C# Render Partial View Without Controller

Question

I am having trouble using "RenderPartialViewToString" without a controller class.

I am currently having to create HTML within application start up which requires making a model, making a view and turning the view in to a HTML string.

Within my view it uses HTML Helper function/extension which seems to only be there if a controller is there.

Can anyone shed some light on how I can do this?

Answer 1

Razor.Parse is deprecated now. With version 3.5 of the Razor engine you would follow the steps outlined here: https://antaris.github.io/RazorEngine/Upgrading.html

The text below is copied verbatim from the above link:

var result = Razor.Parse(razorTemplate, model, cache_name)

is now either (when the modeltype is known or you want to precompile on startup)

// Once at startup (not required when using an ITemplateManager which knows how to resolve cache_name)
Engine.Razor.AddTemplate(cache_name, razorTemplate)
// On startup
Engine.Razor.Compile(cache_name, typeof(MyModel) /* or model.GetType() or null for 'dynamic'*/)

// instead of the Razor.Parse call
var result = Engine.Razor.Run(cache_name, typeof(MyModel) /* or model.GetType() or null for 'dynamic'*/, model)

or (when you want lazy compilation, like Parse)

// Once at startup (not required when using an ITemplateManager which knows how to resolve cache_name)
Engine.Razor.AddTemplate(cache_name, razorTemplate)

// instead of the Razor.Parse call
var result = Engine.Razor.RunCompile(cache_name, typeof(MyModel) /* or model.GetType() or null for 'dynamic'*/, model)

The semantic equivalent one-liner would be (only to be used to get started with RazorEngine quickly):

// This will just call AddTemplate for you (every time), note that the ITemplateManager has to support AddTemplate
// and it has to handle multiple calls to AddTemplate gracefully to make this work.
// The default implementation will throw an exception when you use the same cache_name for different templates.
var result = Engine.Razor.RunCompile(razorTemplate, cache_name, model.GetType() /* typeof(MyModel) or or null for 'dynamic'*/, model

Answer 2

You couldn't use html helper without current controller context.Try this extensions for render view into html

public static class RenderViewHelper
{
    public static string RenderPartialToString(string viewPath, object model)
    {
        string viewAbsolutePath = MapPath(viewPath);

        var viewSource = File.ReadAllText(viewAbsolutePath);

        string renderedText = Razor.Parse(viewSource, model);
        return renderedText;
    }

    public static string RenderPartialToString(ControllerContext context, string partialViewName, object model)
    {
        ViewEngineResult result = ViewEngines.Engines.FindPartialView(context, partialViewName);

        var viewData = new ViewDataDictionary() { Model = model };

        if (result.View != null)
        {
            var sb = new StringBuilder();

            using (var sw = new StringWriter(sb))
            {
                using (var output = new HtmlTextWriter(sw))
                {
                    var viewContext = new ViewContext(context, result.View, viewData, new TempDataDictionary(), output);
                    result.View.Render(viewContext, output);
                }
            }

            return sb.ToString();
        }

        return string.Empty;
    }

    public static string MapPath(string filePath)
    {
        return HttpContext.Current != null ? HttpContext.Current.Server.MapPath(filePath) : string.Format("{0}{1}", AppDomain.CurrentDomain.BaseDirectory, filePath.Replace("~", string.Empty).TrimStart('/'));
    }
}

First method used razor engine library. Second work with controller context.