it means you can alter the template as required without having to alter your code. In my experience your likely to get requests for changes to the templates from end users. If you want to go the whole hog you could include a template editor.
As an alternative to MailDefinition, have a look at RazorEngine https://github.com/Antaris/RazorEngine.
This looks like a better solution.
Attributted to...
how to send email wth email template c#
E.g
using RazorEngine;
using RazorEngine.Templating;
using System;
namespace RazorEngineTest
{
class Program
{
static void Main(string[] args)
{
string template =
#"<h1>Heading Here</h1>
Dear #Model.UserName,
<br />
<p>First part of the email body goes here</p>";
const string templateKey = "tpl";
// Better to compile once
Engine.Razor.AddTemplate(templateKey, template);
Engine.Razor.Compile(templateKey);
// Run is quicker than compile and run
string output = Engine.Razor.Run(
templateKey,
model: new
{
UserName = "Fred"
});
Console.WriteLine(output);
}
}
}
Which outputs...
<h1>Heading Here</h1>
Dear Fred,
<br />
<p>First part of the email body goes here</p>
Heading Here Dear Fred, First part of the email
body goes here
Emitting handbuilt html like this is probably the best way so long as the markup isn't too complicated. The stringbuilder only starts to pay you back in terms of efficiency after about three concatenations, so for really simple stuff string + string will do.
Other than that you can start to use the html controls (System.Web.UI.HtmlControls) and render them, that way you can sometimes inherit them and make your own clasess for complex conditional layout.
If you don't want a dependency on the full .NET Framework, there's also a library that makes your code look like:
string userName = "John Doe";
var mailBody = new HTML {
new H(1) {
"Heading Here"
},
new P {
string.Format("Dear {0},", userName),
new Br()
},
new P {
"First part of the email body goes here"
}
};
string htmlString = mailBody.Render();
It's open source, you can download it from http://sourceforge.net/projects/htmlplusplus/
Disclaimer: I'm the author of this library, it was written to solve the same issue exactly - send an HTML email from an application.
You might want to have a look at some of the template frameworks that are available at the moment. Some of them are spin offs as a result of MVC but that isn't required. Spark is a good one.
A commercial version which I use in production and allows for easy maintenance is LimiLabs Template Engine, been using it for 3+ years and allows me to make changes to the text template without having to update code (disclaimers, links etc..) - it could be as simple as
Contact templateData = ...;
string html = Template
.FromFile("template.txt")
.DataFrom(templateData )
.Render();
Worth taking a look at, like I did; after attempting various answers mentioned here.
Is there a better way to generate HTML email in C# (for sending via System.Net.Mail), than using a Stringbuilder to do the following:
string userName = "John Doe";
StringBuilder mailBody = new StringBuilder();
mailBody.AppendFormat("<h1>Heading Here</h1>");
mailBody.AppendFormat("Dear {0}," userName);
mailBody.AppendFormat("<br />");
mailBody.AppendFormat("<p>First part of the email body goes here</p>");
and so on, and so forth?
You can use the MailDefinition class.
This is how you use it:
MailDefinition md = new MailDefinition();
md.From = "test#domain.example";
md.IsBodyHtml = true;
md.Subject = "Test of MailDefinition";
ListDictionary replacements = new ListDictionary();
replacements.Add("{name}", "Martin");
replacements.Add("{country}", "Denmark");
string body = "<div>Hello {name} You're from {country}.</div>";
MailMessage msg = md.CreateMailMessage("you#anywhere.example", replacements, body, new System.Web.UI.Control());
Also, I've written a blog post on how to generate HTML e-mail body in C# using templates using the MailDefinition class.
Use the System.Web.UI.HtmlTextWriter class.
StringWriter writer = new StringWriter();
HtmlTextWriter html = new HtmlTextWriter(writer);
html.RenderBeginTag(HtmlTextWriterTag.H1);
html.WriteEncodedText("Heading Here");
html.RenderEndTag();
html.WriteEncodedText(String.Format("Dear {0}", userName));
html.WriteBreak();
html.RenderBeginTag(HtmlTextWriterTag.P);
html.WriteEncodedText("First part of the email body goes here");
html.RenderEndTag();
html.Flush();
string htmlString = writer.ToString();
For extensive HTML that includes the creation of style attributes HtmlTextWriter is probably the best way to go. However it can be a bit clunky to use and some developers like the markup itself to be easily read but perversly HtmlTextWriter's choices with regard indentation is a bit wierd.
In this example you can also use XmlTextWriter quite effectively:-
writer = new StringWriter();
XmlTextWriter xml = new XmlTextWriter(writer);
xml.Formatting = Formatting.Indented;
xml.WriteElementString("h1", "Heading Here");
xml.WriteString(String.Format("Dear {0}", userName));
xml.WriteStartElement("br");
xml.WriteEndElement();
xml.WriteElementString("p", "First part of the email body goes here");
xml.Flush();
Updated Answer:
The documentation for SmtpClient, the class used in this answer, now reads, 'Obsolete("SmtpClient and its network of types are poorly designed, we strongly recommend you use https://github.com/jstedfast/MailKit and https://github.com/jstedfast/MimeKit instead")'.
Source: https://www.infoq.com/news/2017/04/MailKit-MimeKit-Official
Original Answer:
Using the MailDefinition class is the wrong approach. Yes, it's handy, but it's also primitive and depends on web UI controls--that doesn't make sense for something that is typically a server-side task.
The approach presented below is based on MSDN documentation and Qureshi's post on CodeProject.com.
