Sample Code Error

mlcmds · October 25th, 2012, 05:08 AM

While running the sample code for this chapter after installing Nuget Package Wrox.ProMvc4.Views.SpecifyingViews, I get an error while navigation to Sample/PartialViewDemo.

Unhandled exception at line 4, column 5 in http://localhost:9725/Sample/partialviewdemo

The value of the property $ is null or undefined.

Can you help me understand the Javascript which raised this error

Balachander

szozz · October 31st, 2012, 03:29 PM

The error is because partialViewDemo is writing script into the body and executing it before jQuery is loaded.

Views/_viewStart.cshtml defines the Layout as discussed in the book. In Views/Shared/_Layout.cshtml

Code:

@Scripts.Render("~/bundles/jquery")

is at the bottom of the page. Move it to to the <head> section of the document so jQuery is available before the script (in the body) executes.

There are other "more correct" ways of accomplishing same, but this will get you through the sample.

mlcmds · October 31st, 2012, 11:19 PM

Quote:

Originally Posted by szozz

The error is because partialViewDemo is writing script into the body and executing it before jQuery is loaded.

Views/_viewStart.cshtml defines the Layout as discussed in the book. In Views/Shared/_Layout.cshtml

Code:

@Scripts.Render("~/bundles/jquery")

is at the bottom of the page. Move it to to the <head> section of the document so jQuery is available before the script (in the body) executes.

There are other "more correct" ways of accomplishing same, but this will get you through the sample.

Thanks szozz... It solved the problem.

Cheers

Balachander

Notso · May 9th, 2013, 09:57 PM

Hello,
I had to do the same thing to fix the partialviewdemo. However, that and the book do not explain how the partialviewdemo action works.

The book just discusses this part

Code:

        
public ActionResult Message() {
            ViewBag.Message = "This is a partial view.";
            return PartialView();
        }

It does not explain how that works with

Code:

        
public ActionResult PartialViewDemo() {
            return View();
        }

How does the partialViewDemo method know to use the actionResult Message? Couldn't it just as easily assume to use one of the others like Index2?

It really seems to me that partialViewDemo should return a blank view (with just the stuff from _Layout.cshtml) since there is no code in the method defining the ViewBag.Message or anything. Can someone explain this?

Tineler · June 4th, 2013, 03:10 PM

Quote:

Originally Posted by Notso

Hello,
I had to do the same thing to fix the partialviewdemo. However, that and the book do not explain how the partialviewdemo action works.

The book just discusses this part

Code:

        
public ActionResult Message() {
            ViewBag.Message = "This is a partial view.";
            return PartialView();
        }

It does not explain how that works with

Code:

        
public ActionResult PartialViewDemo() {
            return View();
        }

How does the partialViewDemo method know to use the actionResult Message? Couldn't it just as easily assume to use one of the others like Index2?

It really seems to me that partialViewDemo should return a blank view (with just the stuff from _Layout.cshtml) since there is no code in the method defining the ViewBag.Message or anything. Can someone explain this?

You have to look into the PartialViewDemo.cshtml

Code:

<div id="result"></div>

<script type="text/javascript">
    $(function () {
        $('#result').load('/sample/message');
    });
</script>

As you see the HTML of "/sample/message" will be loaded into the result div.

So, at first the controller executes the "PartialViewDemo()"-Action, which returns the HTML-Code shown above. But during loading the page, the JavaScript requests the HTML of "/sample/message". Now the controller executes "Message()", which returns the partial view and the JavaScript loads this into the div.

I hope this is explained clearly :-)

Cheers.