Passing Local Variables to a View from Controller

Passing (local variable)ListCourses and showing the list at the view MVC

You are passing courseinfo which is List<Courses> but you your view is expecting the a model of type Project.Models.Courses.

If you still want to pass list of Courses then change the model in the view as below.

    @model List<Project.Models.Courses>

Also, when you want to access the properties of Model then you need iterate the list using foreach as below.

@foreach(var course in Model)
{
 <b>
                        <b>Course ID : @course.CourseID</b>
                        <b>Course ID : @course.Day</b>
                        <b>Course ID : @course.Hour</b>
                     </b> 
}

passing variable from controller to partial view rails

For passing instance variables to partials you can use the locals:

# view from
<%= render partial: 'skillsetdata', locals: { skills_set_data: @skillSetData } %>

While in the local you receive the value of that instance variable, which is now a local one:

# partial
<% skills_set_data.each do |single_skill| %>
  <option value="<%= single_skill.skillname %>">
    <%=single_skill.skillname %>
  </option>
<% end %>

Accessing controller data in order to pass local variables for rendering a haml partial in a view

As long as the data is available in your outer view, you can pass it to a partial using the locals option. For instance, if this was on your home page, you could pass the data to the controller like this...

# app/controllers/pages_controller.rb
class PagesController < ApplicationController
  def home
    @data = Model.get_data
  end
end

Then, in your view, pass that @data into your partial using the locals option of the render method:

# app/views/pages/home.html.erb
<%= render :partial => 'data_popups/events', :locals => { :data => @data } %>

Simple passing data from controller to view in c#

for a simple variable add it to the ViewBag and then reference it via @Model

for example

        public ActionResult Index()
        {

            var Home = "No place like";
            ViewBag.Home = Home;
            return View();
        }

In View:

@ViewBag.Home 

will display what you've set.

As you want to add more complex data structures you will want to pass through a model object to the view.

You can pass this like

    public ActionResult Index()
    {

        var myViewModel = new MyViewModel(); // set up view model with data

        return View(myViewModel);
    }

and then you can reference that from the view too!

{
    @model = MyViewModel;
}

and refer to it later

<p>@model.PropertyName</p>

passing variable from Controller to View

The code have various issues:

1. render() save the new View in a local var so that don't exists after the function end

2. You can't expect $this->showAddresses to have a value at the constructor time.

You should implement the render() method as a method outside of the View constructor.

function __construct() 
{
    parent::__construct();

    require 'view/head.php';

    $result = $this->showAddresses; // (NULL) The object is not created yet

    require 'view/foot.php';
}

View class:

public function factory($plik) // Old render($splik) method
{
    return new $plik();
}

addressesView class:

function __construct() 
{
  parent::__construct();
}

function render()
{
    require 'view/head.php';

    $result = $this->showAddresses; // Object is created and the field has a value

    require 'view/foot.php';
}

Controller class:

 $view = $this->view->factory('addressesView');
 $view->showAddresses = $this->model->getAddresses(); 
 $view->render();

Is it possible to render a partial by passing a local variable for the collection?

Please try it

<%= render partial: 'item_kanban', collection: items, as: :item %>

Now you can access

<%= link_to item, class: "list-group-item" do %>
  <%= item.number %>
<% end %>

When you did

<%= render partial: 'item_kanban', collection: items %> will give you a item_kanban local variable and not a item variable.

So you need to specify it by as: :item now you can access item

Views: is it better to set instance variables or pass in locals?

In Rails, it's best practice to pass the instance variables to your views. Rails developers are used to it, it's familiar, it's less typing, it works.

Yet, my personal preference is to pass locals to render because it makes your view variables more explicit. It also has a benefit of raising a "no method" exception if you mistype a variable rather than getting a "nil" exception when using instance vars.

I'm not sure there is going to be much difference in performance either way. Might be interesting running some benchmarks. But if you're using Rails, then view rendering speed is probably not your top concern.

Note that if you use an instance var in your controller to memoize a method's result (say to cache an expensive calculation), than that instance var "leaks" into your view. You probably didn't need it in your view, but you still get it (because Rails exposes any instance vars in controllers to your views). Thus, passing local vars is more explicit in communicating "my view relies on this variable")

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