So I have something odd happening in a MVC3 layout I created. It's strongly typed to BaseVM. Every View model inherits from BaseVM. When I debug and step through the code and it it steps through my layout, the BaseVM model is not null and it calls a method to get the current year for the copyright in the footer. But as soon as I step to the bottom of the layout, it throws an exception back up where I was calling the property to get the year and suddenly the Model is null. Now this doesn't cause the application to show an error screen or message, but this exception gets logged every time the page is loaded. Here's a code sample:
public class BaseVM
{
public string CurrentYear
{
get
{
return DateTime.Today.Year.ToString();
}
}
public BaseVM()
{
}
}
public class PrelaunchReserveVM : BaseVM
{
public PrelaunchDTO Prelaunch { get; set; }
public PrelaunchReserveVM()
: this(new PrelaunchDTO()) { }
public PrelaunchReserveVM(PrelaunchDTO prelaunch)
: base()
{
this.Prelaunch = prelaunch;
}
}
The action in the controller:
public ActionResult Reserve()
{
return View("Reserve", new PrelaunchReserveVM(new PrelaunchDTO()));
}
The layout:
#model StickyThink.Models.VM.BaseVM
...
<div id="container">
<div id="main" role="main" style="padding: 0px; margin: 0px;">
#RenderBody()
</div>
</div>
<footer>
<div id="FooterPageContainer" class="center">
Copyright © #Model.CurrentYear ... All rights reserved.
</div>
</footer>
<!-- END: Add your site or application content here -->
#Html.Partial("_Scripts")
#RenderSection("scripts", false);
So it steps into #Model.CurrentYear and model is not null. Then it steps down to #RenderSection (to render some scripts from the view) and then an exception is thrown and #Model is null. Thoughts?
You need to pass Model as the 2nd parameter in #Html.Partial("_Scripts", Model).
If I had to take a wild guess, I think there is a problem with the content of the _Scripts partial. Maybe it needs the model #krillgar, but my guess onn that would be no. I would suggest moving the _Scripts partial to NOT be a partial and reference the scripts in the header like normal. I suspect that this exception will then shows its face earlier and help you find the problem, and the reason the Model becomes null is becuase of the type of exception. So if you move the _Scripts partial and have null earlier, you know this is the place to look.
Related
I have a Razor helper function that creates a re-usable HTML panel that saves me writing the same HTML over and over again.
#helper DefaultPanel(string panelTitle) {
<div class="panel">
<div class="panel-logo"><img src="/logo.png"></div>
<div class=panel-inner">
<p class="panel-title">#panelTitle</p>
<div class="panel-content">
/* Can I pass content to be rendered in here here? */
</div>
</div>
</div>
</div>
}
I'm wondering, is it possible to re-use this helper to fill .panel-content with more HTML to allow further flexibility and code reuse - similar to something like below:
#LayoutHelpers.DefaultPanel("Welcome back") {
<div class="panel-content-inner">
<p>Welcome back, please select from the following options</p>
Profile
My Defails
</div>
}
Whilst using .NET MVC I've noticed the Html.BeginForm() does a similar thing when wrapping the code within the #using statement within the Html.BeginForm declaration, like so:
#using (Html.BeginForm("Index", "Login", FormMethod.Post))
{
<div>This content gets rendered within the <form></form> markup.</div>
}
But can this done using #helper methods? If not, is it possible to create a HtmlHelper extension to do a similar thing the way the Html.BeginForm() method does?
You can do a very similar thing using the #section syntax as seen here
This seems like something that would be really useful to be able to do, and odd that there's no easy way to do it on a component level.
There are two ways to achieve the required functionality.
1. #helper
Create #helper which accepts whatever parameters you need plus a function (single object parameter, returns object):
#helper DefaultPanel(string panelTitle, Func<object, object> content)
{
<div class="panel">
<div class="panel-logo">
<img src="/logo.png" />
</div>
<div class="panel-inner">
<p class="panel-title">#panelTitle</p>
<div class="panel-content">
#content(null)
</div>
</div>
</div>
}
Usage:
#DefaultPanel("title",
#<div class="panel-content-inner">
<p>Welcome back, please select from the following options</p>
Profile
My Defails
</div>
)
Your function may also accepts parameters, example here.
