Render Razor view to string in ASP.NET 5

Question

In previous versions of ASP.NET it was possible, although not very simple, to render Razor views as strings. The methods I\'ve seem are to use a fake controller, or also to

Answer 1

I use the following types injected from the IServiceProvider:

ICompositeViewEngine viewEngine;
ITempDataProvider tempDataProvider;
IHttpContextAccessor httpContextAccessor;

I render the content using the following method:

private async Task<string> RenderView(string path, ViewDataDictionary viewDataDictionary, ActionContext actionContext)
{
    using (var sw = new System.IO.StringWriter())
    {
        var viewResult = viewEngine.FindView(actionContext, path);

        var viewContext = new ViewContext(actionContext, viewResult.View, viewDataDictionary, new TempDataDictionary(httpContextAccessor, tempDataProvider), sw);

        await viewResult.View.RenderAsync(viewContext);
        sw.Flush();

        if (viewContext.ViewData != viewDataDictionary)
        {
            var keys = viewContext.ViewData.Keys.ToArray();
            foreach (var key in keys)
            {
                viewDataDictionary[key] = viewContext.ViewData[key];
            }
        }

        return sw.ToString();
    }
}

I call it like this:

var path = "~/Views/Home/Index.cshtml";
var viewDataDictionary = new ViewDataDictionary(new Microsoft.AspNet.Mvc.ModelBinding.EmptyModelMetadataProvider(), new Microsoft.AspNet.Mvc.ModelBinding.ModelStateDictionary());
var actionContext = new ActionContext(httpContextAccessor.HttpContext, new Microsoft.AspNet.Routing.RouteData(), new ActionDescriptor());
viewDataDictionary.Model = null;
var text = await RenderView(path, viewDataDictionary, actionContext);

Of course, my viewDataDictionary and actionContext variables are set by another method for encapsulation. A modification to the new ViewDataDictionary line can result in a typed Model being bound to your View if you choose.

This code uses heavy usings, I think I've listed them below. Otherwise, VS2015 is pretty good about finding them.

using Microsoft.AspNet.Mvc;
using Microsoft.AspNet.Mvc.Rendering;

This was written under beta-3; it still builds, but some things may change. I'll try to come back here to update if it does.

Answer 2

There is a solution that I've used an year ago. I'm not sure if there is a new/better way to do, but it solves the problem.

public string RenderViewToString(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();
     }
}