Basically, .net core is not the same as aspnetcore. They are different runtimes and thus, different downloads.

To get the approprirate aspnetcore.app 3.1.X version, try this microsoft download

If you still get the error, you may also need the corresponding .net core runtime

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Not completely. To  perform a websocket handshake , one needs HTTP. Once the handshake is successful, you can switch to websockets entirely. If your app runs in a browser, you may also need to serve a HTML/JavaScript file(s) for the landing page, which will require HTTP.

What are the advantages and disadvantages of this solution?

Advantages

• Full Duplex, stateful communication (unlike HTTP).
• Real server push (you can easily notify clients) .
• Add a layer on top of WebSockets (e.g. json rpc), and you can outperform HTTP.

Disadvantages

• Bare bones TCP, so your  app may require another protocol on top of that. Which could affect performance and reliability. Especially if you want to mix textual content (e.g. json) with binary content (e.g. images). You may end up reinventing the HTTP protocol over websockets.
• Not as many tools as for HTTP

What about Socket.io?

1. Socket.io was designed to handle some shortcomings of websockets.
2. Addresses Connection dropping issues with WebSockets.
3. Old Browser Fallback capability.

The post WebSockets–versus HTTP appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Quick Recap – Two types of threads for an ASP.NET programmer

1. Regular Windows Systems thread

2. .NET App Pool threads – Same thread pool that ASP.NET itself uses to process requests.   You would use a  ThreadPool.QueueUserWorkItem to use such a thread for your server side task – and yes, you would be taking away some of ASP.NET’s resources that it needs to do request processing.

How many concurrent ASP.NET requests per CPU?

UP from 12 requests per CPU (in .NET 3.5 and below),  there’s now 5,000 concurrent requests per CPU in ASP.NET 4 (and above).

Why use Async at all ?

Assume we have three operations – which take 100, 200 and 300 milliseconds respectively. With the synchronous call, total response time would be slightly more than 600 milliseconds. However, if the calls are made asynchronously, total response time would be slightly more than 300 milliseconds, because that is the duration of longest task/operation.

When to use Async ?

   Anytime that your server side ASP.NET code is making a database call, or a web service call or a network call or talking to the file system, that can be done asynchronously.

While that operation is in progress ASP.NET doesn’t have to be consuming a thread which is a CPU resource on that box while that operation is taking place.

And then once the operation is finished, ASP.NET will do the work to bring that request (rehydrate it), and then let it proceed with the result.

When NOT to use Async? – IIS versus Database Bottlenecks

The IIS thread pool can often handle many more simultaneous blocking requests than a database server. If the database is the bottleneck, asynchronous calls will not speed up the database response. Without a throttling mechanism, efficiently dispatching more work to an overwhelmed database server by using asynchronous calls merely shifts more of the burden to the database. If your DB is the bottleneck, asynchronous calls won’t be the magic bullet.

MultiThreading versus Async

Multithreading could encompass many more scenarios than Async. Typically Async is a request-response model where the response is delayed.

Multithreading could mean – do more than one task – without any consideration to the results (for e.g.  – a certain thread could be used for a fire and forget task).

What about Async and Await ?

Formalizes how non-blocking methods work in .NET.

The post Using Asynchronous methods in .NET–Quick Notes appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

1. Offline Data Persistence
2. InLine Grid Editing

Offline Persistence

Your kendo grid still displays data in case of a missing network connection to the datasource (using the offlineStorage option to enable offline storage). The DataSource uses this value as a key when saving and loading its state. By default, the Kendo UI DataSource uses the localStorage option to persist its offline state.

In Line Editing

A common scenario is to toggle a grid cell into edit mode by simply clicking on the Edit row button – and update the data inside the cell. This is trivial to accomplish in the kendo grid by simply adding the .Editable property to the grid

<%: Html.Kendo().Grid<Kendo.Mvc.Examples.Models.ProductViewModel>()
        .Name("grid")
        .Columns(columns =>
        {
            columns.Bound(p => p.ProductName);
            columns.Bound(p => p.UnitPrice).Width(120);
            columns.Bound(p => p.UnitsInStock).Width(120);
            columns.Bound(p => p.Discontinued).Width(120);
            columns.Command(command => { command.Edit(); command.Destroy(); }).Width(250);
        }).Editable(editable => editable.Mode(GridEditMode.InLine))

Excel style filtering

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Fire up Programs and Features then click on Turn Windows features on or off on the left side then select Internet Information Services\World Wide Web Services\Health and Diagnostics\HTTP Logging

Location of Log files

%SystemDrive%\inetpub\logs\LogFiles

OR

C:\Windows\system32\LogFiles\W3SVC1

The post Enable IIS logging appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Enter the OBJECT tag – a life saver. Basically, the object tag can host any binary object (in this case, a pdf file). All I had to do was call a URL action (GeneratePDF) from within this tag as shown below.