2. HtmlHelper extension method
Add the following code anywhere in your project:
namespace System.Web.Mvc
{
public static class HtmlHelperExtensions
{
public static HtmlDefaultPanel DefaultPanel(this HtmlHelper html, string title)
{
html.ViewContext.Writer.Write(
"<div class=\"panel\">" +
"<div class=\"panel-inner\">" +
"<p class=\"panel-title\">" + title + "</p>" +
"<div class=\"panel-content\">"
);
return new HtmlDefaultPanel(html.ViewContext);
}
}
public class HtmlDefaultPanel : IDisposable
{
private readonly ViewContext _viewContext;
public HtmlDefaultPanel(ViewContext viewContext)
{
_viewContext = viewContext;
}
public void Dispose()
{
_viewContext.Writer.Write(
"</div>" +
"</div>" +
"</div>"
);
}
}
}
Usage:
#using (Html.DefaultPanel("title2"))
{
<div class="panel-content-inner">
<p>Welcome back, please select from the following options</p>
Profile
My Defails
</div>
}
The extension method writes directly to the context. The trick is to return a disposable object, which Dispose method will be executed at the end of using block.
I don't know if #helper methods can do this but HtmlHelper extensions certainly can. You've mentioned the Html.BeginForm() example which is probably the most well known - all that does is return an object which implements IDisposable which means that when the Dispose() method is called it just calls the complimentary Html.EndForm() method to add the appropriate closing tags.
It would be very simple to do something similar for your HTML code. You can view the source code to the ASP.NET MVC HtmlHelpers at http://aspnetwebstack.codeplex.com/ - the BeginForm() code can be specifically be viewed here.
I'm working on setting up a shared content (navigation) for an asp.net MVC layout page.
Here is my partial view "_LayoutPartial.cshtml" with code to pull navigation data from a model.
#model MyApp.Models.ViewModel.LayoutViewModel
<p>
#foreach (var item in Model.navHeader)
{
//Test dump of navigation data
#Html.Encode(item.Name);
#Html.Encode(item.URL);
}
</p>
Here is how the code for my controller "LayoutController.cs" looks like.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MyApp.Models.ViewModel;
namespace MyApp.Controllers
{
public class LayoutController : Controller
{
//
// GET: /Layout/
LayoutViewModel layout = new LayoutViewModel();
public ActionResult Index()
{
return View(layout);
}
}
}
Here is the code for the "_Layout.cshtml" page. I'm attempting to call the partial view here using Html.RenderAction(Action,Controller) method.
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
</head>
<body>
<p>
#{Html.RenderAction("Index","Layout");}
</p>
#RenderBody()
</body>
</html>
When the layout page executes the #{Html.RenderAction("Index","Layout");} line, it throws out an error message "Error executing child request for handler 'System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper'."
What am I missing friends? How can I call a partial view in a layout page?
Thank you all in advance!
Instead of:
public ActionResult Index()
{
return View(layout);
}
do:
public ActionResult Index()
{
return PartialView(layout);
}
If you don't do that when you return a normal view from your child action, this normal view attempts to include the Layout, which in turn attempts to render the child action, which in turn returns a view, which in turn includes the Layout, which in turn attempts to render the child action, ... and we end up with names like the one ported by this very same site.
Also in your partial you don't need to do double encoding. The # Razor function already does HTML encode:
#model MyApp.Models.ViewModel.LayoutViewModel
<p>
#foreach (var item in Model.navHeader)
{
#item.Name
#item.URL
}
</p>
First verify that your child view is inside the Shared directory
#Html.Partial("_LayoutPartial")
OR
#{Html.RenderAction("actionname", "controller name");}
And don't use #Html.Encode(), Razor is already doing for u. Just use
#item.Name
#item.URL
I have solved this error getting on Layout page
System.Web.Mvc.HttpHandlerUtil+ServerExecuteHttpHandlerAsyncWrapper
Important !
