How to render an ASP.NET MVC view as a string?

Question

I want to output two different views (one as a string that will be sent as an email), and the other the page displayed to a user.

Is this possible in ASP.NET MVC beta?

I've tried multiple examples:

1. RenderPartial to String in ASP.NET MVC Beta

If I use this example, I receive the "Cannot redirect after HTTP headers have been sent.".

2. MVC Framework: Capturing the output of a view

If I use this, I seem to be unable to do a redirectToAction, as it tries to render a view that may not exist. If I do return the view, it is completely messed up and doesn't look right at all.

Does anyone have any ideas/solutions to these issues i have, or have any suggestions for better ones?

Many thanks!

Below is an example. What I'm trying to do is create the GetViewForEmail method:

public ActionResult OrderResult(string ref)
{
    //Get the order
    Order order = OrderService.GetOrder(ref);

    //The email helper would do the meat and veg by getting the view as a string
    //Pass the control name (OrderResultEmail) and the model (order)
    string emailView = GetViewForEmail("OrderResultEmail", order);

    //Email the order out
    EmailHelper(order, emailView);
    return View("OrderResult", order);
}

Accepted answer from Tim Scott (changed and formatted a little by me):

public virtual string RenderViewToString(
    ControllerContext controllerContext,
    string viewPath,
    string masterPath,
    ViewDataDictionary viewData,
    TempDataDictionary tempData)
{
    Stream filter = null;
    ViewPage viewPage = new ViewPage();

    //Right, create our view
    viewPage.ViewContext = new ViewContext(controllerContext, new WebFormView(viewPath, masterPath), viewData, tempData);

    //Get the response context, flush it and get the response filter.
    var response = viewPage.ViewContext.HttpContext.Response;
    response.Flush();
    var oldFilter = response.Filter;

    try
    {
        //Put a new filter into the response
        filter = new MemoryStream();
        response.Filter = filter;

        //Now render the view into the memorystream and flush the response
        viewPage.ViewContext.View.Render(viewPage.ViewContext, viewPage.ViewContext.HttpContext.Response.Output);
        response.Flush();

        //Now read the rendered view.
        filter.Position = 0;
        var reader = new StreamReader(filter, response.ContentEncoding);
        return reader.ReadToEnd();
    }
    finally
    {
        //Clean up.
        if (filter != null)
        {
            filter.Dispose();
        }

        //Now replace the response filter
        response.Filter = oldFilter;
    }
}

Example usage

Assuming a call from the controller to get the order confirmation email, passing the Site.Master location.

string myString = RenderViewToString(this.ControllerContext, "~/Views/Order/OrderResultEmail.aspx", "~/Views/Shared/Site.Master", this.ViewData, this.TempData);

Griffe

How can you use this with a view, that is strongly typed? Ie. how can I feed a model to the page? – Guarani

Can't use this and create JsonResult afterwards, because content type cannot be set after headers have been sent (because Flush sends them). – Mcarthur

Because there's no single right answer, I suppose. :) I created a question that was specific to me, but I knew that it would be a widely asked one as well. – Griffe

The suggested solution does not work in MVC 3. – Dote

@Qua: The suggested solution is over two years old. I wouldn't expect it to work for MVC 3 either! Besides, there are better ways of doing this now. – Griffe

Answer 1

Here's what I came up with, and it's working for me. I added the following method(s) to my controller base class. (You can always make these static methods somewhere else that accept a controller as a parameter I suppose)

MVC2 .ascx style

protected string RenderViewToString<T>(string viewPath, T model) {
  ViewData.Model = model;
  using (var writer = new StringWriter()) {
    var view = new WebFormView(ControllerContext, viewPath);
    var vdd = new ViewDataDictionary<T>(model);
    var viewCxt = new ViewContext(ControllerContext, view, vdd,
                                new TempDataDictionary(), writer);
    viewCxt.View.Render(viewCxt, writer);
    return writer.ToString();
  }
}

Razor .cshtml style

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();
  }
}

Edit: added Razor code.

