Replace line break characters with br in ASP NET MVC Razor view

Question

I have a textarea control that accepts input  I am trying to later render that text to a view by simply using       Model CommentText   This is properly encoding any values   However  I want to replace the line break characters with  lt br   gt  and I can t find a way to make sure that the new br tags don t get encoded  I have tried using HtmlString but haven t had any luck yet

User · Answer

Try the following    MvcHtmlString Create Model CommentText Replace Environment NewLine    lt br   gt       Update   According to marcind s comment on this related question  the ASP NET MVC team is looking to implement something similar to the  lt    and  lt    for the Razor view engine   Update 2   We can turn any question about HTML encoding into a discussion on harmful user inputs  but enough of that already exists    Anyway  take care of potential harmful user input    MvcHtmlString Create Html Encode Model CommentText  Replace Environment NewLine    lt br   gt       Update 3  Asp Net MVC 3     Html Raw Html Encode Model CommentText  Replace   n     lt br   gt

User · Answer

Omar s third solution as an HTML Helper would be   public static IHtmlString FormatNewLines this HtmlHelper helper  string input        return helper Raw helper Encode input  Replace   n     lt br   gt

User · Answer

Applying the DRY principle to Omar s solution  here s an HTML Helper extension   using System Web Mvc  using System Text RegularExpressions   namespace System Web Mvc Html       public static class MyHtmlHelpers           public static MvcHtmlString EncodedReplace this HtmlHelper helper  string input  string pattern  string replacement                return new MvcHtmlString Regex Replace helper Encode input   pattern  replacement                        Usage  with improved regex     Html EncodedReplace Model CommentText     n r       lt br   gt      This also has the added benefit of putting less onus on the Razor View developer to ensure security from XSS vulnerabilities     My concern with Jacob s solution is that rendering the line breaks with CSS breaks the HTML semantics

User · Answer

Split on newlines  environment agnostic  and print regularly -- no need to worry about encoding or xss    if   string IsNullOrWhiteSpace text          var lines   text Split new       r     n     StringSplitOptions RemoveEmptyEntries       foreach  var line in lines                 lt p gt  line lt  p gt             remove empty entries is optional

User · Answer

I needed to break some text into paragraphs   p  tags   so I created a simple helper using some of the recommendations in previous answers  thank you guys    public static MvcHtmlString ToParagraphs this HtmlHelper html  string value                  value   html Encode value  Replace   r   String Empty           var arr   value Split   n   Where a   gt  a Trim      string Empty           var htmlStr     lt p gt     String Join   lt  p gt  lt p gt    arr      lt  p gt            return MvcHtmlString Create htmlStr           Usage    Html ToParagraphs Model Comments

User · Answer

Use the CSS white-space property instead of opening yourself up to XSS vulnerabilities    lt span style  white-space  pre-line  gt  Model CommentText lt  span gt

User · Answer

I prefer this method as it doesn t require manually emitting markup  I use this because I m rendering Razor Pages to strings and sending them out via email  which is an environment where the white-space styling won t always work   public static IHtmlContent RenderNewlines lt TModel gt  this IHtmlHelper lt TModel gt  html  string content        if  string IsNullOrEmpty content     html is null                return null             TagBuilder brTag   new TagBuilder  br        IHtmlContent br   brTag RenderSelfClosingTag        HtmlContentBuilder htmlContent   new HtmlContentBuilder            JAS  On the off chance a browser is using LF instead of CRLF we strip out CR before splitting on LF      string lfContent   content Replace   r   string Empty  StringComparison InvariantCulture       string   lines   lfContent Split   n   StringSplitOptions None       foreach string line in lines                    htmlContent Append line               htmlContent AppendHtml br              return htmlContent

[asp.net-mvc] Replace line break characters with <br /> in ASP.NET MVC Razor view

Update:

Update 2:

Update 3 (Asp.Net MVC 3):

Examples related to asp.net-mvc

Examples related to asp.net-mvc-3

Examples related to razor