How Asp.net Core displays a view

Question

How MVC 6 displays a view. What is the actual method in Razor ViewEngine that generates html output? Also, if possible, explain the process of visualizing the view.

Maybe you could point me to the file in the mvc source on github. thanks!

Answer 1

Here is the complete solution for what you are looking for. I used dependency injection to get the HtmlHelper in the controller. You can also add your own assistant if you wish.

using Microsoft.AspNet.Html.Abstractions; using Microsoft.AspNet.Mvc; using Microsoft.AspNet.Mvc.ModelBinding; using Microsoft.AspNet.Mvc.Rendering; using Microsoft.AspNet.Mvc.ViewEngines; using Microsoft.AspNet.Mvc.ViewFeatures; using Microsoft.AspNet.Mvc.ViewFeatures.Internal; using Microsoft.Extensions.WebEncoders; using System.ComponentModel.DataAnnotations; using System; public class MyController : Controller { private readonly IHtmlGenerator htmlGenerator; ICompositeViewEngine viewEngine; IModelMetadataProvider metadataProvider; private readonly IHtmlHelper helper; IHtmlEncoder htmlEncoder; IUrlEncoder urlEncoder; IJavaScriptStringEncoder javaScriptStringEncoder; public MyController(IHtmlHelper helper, IHtmlGenerator htmlGenerator, ICompositeViewEngine viewEngine, IModelMetadataProvider metadataProvider, IHtmlEncoder htmlEncoder, IUrlEncoder urlEncoder, IJavaScriptStringEncoder javaScriptStringEncoder) { this.htmlGenerator = htmlGenerator; this.viewEngine = viewEngine; this.metadataProvider = metadataProvider; this.htmlEncoder = htmlEncoder; this.urlEncoder = urlEncoder; this.javaScriptStringEncoder = javaScriptStringEncoder; this.helper = helper; } [HttpGet] public IActionResult MyHtmlGenerator() { MyViewModel temp = new MyViewModel(); var options = new HtmlHelperOptions(); options.ClientValidationEnabled = true; ViewDataDictionary<MyViewModel> dic = new ViewDataDictionary<MyViewModel>(this.metadataProvider, new ModelStateDictionary()); ViewContext cc = new ViewContext(ActionContext, new FakeView(), dic, TempData, TextWriter.Null, options); var type = typeof(MyViewModel); var metadata = this.metadataProvider.GetMetadataForType(type); ModelExplorer modelEx = new ModelExplorer(this.metadataProvider, metadata, temp); ViewData["Description"] = "test desc"; ViewData["Id"] = 1; this.ViewData = new ViewDataDictionary(this.metadataProvider, new ModelStateDictionary()); IHtmlHelper<MyViewModel> dd = new HtmlHelper<MyViewModel>(this.htmlGenerator, this.viewEngine, this.metadataProvider, this.htmlEncoder, this.urlEncoder, this.javaScriptStringEncoder); ((ICanHasViewContext)dd).Contextualize(cc); dd.ViewContext.ViewData = this.ViewData; var desc = GetString(dd.TextBoxFor(m => m.ID)); var ID = GetString(dd.TextBoxFor(m => m.Description)); // Do whatever you want with the ID and desc return new ContentResult() { Content = ID + desc }; } public static string GetString(IHtmlContent content) { var writer = new System.IO.StringWriter(); content.WriteTo(writer, new HtmlEncoder()); return writer.ToString(); } } public class MyViewModel : BaseAssetViewModel { // [RegularExpression(@"^-?\d{1,13}(\.\d{0,5})?$|^-?\.\d{1,5}$")] [Required] public int ID { get; set; } [MinLength(2)] public string Description { get; set; } // Property with no validation public string Other { get; set; } } public class FakeView : IView { string IView.Path { get { throw new NotImplementedException(); } } public Task RenderAsync(ViewContext viewContext) { throw new InvalidOperationException(); } Task IView.RenderAsync(ViewContext context) { throw new NotImplementedException(); } } 

Answer 2

I don’t know if this can be useful, maybe you should start looking for tag helpers:

https://github.com/DamianEdwards/TagHelperStarterWeb

they work differently to create assistants that integrate more naturally into the page.