Photoactinic

+1 I was having nested templating issues ("tempData value must not be null") with the older RenderPartialToString method. Your solution works perfectly. – Montherlant

This is not a great solution because it forces you to write code like this: RenderViewToString ("~/Views/Application/Review.ascx", model) which is inconsistent with the whole routing concept. – Mutazilite

Rendering a view to a string is always "inconsistent with the whole routing concept", as it has nothing to do with routing. I'm not sure why an answer that works got a down vote. – Photoactinic

Awesome thank you. Also seems to work with protected string RenderViewToString(string viewPath, object model) – Shapely

I had to remove the writer parameter to the ViewContext Constructer in order to get this to compile, but then i get a MissingMethodException, which i find very odd. – Drainpipe

ControllerContext is a member of the Controller if I'm not mistaken, so it shouldn't be static. – Wetterhorn

I assume this doesn't go in a controller, and that you need to pass in a controller and modify the code accordingly. But how do you do that when testing? Instantiating the controller leaves you with a bunch of nulls for the context and other stuff, so this doesn't work. – Tangerine

This is a method on my controller's base class. The environment I'm working in is not test driven, however we do run tests and this hasn't presented itself as a problem. – Photoactinic

I think you might need to remove the "static" from the Razor version's method declaration, otherwise it can't find ControllerContext et al. – Pisarik

Hahaha... good catch! You should get some sort of reward for finding that after months of other people viewing it. – Photoactinic

I'm getting a lot of the break, tab tags (\t, \n, \r, etc...), is there a way to remove these? Thanks. – Digester

@Saxman: I'm not sure what you're asking. If they're showing up like that in the IDE, it's just showing you what characters are in there, once it's written out to anything those won't appear as escaped characters, but rather as actual tabs and new lines. If you want to strip the extra whitespaces from your HTML, you're going to have to use another method, preferably something that uses XMLWriter to write it out to a string like the method outlined here. Just change the Formatting to Formatting.None. – Photoactinic

When I view the JSON object that get returned from rendering a Razor partial view to string using your method, all the tabs and spaces, line-breaks, etc... (for formatting purposes in Visual Studio) became part of the result. I wonder if these can be removed so it's cleaner and take less bandwidth. Thanks. – Digester

You'll need to implement your own method of removal for those superfluous whitespaces. The best way I can think of off the top of my head is to load the string into an XmlDocument, then write it back out to a string with an XmlWriter, as per the link I left in my last comment. I really hope that helps. – Photoactinic

Hmm how should I do this using a WebApi Controller, any suggestions would be appreciated – Sequel

This code does not return the complete html if the view contains @Html.RenderAction calls inside. I mean, if the view contains partial views to be rendered, those are not rendered. Instead of them, the resulting string contains empty spaces. Any hints on that? here's the question I just placed: #17537501 – Specs

Well, I presume you've answered this yourself since your question has been deleted. What did you come up with? I was going to suggest maybe trying Html.Action instead of Html.RenderAction – Photoactinic

Does this still work with MVC 5 or Visual Studio 2013? I'm suddenly getting very distorted HTML e.g. stuff like '<$A$><div</$A$><$B$> class="review"</$B$><$C$> id="</$C$><$D$>review</$D$>' – Unblessed

my razor: @Html.TextBoxFor(m => m.OrderedQuantity, new { data_mini = "true", name="somename", type = "number", @class = "orderedQuantity removeGroupsRequired" }) and the result: <input class="orderedQuantity removeGroupsRequired" data-mini="true" data-val="true" data-val-number="The field Quantity: must be a number." data-val-required="The Quantity: field is required." id="OrderedQuantity" name="OrderedQuantity" type="number" value="0" />...so I just lost the name, and I really need it... – Hestia

