Get HTML string from asp.net MVC ActionResult in controller [duplicate] - asp.net-mvc

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);

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.

This answer is not on my way . This is originally from https://stackoverflow.com/a/2759898/2318354 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.

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;
}
}

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);
//...

This article describes how to render a View to a string in different scenarios:
MVC Controller calling another of its own ActionMethods
MVC Controller calling an ActionMethod of another MVC Controller
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));

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

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);
}
}

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);

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)

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

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

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);

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"));
});
}

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();
}
}
}
}

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());
}
}

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

Related

Get link to PartialView in Orchard CMS

I want to render a RazorView to string but in Orchard CMS, but I don't know how to get link to a partial view to get string.
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();
}
}
If in another MVC Project - not Orchard - it worked OK with the code:
string result = RenderRazorViewToString("~/Views/Home/PartialViewEmail.cshtml", null);
But in Orchard CMS, it doesn't know where to get that partialview.
What should I do ?
Thanks so much !
The better solution however is to adopt the Orchard way of doing things, using shapes. If you do:
#Display.ViewEmail(SomeParameter: 42, SomeOtherParameter: "foo")
And then create a file in your theme under /Views named ViewEmail.cshtml, you can reference the parameters passed in as properties of Model if you need them. The call to Display will cause the rendering of the ViewEmail shape.
I've solve that problem. It's very simple like below
PartialViewResult path = PartialView("PartialViewEmail");
string tmp = path.ViewName;
string result = RenderRazorViewToString(tmp, null);
I've opted for an extension method like the following:
public static class ViewExtensions
{
public static string RenderToString(this PartialViewResult partialView)
{
var httpContext = HttpContext.Current;
if (httpContext == null)
{
throw new NotSupportedException("An HTTP context is required to render the partial view to a string");
}
var controllerName = httpContext.Request.RequestContext.RouteData.Values["controller"].ToString();
var controller = (ControllerBase)ControllerBuilder.Current.GetControllerFactory().CreateController(httpContext.Request.RequestContext, controllerName);
var controllerContext = new ControllerContext(httpContext.Request.RequestContext, controller);
var view = ViewEngines.Engines.FindPartialView(controllerContext, partialView.ViewName).View;
var sb = new StringBuilder();
using (var sw = new StringWriter(sb))
{
using (var tw = new HtmlTextWriter(sw))
{
view.Render(new ViewContext(controllerContext, view, partialView.ViewData, partialView.TempData, tw), tw);
}
}
return sb.ToString();
}
}
It allows me to do the following:
var html = PartialView("SomeView").RenderToString();
If I still wanted to get the full path of the view for some reason I could do the following:
var path = ((BuildManagerCompiledView)view).ViewPath; // Will be something like "~/Views/Shared/SomeView.cshtml"

Is there a way to get a PartialView HTML content in the controller?

I have a partial view with a controller with outputCache on as I need to cache this element.
Then I need to render this PartialView in every page, but first I need to do some string replacement.
So my question is, howdo I get a Partial View in a controller so I can manipulate the content and do some string replacement before returning it to the View?
Thanks
I use these methods on my custom Controller base.
public string RenderPartialToString(string partialViewName, object model)
{
InvalidateControllerContext();
IView view = ViewEngines.Engines.FindPartialView(ControllerContext, partialViewName).View;
string result = RenderViewToString(view, model);
return result;
}
public string RenderViewToString(string viewName, object model)
{
InvalidateControllerContext();
IView view = ViewEngines.Engines.FindView(ControllerContext, viewName, null).View;
string result = RenderViewToString(view, model);
return result;
}
public string RenderViewToString(IView view, object model)
{
InvalidateControllerContext();
string result = null;
if (view != null)
{
StringBuilder sb = new StringBuilder();
using (StringWriter writer = new StringWriter(sb))
{
ViewContext viewContext = new ViewContext(ControllerContext, view, new ViewDataDictionary(model), new TempDataDictionary(), writer);
view.Render(viewContext, writer);
writer.Flush();
}
result = sb.ToString();
}
return result;
}
private void InvalidateControllerContext()
{
if (ControllerContext == null)
{
ControllerContext context = new ControllerContext(System.Web.HttpContext.Current.Request.RequestContext, this);
ControllerContext = context;
}
}
The InvalidateControllerContext method is meant for the scenario where you need to instance Controllers manually in order to render partials or views outside of the context of a controller.
No, don't do this. Your controller should not render your View, that's the job of the templating engine.
Pass the "replacement" values as a model to your PartialView.
public ActionResult SomeAction()
{
SomeModelmodel = new SomeModel(); // your model
return PartialView(model); // partial view with your model
}
And the Partial View:
#model SomeModel
<div>Replace your values with #Model.Value instead of String.Replace().</div>
Just wanted to share a modification to #Nico's solution, if you want to use ViewBag data from your controller action then change RenderViewToString as follows, I use controller.TempData instead of new TempDataDictionary().
public string RenderViewToString( IView view, object model)
{
InvalidateControllerContext();
string result = null;
if (view != null)
{
StringBuilder sb = new StringBuilder();
using (StringWriter writer = new StringWriter(sb))
{
// use TempData from controller
ViewContext viewContext = new ViewContext(ControllerContext, view,
new ViewDataDictionary(model), this.TempData, writer);
view.Render(viewContext, writer);
writer.Flush();
}
result = sb.ToString();
}
return result;
}