First create partial view inside shared folder
In Controller ,
public PartialViewResult Userdetails()
{
....
return PartialView("PartialViewName", obj);
}
In Layout Page,
#{Html.RenderAction("action","controller");}
I know this is an old question but I thought I would throw this in here. You can use either Html.Action or Html.RenderAction. They both technically do the same thing but depending on how much content you're returning back can have an impact on which one you should really use for best efficiency.
Both of the methods allow you to call into an action method from a view and output the results of the action in place within the view. The difference between the two is that Html.RenderAction will render the result directly to the Response (which is more efficient if the action returns a large amount of HTML) whereas Html.Action returns a string with the result.
Source
I have a MVC3 view that enables the user to create a couple different things. Within the parent view the forms to do so are broken up via jquery ui tabs like the following:
<div id="tabs">
<ul>
<li>New Thing 1</li>
<li>Different New Thing</li>
</ul>
<div id="tabs-1">#Html.Action("CreateNewThing", "NewThingController")</div>
<div id="tabs-2">#Html.Action("CreateDifferentThing", "DifferentThing")</div>
<div></div>
</div>
<script type="text/javascript">
$(function () {
$("#tabs").tabs();
});
</script>
Within the partial view I have:
#model NewThingViewModel
#using (Html.BeginForm("CreateNewThing", "NewThingController", FormMethod.Post, new { id = "frmCreateNewThing" }))
{
...
with input fields, a submit button, etc. This seems to work well: it renders everything and posts just fine to the right controller action method.
However I'm now wiring in the validation and I've got an issue.
In the controller it is rendering the view like so:
public ActionResult CreateNewThing(NewThingViewModel model)
{
... initializing model fields, drop downs etc.
return PartialView("CreateNewThing", model);
}
I have a seperate post method like so:
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult CreateNewThing(NewThingViewModel newThingViewModel, FormCollection collection)
{
.....
}
Sample Model:
public class NewThingViewModel
{
[Required]
[StringLength(50)]
[Display(Name = "Display Name:")]
public string DisplayName { get; set; }
}
The trouble is, when the page first comes up the fields marked as [Required] through DataAnnotations in the model are showing up red as well as the validation summary showing them invalid when the page initially shows. I.E. it's acting like it's already been posted before the user gets to enter anything on the initial load or even put anything in the text boxes.
I know the first non-post CreateNewThing is firing because I can catch it in the debugger and I know the 2nd one does not on the initial load.
What would cause my validations to fire on the Get?
Is it due to the way Html.Action works and the fact that I'm rendering partial views onto another view?
I'm using UnobtrusiveJavaScriptEnabled and ClientValidationEnabled = true in web.config.
I can't find anyone else that has run into this particular problem. Every other example just seems to work, then again I don't find an example where the view is broken into three partials contained within jquery ui tabs.
How do I fix this?
Options:
Do I need to manually manipulate the Model.IsValid as a workaround?
Use a different mechanism to render the partial views on the parent view instead of Html.Action?
Use some javascript/jquery to catch the validation and stop it?
Don't have method parameters on your GET controller action. You can initialize an empty model and pass it to the view but you dont need a model to be passed into the method
You're passing in an "empty" model (which I assume has default values set for your required properties), when you should be passing in null.
I used the following tutorial to help me build an RSS Reader in my ASP.NET MVC3 Razor application:
http://weblogs.asp.net/jalpeshpvadgama/archive/2011/08/17/creating-basic-rss-reader-in-asp-net-mvc-3.aspx
However, unlike the tutorial example, I want the RSS feed to be displayed on every page, and have therefore added it to my layout file, /Views/Shared/_Layout.cshtml
I currently only have 2 views on my site, and to get the RSS Reader to work on both views I've got the following code in my HomeController:
public class HomeController : Controller
{
//
// GET: /Index/
public ActionResult Index()
{
return View(CT.Models.RssReader.GetRssFeed());
}
public ActionResult About()
{
return View(CT.Models.RssReader.GetRssFeed());
}
}
From my WebForms experience, I would simply add the RSS Reader code in my master page code behind, and it would automatically work on every page.