Hi everyone to use it with "Static" keyword for all controllers to make it common you have to make static class and inside it you have to put this method with "this" as parameter to "ControllerContext" . You can see here https://mcmap.net/q/73872/-how-to-render-an-asp-net-mvc-view-as-a-string it . – Orland

This code works great but I have javascript running a few calculations and displaying other jQuery rendered content. None of this gets updated when the view is rendered to a string. Even when I place my <script></script> inline and not in @section Scripts it still doesn't run the javascript code. Is this common or just me? – Caucus

@fields.cage: I'm not really sure what you're trying to do. You may want to ask a question on this site. It sounds like you're expecting the JavaScript to be processed when a view is rendered in MVC. This never happens. All JavaScript is processed at the browser. – Photoactinic

This code is tricky to test but it can be done. https://mcmap.net/q/75149/-how-do-i-mock-controller-context-in-my-unit-test-so-that-my-partial-view-to-string-function-works/354144 – Diamagnet

This seems to remove validation, is there anyway to keep validation? – Subversive

nevermind, calling $.validator.unobtrusive.parse(document); inside onSuccess seemed to work. – Subversive

how to pass an object of collection, ie ToList() or AsQueryable() object ? – Lapel

If you are having issues with HtmlHelpers in these views, try adding ViewData.ModelState.Clear(); at the start of the method. – Footle

Answer 2

This answer is not on my way . This is originally from https://mcmap.net/q/73872/-how-to-render-an-asp-net-mvc-view-as-a-string but here I have show the way to use it with "Static" Keyword to make it common for all Controllers .

For that you have to make static class in class file . (Suppose your Class File Name is Utils.cs )

This example is For Razor.

Utils.cs

public static class RazorViewToString
{
    public static string RenderRazorViewToString(this Controller controller, string viewName, object model)
    {
        controller.ViewData.Model = model;
        using (var sw = new StringWriter())
        {
            var viewResult = ViewEngines.Engines.FindPartialView(controller.ControllerContext, viewName);
            var viewContext = new ViewContext(controller.ControllerContext, viewResult.View, controller.ViewData, controller.TempData, sw);
            viewResult.View.Render(viewContext, sw);
            viewResult.ViewEngine.ReleaseView(controller.ControllerContext, viewResult.View);
            return sw.GetStringBuilder().ToString();
        }
    }
}

Now you can call this class from your controller by adding NameSpace in your Controller File as following way by passing "this" as parameter to Controller.

string result = RazorViewToString.RenderRazorViewToString(this ,"ViewName", model);

As suggestion given by @Sergey this extension method can also call from cotroller as given below

string result = this.RenderRazorViewToString("ViewName", model);

I hope this will be useful to you make code clean and neat.

Plaudit

Nice solution! One thing, RenderRazorViewToString is actually extension method (because you pass controller parameter with this keyword), so this extension method can be called this way: this.RenderRazorViewToString("ViewName", model); – Obsessive

@Obsessive Hmmm... Let me check in that way, if it is fine than I will update my answer. Anyway Thanks for your suggestion. – Orland

Dilip0165, I got an null reference error on var viewResult = ViewEngines.Engines.FindPartialView(controller.ControllerContext, viewName);. Do you have any idea? – Pyrethrin

@Pyrethrin I think it could be the issue of "viewName" which you are passing into function. You have to pass "viewName" with full path as per your folder structure. So check out this thing. – Orland

@Plaudit I have two projects (Project A and ProjectB) in the same solution. The Partial View is located in the View/Applications/_MyBody.cshtml under ProjectB and I am calling it from a class within ProjectA. I tried many differnt 'path' that i could think of but it all give me the same error. Could you recommend what a path would be in this case? – Pyrethrin

Cannot resolve symbol ViewEngines. Do you know how to resolve this error? – Nickelplate

Why jquery changes not applied to view before render? – Beth

@Obsessive Thanks for your suggestion, I have updated my answer as per your suggestion which is totally correct – Orland

It does not work in .net core 2.1, the ViewContext does not have controller parameter :/ any idea ? – Gleaning

