Where should I include a script for a view compone

问题:

I have tried adding a section script inside a view component's view.

@section scripts {
    <script src="~/somepath" asp-append-version="true"></script>
}

I also have the Render Section in the shared layout

@RenderSection("scripts", required: false)

When used in partial views and elsewhere in the project the script loads fine. However when in a View Component the script does not load.

I suppose I could include the script in the section tag of every view that calls the component. I feel this does not fit with the self contained nature of a view component.

Is there another way I can do this?

回答1:

I also had problems with sections tag in viewcomponents. Turns out, to the best of my knowledge, there is no support for it in viewcomponents. See https://github.com/aspnet/Home/issues/2037

Jake Shakesworth has implemented a tag helper as shown in: Javascript in a View Component

On the other hand you could just include it in your viewcomponent as an

<script defer src"...">
  </script>

My requirement was to show a google map from a viewcomponent. Problem was that the script was getting called before the jquery, jquery.ui stuff.
By using defer you are telling the parser not to execute it until the document had loaded thus avoiding the problem of the having to put it in the layout for proper execution. Defer is supported by chrome, safari, and ie(10+), ff(3.6+), o(15+)

Hope this helps

This is an example of my code:

@using MobileVet.WebApp.Services;
@inject ISettingsService SettingsService
@{
     var Options = SettingsService.Value();

    <!--Service Area-->
    <div class="container-fluid">
         <div class="row p-3">
            <!--First column-->
            <div class="col-md-3">
                <h5 class="title">Site Navigation</h5>
                <ul>
                    <li><a href="#!">Home</a></li>
                    <li><a href="#!">Services</a></li>
                    <li><a href="#!">Link 3</a></li>
                    <li><a href="#!">Link 4</a></li>
                </ul> 

            </div>
            <!--/.First column-->
            <hr class="w-100 clearfix d-md-none">

            <!--Second column-->
            <div class="col-md-9">

                <div id="map-canvas" style="min-height: 300px; min-width: 200px;"> 
                </div>
            </div>
            <!--/.Second column-->

        </div>
    </div>
    <!--Service Area-->


<script src="http://maps.google.com/maps/api/js?key=XXXXXXXXXXXXXXXXXXXXXXX&sensor=false"></script>
<script type="text/javascript" src="~/js/components/servicearea.js" defer ></script>

}

Note that you would probably need to write some logic to prevent the script to be included multiple times if the view component is present more than once on a page, which was not my case

回答2:

From what I have seen, a "@section Scripts {}" in a ViewComponent is ignored and does not render in the relevant @RenderSection() of the ViewComponents _*layout.cshtml

Why that is I do not know.

回答3:

This is how I approached inserting scripts into a view component using Asp.net core 2.0.

First I created a partial view which I placed inside of the view components view folder.

Path: Views/Shared/Components/CalendarWidget/_CalendarScriptsPartial.cshtml

_CalendarScriptsPartial.cshtml

<environment include="Development">
    <script src="~/lib/jquery/dist/jquery.js"></script>
    <script src="~/lib/moment/moment.js"></script>
    <script src="~/lib/fullcalendar/dist/fullcalendar.js"></script>
    <script src="~/js/calendarWidget.js"></script>
</environment>
<environment exclude="Development">
    <script src="~/lib/jquery/dist/jquery.min.js"></script>
    <script src="~/lib/moment/min/moment.min.js"></script>
    <script src="~/lib/fullcalendar/dist/fullcalendar.min.js"></script>
    <script src="~/js/calendarWidget.js"></script>
</environment>

Then, I brought in the scripts via the Html partial async helper method inside of my view components view.

Path: Views/Shared/Components/CalendarWidget/Default.cshtml

Default.cshtml

<section id="calendar"></section>
@await Html.PartialAsync( "Components/CalendarWidget/_CalendarScriptsPartial" )

And for the sake of completeness here is my view components class.

Path: ViewComponents/CalendarWidgetViewComponent.cs

CalendarWidgetViewComponent.cs

using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;

namespace LodgersChoice.ViewComponents
{
    public class CalendarWidgetViewComponent : ViewComponent
    {
        public async Task<IViewComponentResult> InvokeAsync( )
        {
            return View( );
        }
    }
}

Note: Async isn't currently required in my example but I intend to inject a repository into the ctor of the class which will be using async/await.

Note 2: Once I'm done developing this I plan on bundling and minifying everything down to one script.

回答4:

@section scripts { } in viewcomponents is ignored and not rendered by Asp.Net rendering engine. So just use at the end of the view component. Also if your jquery scripts are at specified at the end in your layout, then jquery will not be available in your viewcomponents. Of course moving the jquery script to the head section in layout will solve the problem but it is recommended to load the js files at the end.

So if you want to keep jquery scripts at the end of layout and still use jquery in viewcomponents, you could use javascript domcontentloaded and any jquery can be written inside domcontentloaded. Not a permanent good approach but works for me.

<script>
    document.addEventListener('DOMContentLoaded', function (event) {
        console.log($ === jQuery)
    });
</script>

Or as mentioned by @Alberto L. Bonfiglio you could also try to move your script to another JS file and defer load it in your viewcomponent:

<script src="viewComponentScript.js" defer></script>

回答5:

View component in ASP.NET Core acts like independent view with separated controller, so you can insert bellow tag above of your view component

@{
Layout = null;
}

after that insert bellow tag to use related script,for example:

<environment include="Development">

<script src="~/js/chart.js"></script>

</environment>
 <environment exclude="Development">

<script src="~/js/chart.min.js"></script>

</environment>