NOTE: This example extracts the HTML file, images, and attachments from embedded resources, but using other alternatives to get streams for these elements are fine, e.g. hard-coded strings, local files, and so on.
Stream htmlStream = null;
Stream imageStream = null;
Stream fileStream = null;
try
{
// Create the message.
var from = new MailAddress(FROM_EMAIL, FROM_NAME);
var to = new MailAddress(TO_EMAIL, TO_NAME);
var msg = new MailMessage(from, to);
msg.Subject = SUBJECT;
msg.SubjectEncoding = Encoding.UTF8;
// Get the HTML from an embedded resource.
var assembly = Assembly.GetExecutingAssembly();
htmlStream = assembly.GetManifestResourceStream(HTML_RESOURCE_PATH);
// Perform replacements on the HTML file (if you're using it as a template).
var reader = new StreamReader(htmlStream);
var body = reader
.ReadToEnd()
.Replace("%TEMPLATE_TOKEN1%", TOKEN1_VALUE)
.Replace("%TEMPLATE_TOKEN2%", TOKEN2_VALUE); // and so on...
// Create an alternate view and add it to the email.
var altView = AlternateView.CreateAlternateViewFromString(body, null, MediaTypeNames.Text.Html);
msg.AlternateViews.Add(altView);
// Get the image from an embedded resource. The <img> tag in the HTML is:
// <img src="pid:IMAGE.PNG">
imageStream = assembly.GetManifestResourceStream(IMAGE_RESOURCE_PATH);
var linkedImage = new LinkedResource(imageStream, "image/png");
linkedImage.ContentId = "IMAGE.PNG";
altView.LinkedResources.Add(linkedImage);
// Get the attachment from an embedded resource.
fileStream = assembly.GetManifestResourceStream(FILE_RESOURCE_PATH);
var file = new Attachment(fileStream, MediaTypeNames.Application.Pdf);
file.Name = "FILE.PDF";
msg.Attachments.Add(file);
// Send the email
var client = new SmtpClient(...);
client.Credentials = new NetworkCredential(...);
client.Send(msg);
}
finally
{
if (fileStream != null) fileStream.Dispose();
if (imageStream != null) imageStream.Dispose();
if (htmlStream != null) htmlStream.Dispose();
}
I use dotLiquid for exactly this task.
It takes a template, and fills special identifiers with the content of an anonymous object.
//define template
String templateSource = "<h1>{{Heading}}</h1>Dear {{UserName}},<br/><p>First part of the email body goes here");
Template bodyTemplate = Template.Parse(templateSource); // Parses and compiles the template source
//Create DTO for the renderer
var bodyDto = new {
Heading = "Heading Here",
UserName = userName
};
String bodyText = bodyTemplate.Render(Hash.FromAnonymousObject(bodyDto));
It also works with collections, see some online examples.
I would recomend using templates of some sort. There are various different ways to approach this but essentially hold a template of the Email some where (on disk, in a database etc) and simply insert the key data (IE: Recipients name etc) into the template.
This is far more flexible because it means you can alter the template as required without having to alter your code. In my experience your likely to get requests for changes to the templates from end users. If you want to go the whole hog you could include a template editor.
As an alternative to MailDefinition, have a look at RazorEngine https://github.com/Antaris/RazorEngine.
This looks like a better solution.
Attributted to...
how to send email wth email template c#
E.g
using RazorEngine;
using RazorEngine.Templating;
using System;
namespace RazorEngineTest
{
class Program
{
static void Main(string[] args)
{
string template =
#"<h1>Heading Here</h1>
Dear #Model.UserName,
<br />
<p>First part of the email body goes here</p>";
const string templateKey = "tpl";
// Better to compile once
Engine.Razor.AddTemplate(templateKey, template);
Engine.Razor.Compile(templateKey);
// Run is quicker than compile and run
string output = Engine.Razor.Run(
templateKey,
model: new
{
UserName = "Fred"
});
Console.WriteLine(output);
}
}
}
Which outputs...
<h1>Heading Here</h1>
Dear Fred,
<br />
<p>First part of the email body goes here</p>
Heading Here Dear Fred, First part of the email
body goes here
Emitting handbuilt html like this is probably the best way so long as the markup isn't too complicated. The stringbuilder only starts to pay you back in terms of efficiency after about three concatenations, so for really simple stuff string + string will do.
Other than that you can start to use the html controls (System.Web.UI.HtmlControls) and render them, that way you can sometimes inherit them and make your own clasess for complex conditional layout.
If you don't want a dependency on the full .NET Framework, there's also a library that makes your code look like:
string userName = "John Doe";
var mailBody = new HTML {
new H(1) {
"Heading Here"
},
new P {
string.Format("Dear {0},", userName),
new Br()
},
new P {
"First part of the email body goes here"
}
};
string htmlString = mailBody.Render();
It's open source, you can download it from http://sourceforge.net/projects/htmlplusplus/
Disclaimer: I'm the author of this library, it was written to solve the same issue exactly - send an HTML email from an application.
You might want to have a look at some of the template frameworks that are available at the moment. Some of them are spin offs as a result of MVC but that isn't required. Spark is a good one.
A commercial version which I use in production and allows for easy maintenance is LimiLabs Template Engine, been using it for 3+ years and allows me to make changes to the text template without having to update code (disclaimers, links etc..) - it could be as simple as
Contact templateData = ...;
string html = Template
.FromFile("template.txt")
.DataFrom(templateData )
.Render();
Worth taking a look at, like I did; after attempting various answers mentioned here.