Answer 3

This works for me:

public virtual string RenderView(ViewContext viewContext)
{
    var response = viewContext.HttpContext.Response;
    response.Flush();
    var oldFilter = response.Filter;
    Stream filter = null;
    try
    {
        filter = new MemoryStream();
        response.Filter = filter;
        viewContext.View.Render(viewContext, viewContext.HttpContext.Response.Output);
        response.Flush();
        filter.Position = 0;
        var reader = new StreamReader(filter, response.ContentEncoding);
        return reader.ReadToEnd();
    }
    finally
    {
        if (filter != null)
        {
            filter.Dispose();
        }
        response.Filter = oldFilter;
    }
}

Daemon

Thanks for your comment, but isn't that used for rendering inside a view though? How could I use it in the context I have updated the question with? – Griffe

Sorry, still thinking about Silverlight last year whose first rc was 0. :) I'm giving this a shot today. (As soon as I work out the correct format of the view path) – Stickinthemud

This still breaks redirects in RC1 – Derk

defeated: No, it doesn't. If it does, then you're doing something wrong. – Griffe

Merged this with #521363, added awareness of ViewEnginesCollection, tried to pop partialview and got this #521363. :E – Mcarthur

unfortunately this breaks with RenderPartial inside the .ascx – Enswathe

Answer 4

I found a new solution that renders a view to string without having to mess with the Response stream of the current HttpContext (which doesn't allow you to change the response's ContentType or other headers).

Basically, all you do is create a fake HttpContext for the view to render itself:

/// <summary>Renders a view to string.</summary>
public static string RenderViewToString(this Controller controller,
                                        string viewName, object viewData) {
    //Create memory writer
    var sb = new StringBuilder();
    var memWriter = new StringWriter(sb);

    //Create fake http context to render the view
    var fakeResponse = new HttpResponse(memWriter);
    var fakeContext = new HttpContext(HttpContext.Current.Request, fakeResponse);
    var fakeControllerContext = new ControllerContext(
        new HttpContextWrapper(fakeContext),
        controller.ControllerContext.RouteData,
        controller.ControllerContext.Controller);

    var oldContext = HttpContext.Current;
    HttpContext.Current = fakeContext;

    //Use HtmlHelper to render partial view to fake context
    var html = new HtmlHelper(new ViewContext(fakeControllerContext,
        new FakeView(), new ViewDataDictionary(), new TempDataDictionary()),
        new ViewPage());
    html.RenderPartial(viewName, viewData);

    //Restore context
    HttpContext.Current = oldContext;    

    //Flush memory and return output
    memWriter.Flush();
    return sb.ToString();
}

/// <summary>Fake IView implementation used to instantiate an HtmlHelper.</summary>
public class FakeView : IView {
    #region IView Members

    public void Render(ViewContext viewContext, System.IO.TextWriter writer) {
        throw new NotImplementedException();
    }

    #endregion
}

This works on ASP.NET MVC 1.0, together with ContentResult, JsonResult, etc. (changing Headers on the original HttpResponse doesn't throw the "Server cannot set content type after HTTP headers have been sent" exception).

Update: in ASP.NET MVC 2.0 RC, the code changes a bit because we have to pass in the StringWriter used to write the view into the ViewContext:

//...

//Use HtmlHelper to render partial view to fake context
var html = new HtmlHelper(
    new ViewContext(fakeControllerContext, new FakeView(),
        new ViewDataDictionary(), new TempDataDictionary(), memWriter),
    new ViewPage());
html.RenderPartial(viewName, viewData);

//...

