在Controller ASP.NET MVC 4中调用RenderAction用于仪表板（多）视图

Question

I have a template HTML string, which at various unknown points has {{Url}} placeholders in it, which relate to certain controller/actions in my application. What I need to do is render the html into these placeholders, before rendering the final html in a view.

In a view I can simply call Html.RenderAction("Action","Controller") which returns the string I need. However , I need to call this method in the controller code , for example (This is simplified):

In "Dashboard" Controller:

var templateHtml = GetTemplateHtml();

//The following line doesn't compile
var html = Html.RenderAction("Index","PowerAnalysisDashpart");

ViewBag.Html = templateHtml.Replace("{{PowerAnalysisDashpart}}",html)

Then in the "Dashboard View":

<div id="content">
    @Html.Raw(ViewBag.Html)
</div>

How do I call "RenderAction" to get the Rendered HTML string in the controller?

EDIT: There seems to be confusion over what I am trying to achieve. Basically, we need administrators to be able to create an HTML template, which will effectively have frames for various different pages of our application. Iframes would work, but we'd much prefer to have all the HTML built on the server.

Answer 1

I think you want HtmlHelper.Action rather than RenderAction . RenderAction writes the content to the response stream. Action returns it as a string.

http://msdn.microsoft.com/en-us/library/ee721266(v=vs.108).aspx

Action is defined in the ChildActionExtensions class which lives in the System.Web.Mvc.Html namespace so your controller code would need to be using that namespace.

Action returns Html as a string whereas RenderAction returns void because RenderAction writes its Html output directly to the current response stream inline with the parent document. This is why it works from a view but not a controller.

To create an HtmlHelper instance in MVC 4 you can use this:

HtmlHelper helper = new HtmlHelper(new ViewContext(ControllerContext, new WebFormView(ControllerContext, "Index"), new ViewDataDictionary(), new TempDataDictionary(), new StringWriter()), new ViewPage());

As other commentors have said on related SO questions, this is not really as intended (which is obvious by the hacky way you have to instaniate the HtmlHelper). I'm not sure it's much better than your alternative solution. Better to refactor to be more MVC like if you can, although I realise sometimes that is not an option.

Answer 2

So, found a solution, but it is very hacky and there simply must be a cleaner way!

I have a shared partial view "_view", which only has this in it:

@{ Html.RenderAction("Index",(string)ViewBag.Controller); }

I have used the code from this blog: http://approache.com/blog/render-any-aspnet-mvc-actionresult-to/ to write an extension method for the ActionResult class.

Then in my controller I do this:

var templateHtml = GetTemplateHtml();
ViewBag.Controller = "PowerAnalysis";
var html = View("_view").Capture(ControllerContext);
ViewBag.Html = htmlTemplate.Replace("{{PowerAnalysis}}", html);

//Repeat for other pages

return View();

Below the code for the extension method I used from the blog:

public class ResponseCapture : IDisposable {
        private readonly HttpResponseBase response;
        private readonly TextWriter originalWriter;
        private StringWriter localWriter;
        public ResponseCapture(HttpResponseBase response) {
            this.response = response;
            originalWriter = response.Output;
            localWriter = new StringWriter();
            response.Output = localWriter;
        }
        public override string ToString() {
            localWriter.Flush();
            return localWriter.ToString();
        }
        public void Dispose() {
            if (localWriter != null) {
                localWriter.Dispose();
                localWriter = null;
                response.Output = originalWriter;
            }
        }
    }


    public static class ActionResultExtensions {
        public static string Capture(this ActionResult result, ControllerContext controllerContext) {
            using (var it = new ResponseCapture(controllerContext.RequestContext.HttpContext.Response)) {
                result.ExecuteResult(controllerContext);
                return it.ToString();
            }
        }
    }

Answer 3

I think you need partial views you can render partial view in your main view

 @Html.Partial("myPartailView")

for detail check link

http://www.codeproject.com/Tips/617361/Partial-View-in-ASP-NET-MVC-4

Answer 4

To Render view as string you can follow following approach:

var html = RenderRazorViewToString("viewName",model); //pass model if you are binding model in view


// It will return your view as string
[NonAction]
public string RenderRazorViewToString(string viewName, object model)
{
    ViewData.Model = model;
    using (var sw = new StringWriter())
    {
        var viewResult = ViewEngines.Engines.FindPartialView(ControllerContext, viewName);
        var viewContext = new ViewContext(ControllerContext, viewResult.View, ViewData, TempData, sw);
        viewResult.View.Render(viewContext, sw);
        viewResult.ViewEngine.ReleaseView(ControllerContext, viewResult.View);
        return sw.GetStringBuilder().ToString();
    }
}