In ASP.NET MVC controller, can I get the view result by calling an action on a different controller

I tried to simply new up a different controller and then calling the action method. The return value is of type ViewResult and the model was created, but the View is null. I guess the context in which the runtime tries to find the correct view is wrong.
How can I achieve this?
Background
Trying to see if a template controller can use a view to both render HTML e-mail to the browser as well as render to a string to be appended to the body of an MailMessage object. The second scenario will happen in a different controller, hence the problem that calling the template controller's action does not resolve the view.
This may be similar to a unit test environment where you want to check if the view result contains the content you expected.
Thanks!
michielvoo - as mentioned in the comment on OT, a few methods that may be useful if you also need to output your views or partialviews as strings (this is from my BaseController):
public static class ExtensionMethods
{
// usage
/*
var model = _repository.Find(x => x.PropertyID > 3).FirstOrDefault();
var test = this.RenderViewToString("DataModel", model);
return Content(test);
*/
public static string RenderViewToString<T>(this ControllerBase controller, string viewName, T model)
{
using (var writer = new StringWriter())
{
ViewEngineResult result = ViewEngines
.Engines
.FindView(controller.ControllerContext, viewName, null);
var viewPath = ((WebFormView)result.View).ViewPath;
var view = new WebFormView(viewPath);
var vdd = new ViewDataDictionary<T>(model);
var viewCxt = new ViewContext(controller.ControllerContext, view, vdd, new TempDataDictionary(), writer);
viewCxt.View.Render(viewCxt, writer);
return writer.ToString();
}
}
public static string RenderPartialToString<T>(this ControllerBase controller, string partialName, T model)
{
var vd = new ViewDataDictionary(controller.ViewData);
var vp = new ViewPage
{
ViewData = vd,
ViewContext = new ViewContext(),
Url = new UrlHelper(controller.ControllerContext.RequestContext)
};
ViewEngineResult result = ViewEngines
.Engines
.FindPartialView(controller.ControllerContext, partialName);
if (result.View == null)
{
throw new InvalidOperationException(
string.Format("The partial view '{0}' could not be found", partialName));
}
var partialPath = ((WebFormView)result.View).ViewPath;
vp.ViewData.Model = model;
Control control = vp.LoadControl(partialPath);
vp.Controls.Add(control);
var sb = new StringBuilder();
using (var sw = new StringWriter(sb))
{
using (var tw = new HtmlTextWriter(sw))
{
vp.RenderControl(tw);
}
}
return sb.ToString();
}
}
may or may not be of use in this scenario, but worth a wee look..