Amputate

There is no RenderPartial method on the HtmlHelper object. This is not possible - html.RenderPartial(viewName, viewData); – Mesa

In ASP.NET MVC release 1.0 there are a couple of RenderPartial extension methods. The one I'm using in particular is System.Web.Mvc.Html.RenderPartialExtensions.RenderPartial(this HtmlHelper, string, object). I'm unaware whether the method has been added in the latest revisions of MVC and wasn't present in earlier ones. – Amputate

Thanks. Just needed to add the System.Web.Mvc.Html namespace to the using declaration (else html.RenderPartial(..) of course wont be accessible :)) – Mesa

Does anyone have this working with the RC of MVC2? They added an additional Textwriter parameter to ViewContext. I tried just adding a new StringWriter(), but it did not work. – Promptbook

@beckelmw: I updated the response. You must pass in the original StringWriter you are using to write to the StringBuilder, not a new instance or the output of the view will be lost. – Amputate

Answer 5

This article describes how to render a View to a string in different scenarios:

1. MVC Controller calling another of its own ActionMethods
2. MVC Controller calling an ActionMethod of another MVC Controller
3. WebAPI Controller calling an ActionMethod of an MVC Controller

The solution/code is provided as a class called ViewRenderer. It is part of Rick Stahl's WestwindToolkit at GitHub.

Usage (3. - WebAPI example):

string html = ViewRenderer.RenderView("~/Areas/ReportDetail/Views/ReportDetail/Index.cshtml", ReportVM.Create(id));

Carbolize

Also as NuGet package West Wind Web MVC Utilities (nuget.org/packages/Westwind.Web.Mvc). As a bonus, the view renderer can not only render partial views, but also the entire view including the Layout. Blog article with code: weblog.west-wind.com/posts/2012/May/30/… – Youmans

It would be great if this was broken into smaller packages. The Nuget package makes a bunch of changes to your web.config and adds js files to your project, which are then not cleaned up when you uninstall it :/ – Mincing

Alas all of those are for situations where there is a host... Not appropriate for something like a unit test that wants to render the view (with data from a canned model) without any IIS or other host or browswer, or other context. – Phagy

Answer 6

If you want to forgo MVC entirely, thereby avoiding all the HttpContext mess...

using RazorEngine;
using RazorEngine.Templating; // For extension methods.

string razorText = System.IO.File.ReadAllText(razorTemplateFileLocation);
string emailBody = Engine.Razor.RunCompile(razorText, "templateKey", typeof(Model), model);

This uses the awesome open source Razor Engine here: https://github.com/Antaris/RazorEngine

Mincing

Nice! Do you know if there's a similar parsing engine for WebForms syntax? I still have some old WebForms views that can't be moved to Razor quite yet. – Griffe

Hi, i had a lot of issues with the razorengine, and the error reportingis not very nice. I dont think Url helper is supported – Jacquetta

@Jacquetta Not sure if this helps, but most of the error info is in the CompilerErrors property of the exception. – Mincing

Answer 7

Additional tip for ASP NET CORE:

Interface:

public interface IViewRenderer
{
  Task<string> RenderAsync<TModel>(Controller controller, string name, TModel model);
}

Implementation:

public class ViewRenderer : IViewRenderer
{
  private readonly IRazorViewEngine viewEngine;

  public ViewRenderer(IRazorViewEngine viewEngine) => this.viewEngine = viewEngine;

  public async Task<string> RenderAsync<TModel>(Controller controller, string name, TModel model)
  {
    ViewEngineResult viewEngineResult = this.viewEngine.FindView(controller.ControllerContext, name, false);

    if (!viewEngineResult.Success)
    {
      throw new InvalidOperationException(string.Format("Could not find view: {0}", name));
    }

    IView view = viewEngineResult.View;
    controller.ViewData.Model = model;

    await using var writer = new StringWriter();
    var viewContext = new ViewContext(
       controller.ControllerContext,
       view,
       controller.ViewData,
       controller.TempData,
       writer,
       new HtmlHelperOptions());

       await view.RenderAsync(viewContext);

       return writer.ToString();
  }
}

Registration in Startup.cs

...
 services.AddSingleton<IViewRenderer, ViewRenderer>();
...

