Rendering #Html.Action("actionName","controllerName") at runtime , fetching from database in MVC4 - asp.net-mvc-4

Question

My requirement is to fetch html data from database and render it on view. But if that string contains #Html.Action("actionName","controllerName"), i need to call perticular controller action method also.
I am rendering my html on view using #Html.Raw().
Eg: Below is the html string stored in my database
'<h2> Welcome To Page </h2> <br/> #Html.Action("actionName", "controllerName")'
So when it render the string, it execute mentioned controller and action too.
Any help will be appreciated.

Answer 1

You can try RazorEngine to allow string template in razor executed.
For example, sample code from the project site http://antaris.github.io/RazorEngine/:
using RazorEngine;
using RazorEngine.Templating; // For extension methods.
string template = "Hello #Model.Name, welcome to RazorEngine!";
var result =
Engine.Razor.RunCompile(template, "templateKey", null, new { Name = "World" });
But there is one catch, Html and Url helpers are defined in the Mvc framework, hence it is not supported by default.
I will suggest you try to create your template by passing model so that you don't have to use #Html.Action.
If you can not avoid it, then there is possible a solution suggested by another so answer https://stackoverflow.com/a/19434112/2564920:
[RequireNamespaces("System.Web.Mvc.Html")]
public class HtmlTemplateBase<T>:TemplateBase<T>, IViewDataContainer
{
private HtmlHelper<T> helper = null;
private ViewDataDictionary viewdata = null;
public HtmlHelper<T> Html
{
get
{
if (helper == null)
{
var writer = this.CurrentWriter; //TemplateBase.CurrentWriter
var context = new ViewContext() { RequestContext = HttpContext.Current.Request.RequestContext, Writer = writer, ViewData = this.ViewData };
helper = new HtmlHelper<T>(vcontext, this);
}
return helper;
}
}
public ViewDataDictionary ViewData
{
get
{
if (viewdata == null)
{
viewdata = new ViewDataDictionary();
viewdata.TemplateInfo = new TemplateInfo() { HtmlFieldPrefix = string.Empty };
if (this.Model != null)
{
viewdata.Model = Model;
}
}
return viewdata;
}
set
{
viewdata = value;
}
}
public override void WriteTo(TextWriter writer, object value)
{
if (writer == null)
throw new ArgumentNullException("writer");
if (value == null) return;
//try to cast to RazorEngine IEncodedString
var encodedString = value as IEncodedString;
if (encodedString != null)
{
writer.Write(encodedString);
}
else
{
//try to cast to IHtmlString (Could be returned by Mvc Html helper methods)
var htmlString = value as IHtmlString;
if (htmlString != null) writer.Write(htmlString.ToHtmlString());
else
{
//default implementation is to convert to RazorEngine encoded string
encodedString = TemplateService.EncodedStringFactory.CreateEncodedString(value);
writer.Write(encodedString);
}
}
}
}
Then you have to use HtmlTemplateBase (modified base on https://antaris.github.io/RazorEngine/TemplateBasics.html#Extending-the-template-Syntax):
var config = new TemplateServiceConfiguration();
// You can use the #inherits directive instead (this is the fallback if no #inherits is found).
config.BaseTemplateType = typeof(HtmlTemplateBase<>);
using (var service = RazorEngineService.Create(config))
{
string template = "<h2> Welcome To Page </h2> <br/> #Html.Action(\"actionName\", \"controllerName\")";
string result = service.RunCompile(template, "htmlRawTemplate", null, null);
}
in essence, it is telling the RazorEngine to use a base template where mvc is involved, so that Html and Url helper can be used.