Is there a Controller for layout pages which allows me to do the same?
How can I get this to work on every call of the layout page, without having to return anything?
EDIT: Following #Sebastian's advice, I've now added this code to a Partial View, removed CT.Models.RssReader.GetRssFeed() from return View() and included this in my layout file:
#Html.Partial("_MyPartialView")
The code in this partial view is:
<ul>
#foreach (var item in Model)
{
<li>
#item.Title
</li>
}
</ul>
However, I'm not getting a runtime error:
Object reference not set to an instance of an object.
It's erroring on the line #foreach (var item in Model)
You have to create a partial view and add functionality there.
Then in your layout, render this partial.
EDIT
Is your partial view really a partial view? The reason I said that is because you have "_" in front of the name which suggests that it might be a layout (might just be a naming convention).
To fix object reference error, you have to add the #Model declaration on top of your partial view.
Hope it helps.
UPDATE
In order to use different model in partial view, you need to explicitly declare which model you are going to use on render partialmethod.
#{Html.RenderPartial("../YourFeed", Model.YourFeedModel);}
Let me know if that resolved your issue.
The new error you are having is due to you not passing a Model to the partial view. You can do this with the second argument of the Html.Partial function...
Html.Partial("ViewName", MyModel);
As I think you are trying to do this in a Layout page you could also consider using a static reference to get your RSS feed. So forget about needing to pass in a Model and in your partial have:
#foreach (var item in RssRepository.GetFeed())
{
<li>
#item.Title
</li>
}
this like to a class something like...
public static RssRepository
{
public static MyModel GetFeed()
{
return new MyModel();//<- return what you would normally pass as a Model for RSS feeds
}
}
Hope that all makes sense
I am new to MVC3 and Razor.
I have an "attention banner" on the master page as a Partial View that I want to "acknowledge" with a click on a link to close the banner (without reloading the page). I believe I need to use jQuery and an Ajax call, but I just can't seem to find the right combination.
Here is part of my _Layout.cshtml:
<section id="main">
<span id="attentionBar">#{ Html.RenderPartial("_AttentionBarPartial"); }</span>
#RenderBody()
</section>
This is my Partial View (just using Session as a shortcut for now to get it to work). I'm not sure what to use as the "link" to reload the view:
#{ this.Layout = null;}
#if(! String.IsNullOrWhiteSpace(#Session["Attention"].ToString()))
{
<div class="attentionPanel">
<span class="attentionLabel">Attention</span>
#Session["Attention"].ToString()
<span class="attentionLabel">
#* WHAT DO I PUT HERE *#
#Ajax.ActionLink("X", "AcknowledgeAttentionBar", "Home", new AjaxOptions{ UpdateTargetId="attentionPanel", InsertionMode=InsertionMode.Replace })
</span>
</div>
}
Here is my Home controller. Again, I am not sure that the code is quite correct, but essentially I will clear out the condition that shows the attention banner.
public class HomeController : Controller
{
public ActionResult Index()
{
ViewBag.Message = "Home Controller Updated At " + DateTime.Now.ToLongDateString()
+ " " + DateTime.Now.ToLongTimeString();
return View();
}
public PartialViewResult AcknowledgeAttentionBar()
{
Session["Attention"] = String.Empty;
return PartialView("_AttentionBarPartial");
}
}
2 things:
Make sure you have included the jquery.unobtrusive-ajax.js script to your page in order for Ajax.ActionLink helper to work and send an AJAX request when the link is clicked instead of a normal redirect:
<script src="#Url.Content("~/Scripts/jquery.unobtrusive-ajax.js")" type="text/javascript"></script>
In your AjaxOptions you have specified UpdateTargetId="attentionPanel" but there's no element in your markup with id="attentionPanel". You have a div with class="attentionPanel" but that's not the same thing. On the other hand you have wrapped your banner in a <span id="attentionBar">, so you probably meant UpdateTargetId="attentionBar".