And usage in controller:

public MyController: Controller
{
  private readonly IViewRenderer renderer;
  public MyController(IViewRendere renderer) => this.renderer = renderer;
  public async Task<IActionResult> MyViewTest
  {
    var view = await this.renderer.RenderAsync(this, "MyView", model);
    return new OkObjectResult(view);
  }
}

Erminois

Witchcraft! I may make another question specifically about asp.net core so this can be the answer for the future (at least until .NET 12). Works perfectly in .NET 6 Core MVC. – Etherize

Great! I had just to change isMainPage to true otherwise the _ViewStart.cshtml don't get executed, here: ViewEngineResult viewEngineResult = this.viewEngine.FindView(controller.ControllerContext, name, true); – Greig

Answer 8

To render a view to a string in the Service Layer without having to pass ControllerContext around, there is a good Rick Strahl article here http://www.codemag.com/Article/1312081 that creates a generic controller. Code summary below:

// Some Static Class
public static string RenderViewToString(ControllerContext context, string viewPath, object model = null, bool partial = false)
{
    // first find the ViewEngine for this view
    ViewEngineResult viewEngineResult = null;
    if (partial)
        viewEngineResult = ViewEngines.Engines.FindPartialView(context, viewPath);
    else
        viewEngineResult = ViewEngines.Engines.FindView(context, viewPath, null);

    if (viewEngineResult == null)
        throw new FileNotFoundException("View cannot be found.");

    // get the view and attach the model to view data
    var view = viewEngineResult.View;
    context.Controller.ViewData.Model = model;

    string result = null;

    using (var sw = new StringWriter())
    {
        var ctx = new ViewContext(context, view, context.Controller.ViewData, context.Controller.TempData, sw);
        view.Render(ctx, sw);
        result = sw.ToString();
    }

    return result;
}

// In the Service Class
public class GenericController : Controller
{ }

public static T CreateController<T>(RouteData routeData = null) where T : Controller, new()
{
    // create a disconnected controller instance
    T controller = new T();

    // get context wrapper from HttpContext if available
    HttpContextBase wrapper;
    if (System.Web.HttpContext.Current != null)
        wrapper = new HttpContextWrapper(System.Web.HttpContext.Current);
    else
        throw new InvalidOperationException("Cannot create Controller Context if no active HttpContext instance is available.");

    if (routeData == null)
        routeData = new RouteData();

    // add the controller routing if not existing
    if (!routeData.Values.ContainsKey("controller") &&
        !routeData.Values.ContainsKey("Controller"))
        routeData.Values.Add("controller", controller.GetType().Name.ToLower().Replace("controller", ""));

    controller.ControllerContext = new ControllerContext(wrapper, routeData, controller);
    return controller;
}

Then to render the View in the Service class:

var stringView = RenderViewToString(CreateController<GenericController>().ControllerContext, "~/Path/To/View/Location/_viewName.cshtml", theViewModel, true);

Petronia

ViewEngines no longer seems correct [.NET 5.0] – Phagy

This code is targeted at .NET Framework, not Core. – Sheepdip

Answer 9

you can get the view in string using this way

protected string RenderPartialViewToString(string viewName, object model)
{
    if (string.IsNullOrEmpty(viewName))
        viewName = ControllerContext.RouteData.GetRequiredString("action");

    if (model != null)
        ViewData.Model = model;

    using (StringWriter sw = new StringWriter())
    {
        ViewEngineResult viewResult = ViewEngines.Engines.FindPartialView(ControllerContext, viewName);
        ViewContext viewContext = new ViewContext(ControllerContext, viewResult.View, ViewData, TempData, sw);
        viewResult.View.Render(viewContext, sw);

        return sw.GetStringBuilder().ToString();
    }
}

We can call this method in two way

string strView = RenderPartialViewToString("~/Views/Shared/_Header.cshtml", null)

OR

var model = new Person()
string strView = RenderPartialViewToString("~/Views/Shared/_Header.cshtml", model)