            <object id=‘pdfbox’ style=“width: 500px; height: 600px; overflow: hidden” type=“application/pdf” data=“@Url.Action(“GeneratePDF“, “Results“, new { id= @ViewBag.ID })”></object>

The controller needs to return a FILE object (created from the PDF byte stream). The object tag is smart enough to figure out that this is a PDF file (if you have pdf reader on your box) – and render it as such. Here are the different snippets of code to make this work.

Controller (PDF Generator)

  public ActionResult GeneratePDF(string id)
        {
           // This is just how I retrieved the pdf from a web service api. This could be a filesystem read for your use case 
            var api = new ResultsApi(http://……api/);
            dynamic apiResultPdf = null;
            try
            {
                apiResultPdf = api.QueryResultsPostDynamic(ConstructPdfLookupQuery(id));
            }
            catch (Exception e)
            {
                @ViewBag.Message = "The result service timed out!";
                return View("Error");
            }
            var deserializedResult = JsonConvert.DeserializeObject(apiResultPdf.ToString());


          // return a File action to the object tag
            return File(deserializedResult.pdf, "application/pdf");
        }

Index.cshtml

<input type='button' data-toggle=\'modal\' url='GetPdfResult?id=#=ID#' class='btn btn-primary' value='Pdf' data-modal-id='popupwindow' />




<script>  $(document).on('click', '#resultsgrid .btn-primary', function (e) {
      var foo;
      var origFocus = document.activeElement;
      e.preventDefault();
      var btn = $(this);

      btn.text('Fetching...');

      var url = $(this).attr('url');

      if (url.indexOf('#') == 0) {
          $(url).modal('open');
      } else {
          $.get(url, function (data) {
               foo = $('<div class="modal fade" id="modalfade" aria-hidden="true" tabindex="-1" role="dialog">' + data + '</div>').modal();
          }).success(function () { $('input:text:visible:first').focus(); });
      }

  });
  </script>



Popup.cshtml 

<style>
    /*.row {
        line-height:24pt;
        border: solid 1px black;
    }*/


    .modal-body {
        width: 600px;
        margin: 0 auto;
    }

    #pdfbox {
        width: 700px;
        height: 700px;
        border: 5px solid #ccc;
    }
</style>

<div class="modal-dialog" id="application-attribute-modal-edit">
    <div class="modal-content">
        <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×;</button>
 
            <h4 class="modal-title">Report ID = @ViewBag.ID</h4>
        </div>

        <div class="modal-body row">
            <object id='pdfbox' style="width: 500px; height: 600px; overflow: hidden" type="application/pdf" data="@Url.Action("GeneratePDF", "Results", new { id= @ViewBag.ID })"></object>
        
        </div>
    </div>
</div>

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Controls not showing up

(e.g. Html.Kendo().DropDownList() appears as a text box instead of a dropdown). To figure out the underlying issue, CTRL-SHFT-J on your browser to see the javascript errors. Chances are it will be something along the lines of ‘ kendogrid is not a function ‘ or ‘ kendo something is not a function’

To fix this, check the script library includes. They need to be in the following order:

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/jquery.min.js")"></script>

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/kendo.all.min.js")"></script>

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/kendo.aspnetmvc.min.js")"></script>

JQuery Conflicts

If you are using jquery bundles, they need to appear AFTER the kendo jquery references. E.g.

<!DOCTYPE html>

<html>

<head>

    <meta charset="utf-8" />

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/jquery.min.js")"></script>

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/kendo.all.min.js")"></script>

<script src="@Url.Content("~/Scripts/kendo/2015.1.429/kendo.aspnetmvc.min.js")"></script>

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

<body>

<div class="box-body">

<div class="col-lg-12">

<div class="form-group" id="experience-grid">

@(Html.Kendo().Grid(Model).Name("grid").Columns(columns =>....

</body>

</html>

Summary

These are some commonly encountered issues with Telerik’s Kendo UI for MVC. Powerful stuff, but can kill your afternoon if you are not aware of what goes where.

The post Some telerik kendo mvc script issues appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

MetadataException: Unable to load the specified metadata resource

The Solution:

The following res: (resource) references need to point to your newly placed model

<add name=”Entities” connectionString=”metadata=

    res://*/Models.MyModelName.csdl|

    res://*/Models.MyModelName.ssdl|

    res://*/Models.MyModelName.msl;

You do not need to fully qualify the namespace –the relative folder path (Models…) is all that is needed.

The post MetadataException: Unable to load the specified metadata resource appeared first on Anuj Varma, Hands-On Technology Architect, Clean Air Activist.

Server Error in ‘/’ Application. /Views/Index.cshtml cannot be found

Solution

Project Properties –> Web –> Specific Page – CLEAR the URL !

That fixes it.

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