Question

I’m trying to build a simple ‘User Template’ system so that my users can edit the layout of RSS feed items and system-generated emails without messing with view files and such. This is the function I’m using to replace the tags in a string with content:

private const string URL_TAG_REGEX = @'{{(?<TagName>\w*)}}'; private static string ReplaceTags(string content,      Dictionary<string, object> values) {         Regex r = new Regex(UT_TAG_REGEX);         foreach (string tag in values.Keys) {             content = r.Replace(content,                  m => (m.Groups['TagName'].Value == tag ?                      values[tag].ToString() : string.Empty));         }     return content; } 

My test template looks like this:

<a href='{{link}}'>{{title}}</a> - {{date}}<br /> {{description}} 

and is being rendered with this:

<%= UserTemplates.Render('overview_rss_item', new {         link = item.Link,         title = item.Title,         date = item.PublishDate,         description = item.Description     }) %> 

The Render method takes care of opening the file and converting the anonymous object to a Dictionary. It mostly works, except that only the {{link}} tag is being matched. The rest are being replaced with string.Empty.

Answer 1

Because you are replacing all the matches, and if the value doesn’t equal the tag, you’re replacing it with String.Empty. Try this:

    foreach (string tag in values.Keys) {         content = r.Replace(content,              m => (m.Groups['TagName'].Value == tag ?                  values[tag].ToString() : m.Value));     }