Than

Answer 10

I am using MVC 1.0 RTM and none of the above solutions worked for me. But this one did:

Public Function RenderView(ByVal viewContext As ViewContext) As String

    Dim html As String = ""

    Dim response As HttpResponse = HttpContext.Current.Response

    Using tempWriter As New System.IO.StringWriter()

        Dim privateMethod As MethodInfo = response.GetType().GetMethod("SwitchWriter", BindingFlags.NonPublic Or BindingFlags.Instance)

        Dim currentWriter As Object = privateMethod.Invoke(response, BindingFlags.NonPublic Or BindingFlags.Instance Or BindingFlags.InvokeMethod, Nothing, New Object() {tempWriter}, Nothing)

        Try
            viewContext.View.Render(viewContext, Nothing)
            html = tempWriter.ToString()
        Finally
            privateMethod.Invoke(response, BindingFlags.NonPublic Or BindingFlags.Instance Or BindingFlags.InvokeMethod, Nothing, New Object() {currentWriter}, Nothing)
        End Try

    End Using

    Return html

End Function

Complicated

Answer 11

I saw an implementation for MVC 3 and Razor from another website, it worked for me:

    public static string RazorRender(Controller context, string DefaultAction)
    {
        string Cache = string.Empty;
        System.Text.StringBuilder sb = new System.Text.StringBuilder();
        System.IO.TextWriter tw = new System.IO.StringWriter(sb); 

        RazorView view_ = new RazorView(context.ControllerContext, DefaultAction, null, false, null);
        view_.Render(new ViewContext(context.ControllerContext, view_, new ViewDataDictionary(), new TempDataDictionary(), tw), tw);

        Cache = sb.ToString(); 

        return Cache;

    } 

    public static 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);
            return sw.GetStringBuilder().ToString();
        }
    } 

    public static class HtmlHelperExtensions
    {
        public static string RenderPartialToString(ControllerContext context, string partialViewName, ViewDataDictionary viewData, TempDataDictionary tempData)
        {
            ViewEngineResult result = ViewEngines.Engines.FindPartialView(context, partialViewName);

            if (result.View != null)
            {
                StringBuilder sb = new StringBuilder();
                using (StringWriter sw = new StringWriter(sb))
                {
                    using (HtmlTextWriter output = new HtmlTextWriter(sw))
                    {
                        ViewContext viewContext = new ViewContext(context, result.View, viewData, tempData, output);
                        result.View.Render(viewContext, output);
                    }
                }
                return sb.ToString();
            } 

            return String.Empty;

        }

    }

More on Razor render- MVC3 View Render to String

Haematic

Yes, this is actually more or less a copy of the accepted answer. :) – Griffe

Answer 12

Quick tip

For a strongly typed Model just add it to the ViewData.Model property before passing to RenderViewToString. e.g

this.ViewData.Model = new OrderResultEmailViewModel(order);
string myString = RenderViewToString(this.ControllerContext, "~/Views/Order/OrderResultEmail.aspx", "~/Views/Shared/Site.Master", this.ViewData, this.TempData);

Mceachern

Answer 13

The easiest way for me was:

  public string GetFileAsString(string path)
  {
        var html = "";                        

        FileStream fileStream = new FileStream(path, FileMode.Open);

        using (StreamReader reader = new StreamReader(fileStream))
        {
            html += reader.ReadLine();
        }

        return html;
   }

I use this for emails and make sure that the file only contains CSS and HTML

Madness

Nice solution, but it's agnostic of MVC and actually doesn't use any of it. So this will not be a suitable answer for anybody wanting to render a "real" View. – Sheepdip

Thank you for your feedback, I understand that its not related to this specific question but I just replied here with a more generic approach for anyone looking for ways to transform any file into a string without the costs of render. – Madness

Answer 14

I found a better way to render razor view page when I got error with the methods above, this solution for both web form environment and mvc environment. No controller is needed.