ASP.NET MVC Use Controller or View outside of the MVC application context

Hello i am creating a small webpage that give our users an interface to search in our database.
This website must supply 2 webservice functions, Search(string searchString) and GetAccountInfoByInitials(string initials)
I would like to use my controllers to do this, but i can not find out how i can get the html out of a ViewResult.
I have tryed the following, but the result.ToString() only give me the string "System.Web.Mvc.ViewResult"
public class SearchService : ISearchService
{
private readonly ServiceHandlerController _controller;
public SearchService()
{
_controller = new ServiceHandlerController();
}
public string Search(string searchString)
{
var result = _controller.Search(searchString);
return result.ToString();
}
public string GetAccountInfoByInitials(string initials)
{
var result = _controller.Search(initials).ToString();
return result;
}
}
This is an answer to a question I posted similar to this one:
Is there a way to process an MVC view (aspx file) from a non-web application?
public class AspHost : MarshalByRefObject
{
public string _VirtualDir;
public string _PhysicalDir;
public string ViewToString<T>(string aspx, Dictionary<string, object> viewData, T model)
{
StringBuilder sb = new StringBuilder();
using (StringWriter sw = new StringWriter(sb))
{
using (HtmlTextWriter tw = new HtmlTextWriter(sw))
{
var workerRequest = new SimpleWorkerRequest(aspx, "", tw);
HttpContext.Current = new HttpContext(workerRequest);
ViewDataDictionary<T> viewDataDictionary = new ViewDataDictionary<T>(model);
foreach (KeyValuePair<string, object> pair in viewData)
{
viewDataDictionary.Add(pair.Key, pair.Value);
}
object view = BuildManager.CreateInstanceFromVirtualPath(aspx, typeof(object));
ViewPage viewPage = view as ViewPage;
if (viewPage != null)
{
viewPage.ViewData = viewDataDictionary;
}
else
{
ViewUserControl viewUserControl = view as ViewUserControl;
if (viewUserControl != null)
{
viewPage = new ViewPage();
viewPage.Controls.Add(viewUserControl);
}
}
if (viewPage != null)
{
HttpContext.Current.Server.Execute(viewPage, tw, true);
return sb.ToString();
}
throw new InvalidOperationException();
}
}
}
public static AspHost SetupFakeHttpContext(string physicalDir, string virtualDir)
{
return (AspHost)ApplicationHost.CreateApplicationHost(
typeof(AspHost), virtualDir, physicalDir);
}
}
Then, to render a file:
var host = AspHost.SetupFakeHttpContext("Path/To/Your/MvcApplication", "/");
var viewData = new ViewDataDictionary<SomeModelType>(){ Model = myModel };
String rendered = host.ViewToString("~/Views/MyView.aspx", new Dictionary<string, object>(viewData), viewData.Model);
I do this in almost an identical fashion but actually use the controller iteself to return a partialview to string.
i use the following extension method in my base controller:
public static class ExtensionMethods
{
public static string RenderPartialToString(this ControllerBase controller, string partialName, object model)
{
var vd = new ViewDataDictionary(controller.ViewData);
var vp = new ViewPage
{
ViewData = vd,
ViewContext = new ViewContext(),
Url = new UrlHelper(controller.ControllerContext.RequestContext)
};
ViewEngineResult result = ViewEngines
.Engines
.FindPartialView(controller.ControllerContext, partialName);
if (result.View == null)
{
throw new InvalidOperationException(
string.Format("The partial view '{0}' could not be found", partialName));
}
var partialPath = ((WebFormView)result.View).ViewPath;
vp.ViewData.Model = model;
Control control = vp.LoadControl(partialPath);
vp.Controls.Add(control);
var sb = new StringBuilder();
using (var sw = new StringWriter(sb))
{
using (var tw = new HtmlTextWriter(sw))
{
vp.RenderControl(tw);
}
}
return sb.ToString();
}
}
followed by then returning my partialview in the following fashion:
return Content(this.RenderPartialToString("myPartialView", myModel));
This should hopefully sort you out.
The View Result doesn't holds the page by itself. Asp.net MVC uses it, along with the View Engine configured to get the actual page.
You'll hit a roadblock if you are using the default view engine - see link text. Basically because the asp.net view engine is tied to the context. Other view engines won't give you this issue, but if the assets you are trying to reduce are already relying in the default view engine then that defeats the purpose. There are other ways around it, but I'm unsure how convenient those would be for you.

asp.net mvc 1.0 - how to render a partial view as a string

I need to render a partial view to a string within a controller action. I have the following sample code, but the ControllerContext.ParentActionViewContext does not seem to exist in mvc 1.0
// Get the IView of the PartialView object.
var view = PartialView("MyPartialView").View;
// Initialize a StringWriter for rendering the output.
var writer = new StringWriter();
// Do the actual rendering.
view.Render(ControllerContext.ParentActionViewContext, writer);
Any tips greatly appreciated.
Here's one way to achieve this. There's also a BlockRenderer in MvcContrib.
try this MVC v1.0 (an extension method that i use)
public static class Extensionmethods
{
public static string RenderPartialToString(this Controller controller, string partialName)
{
return RenderPartialToString(controller, partialName, new object());
}
public static string RenderPartialToString(this Controller controller, string partialName, object model)
{
var vd = new ViewDataDictionary(controller.ViewData);
var vp = new ViewPage
{
ViewData = vd,
ViewContext = new ViewContext(),
Url = new UrlHelper(controller.ControllerContext.RequestContext)
};
ViewEngineResult result = ViewEngines
.Engines
.FindPartialView(controller.ControllerContext, partialName);
if (result.View == null)
{
throw new InvalidOperationException(
string.Format("The partial view '{0}' could not be found", partialName));
}
var partialPath = ((WebFormView)result.View).ViewPath;
vp.ViewData.Model = model;
Control control = vp.LoadControl(partialPath);
vp.Controls.Add(control);
var sb = new StringBuilder();
using (var sw = new StringWriter(sb))
{
using (var tw = new HtmlTextWriter(sw))
{
vp.RenderControl(tw);
}
}
return sb.ToString();
}
}
usage:
....
string htmlBlock = this.RenderPartialToString("YourPartialView", model);
return htmlBlock;
i use this in a ton of controllers with 100% success...
jim

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