Here is the code example, in this example I simulated a mvc action with an async http handler:

    /// <summary>
    /// Enables processing of HTTP Web requests asynchronously by a custom HttpHandler that implements the IHttpHandler interface.
    /// </summary>
    /// <param name="context">An HttpContext object that provides references to the intrinsic server objects.</param>
    /// <returns>The task to complete the http request.</returns>
    protected override async Task ProcessRequestAsync(HttpContext context)
    {
        if (this._view == null)
        {
            this.OnError(context, new FileNotFoundException("Can not find the mvc view file.".Localize()));
            return;
        }
        object model = await this.LoadModelAsync(context);
        WebPageBase page = WebPageBase.CreateInstanceFromVirtualPath(this._view.VirtualPath);
        using (StringWriter sw = new StringWriter())
        {
            page.ExecutePageHierarchy(new WebPageContext(new HttpContextWrapper(context), page, model), sw);
            await context.Response.Output.WriteAsync(sw.GetStringBuilder().ToString());
        }
    }

Janise

Answer 15

Here is a class I wrote to do this for ASP.NETCore RC2. I use it so I can generate html email using Razor.

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Abstractions;
using Microsoft.AspNetCore.Mvc.ModelBinding;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.AspNetCore.Mvc.ViewEngines;
using Microsoft.AspNetCore.Mvc.ViewFeatures;
using Microsoft.AspNetCore.Routing;
using System.IO;
using System.Threading.Tasks;

namespace cloudscribe.Web.Common.Razor
{
    /// <summary>
    /// the goal of this class is to provide an easy way to produce an html string using 
    /// Razor templates and models, for use in generating html email.
    /// </summary>
    public class ViewRenderer
    {
        public ViewRenderer(
            ICompositeViewEngine viewEngine,
            ITempDataProvider tempDataProvider,
            IHttpContextAccessor contextAccesor)
        {
            this.viewEngine = viewEngine;
            this.tempDataProvider = tempDataProvider;
            this.contextAccesor = contextAccesor;
        }

        private ICompositeViewEngine viewEngine;
        private ITempDataProvider tempDataProvider;
        private IHttpContextAccessor contextAccesor;

        public async Task<string> RenderViewAsString<TModel>(string viewName, TModel model)
        {

            var viewData = new ViewDataDictionary<TModel>(
                        metadataProvider: new EmptyModelMetadataProvider(),
                        modelState: new ModelStateDictionary())
            {
                Model = model
            };

            var actionContext = new ActionContext(contextAccesor.HttpContext, new RouteData(), new ActionDescriptor());
            var tempData = new TempDataDictionary(contextAccesor.HttpContext, tempDataProvider);

            using (StringWriter output = new StringWriter())
            {

                ViewEngineResult viewResult = viewEngine.FindView(actionContext, viewName, true);

                ViewContext viewContext = new ViewContext(
                    actionContext,
                    viewResult.View,
                    viewData,
                    tempData,
                    output,
                    new HtmlHelperOptions()
                );

                await viewResult.View.RenderAsync(viewContext);

                return output.GetStringBuilder().ToString();
            }
        }
    }
}

Physiography

Answer 16

To repeat from a more unknown question, take a look at MvcIntegrationTestFramework.

It makes saves you writing your own helpers to stream result and is proven to work well enough. I'd assume this would be in a test project and as a bonus you would have the other testing capabilities once you've got this setup. Main bother would probably be sorting out the dependency chain.

 private static readonly string mvcAppPath = 
     Path.GetFullPath(AppDomain.CurrentDomain.BaseDirectory 
     + "\\..\\..\\..\\MyMvcApplication");
 private readonly AppHost appHost = new AppHost(mvcAppPath);

    [Test]
    public void Root_Url_Renders_Index_View()
    {
        appHost.SimulateBrowsingSession(browsingSession => {
            RequestResult result = browsingSession.ProcessRequest("");
            Assert.IsTrue(result.ResponseText.Contains("<!DOCTYPE html"));
        });
}

Varioloid