export function error(){
    alert('oops, an error');
}

var module = await JS.InvokeAsync<IJSObjectReference>("import", "./Panel.razor.js");
await module.InvokeVoidAsync("error");

Pages/Panel.razor
Pages/Panel.razor.js
Pages/Panel.razor.css

_module = await JS.InvokeAsync<IJSObjectReference>("import", "./_content/RazorClassLibrary/componentName.razor.js");

export function showPrompt(message) {
  return prompt(message, 'Type anything here');
}

@page "/call-js-example-6"
@implements IAsyncDisposable
@inject IJSRuntime JS

<h1>Call JS Example 6</h1>

<p>
    <button @onclick="TriggerPrompt">Trigger browser window prompt</button>
</p>

<p>
    @result
</p>

@code {
    private IJSObjectReference? module;
    private string? result;

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            module = await JS.InvokeAsync<IJSObjectReference>("import", 
                "./scripts.js");
        }
    }

    private async Task TriggerPrompt()
    {
        result = await Prompt("Provide some text");
    }

    public async ValueTask<string?> Prompt(string message) =>
        module is not null ? 
            await module.InvokeAsync<string>("showPrompt", message) : null;

    async ValueTask IAsyncDisposable.DisposeAsync()
    {
        if (module is not null)
        {
            await module.DisposeAsync();
        }
    }
}

<Application x:Class="WpfApplication1.App"
            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
            StartupUri="MainWindow.xaml">
   <Application.Resources>   
   </Application.Resources>
   <JumpList.JumpList>
       <JumpList ShowRecentCategory="True" />
   </JumpList.JumpList>
</Application>

using System;
using System.Runtime.InteropServices;
using Microsoft.Win32;

namespace Common.Files
{
  //from : http://www.devx.com/vb2themax/Tip/19554?type=kbArticle&trk=MSCP
  public class FileAssociation
  {
      const int ShcneAssocchanged = 0x8000000;
      const int ShcnfIdlist = 0;

      public static void CreateFileAssociation(
          string extension,
          string className,
          string description,
           string exeProgram)
      {
          // ensure that there is a leading dot
          if (extension.Substring(0, 1) != ".")
              extension = string.Format(".{0}", extension);

          try
          {
              if (IsAssociated(extension)) return;

              // create a value for this key that contains the classname
              using (var key1 = Registry.ClassesRoot.CreateSubKey(extension))
              {
                  if (key1 != null)
                  {
                      key1.SetValue("", className);
                      // create a new key for the Class name
                      using (var key2 = Registry.ClassesRoot.CreateSubKey(className))
                      {
                          if (key2 != null)
                          {
                              key2.SetValue("", description);
                              // associate the program to open the files with this extension
                              using (var key3 = Registry.ClassesRoot.CreateSubKey(string.Format(@"{0}\Shell\Open\Command", className)))
                              {
                                  if (key3 != null) key3.SetValue("", string.Format(@"{0} ""%1""", exeProgram));
                              }
                          }
                      }
                  }
              }

              // notify Windows that file associations have changed
              SHChangeNotify(ShcneAssocchanged, ShcnfIdlist, 0, 0);
          }
          catch (Exception ex)
          {
             //todo: log ...
          }
      }

      // Return true if extension already associated in registry
      public static bool IsAssociated(string extension)
      {
          return (Registry.ClassesRoot.OpenSubKey(extension, false) != null);
      }

      [DllImport("shell32.dll")]
      public static extern void SHChangeNotify(int wEventId, int uFlags, int dwItem1, int dwItem2);
  }
}

private static void createFileAssociation()
{
   var appPath = Assembly.GetExecutingAssembly().Location;
    FileAssociation.CreateFileAssociation(".xyz", "xyz", "xyz File",
              appPath
              );
}

    public partial class App
  {
      public App()
      {
          this.Startup += appStartup;
      }

      void appStartup(object sender, StartupEventArgs e)
      {
          if (e.Args.Any())
          {
              this.Properties["StartupFileName"] = e.Args[0];
          }
      }
  //...

var startupFileName = Application.Current.Properties["StartupFileName"];

var jumpList = JumpList.GetJumpList(App.Current);
var jumpPath = new JumpPath();
jumpPath.Path = "some path goes here....";
// If the CustomCategory property is null
// or Empty, the item is added to the Tasks category
jumpPath.CustomCategory = "Files";
JumpList.AddToRecentCategory(jumpPath);      
jumpList.Apply();

<Application x:Class="Win7Wpf4.App"
           xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
           xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
           StartupUri="MainWindow.xaml">
  <Application.Resources>       
  </Application.Resources>
  <JumpList.JumpList>
      <JumpList ShowRecentCategory="True">
          <JumpPath
               CustomCategory="Files"
               Path="Some path goes here..."
              />          
      </JumpList>
  </JumpList.JumpList>
</Application>

<form method="post" asp-action="UploadFiles" asp-controller="Home" enctype="multipart/form-data">
    <input type="file" name="files" webkitdirectory />
    <input type="submit" value="Upload" />
</form>

using System.Collections.Generic;
using System.IO;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace UploadFolderASPNETCore.Controllers
{
    public class HomeController : Controller
    {
        private readonly IWebHostEnvironment _environment;
        private const int MaxBufferSize = 0x10000;

        public HomeController(IWebHostEnvironment environment)
        {
            _environment = environment;
        }

        public IActionResult Index()
        {
            return View();
        }

        [HttpPost("[action]")]
        public async Task<IActionResult> UploadFiles(IList<IFormFile> files)
        {
            var uploadsRootFolder = Path.Combine(_environment.WebRootPath, "uploads");
            CreateDir(uploadsRootFolder);

            foreach (var file in files)
            {
                var dirPath = Path.GetDirectoryName(file.FileName);
                CreateDir(Path.Combine(uploadsRootFolder, dirPath));

                var filePath = Path.Combine(uploadsRootFolder, file.FileName);
                using (var fileStream = new FileStream(filePath, FileMode.Create,
                                                        FileAccess.Write,
                                                        FileShare.None,
                                                        MaxBufferSize,
                                                        useAsync: true
                                                        ))
                {
                    await file.CopyToAsync(fileStream);
                }
            }

            return RedirectToAction("Index");
        }

        private void CreateDir(string path)
        {
            if (!Directory.Exists(path))
            {
                Directory.CreateDirectory(path);
            }
        }
    }
}

@using Microsoft.Extensions.Logging
@inject ILogger<Error> Logger
@inject IJSRuntime jsRuntime

<CascadingValue Value="this">
    @ChildContent
</CascadingValue>

@code {
    [Parameter]
    public RenderFragment? ChildContent { get; set; }

    public void ProcessError(Exception ex)
    {
        Logger.LogError("Error:ProcessError - Type: {Type} Message: {Message}", 
            ex.GetType(), ex.Message);
        jsRuntime.ToastrError("متاسفانه خطایی رخ داد");
        //StateHasChanged();
    }
}

<Error>
    <Router ...>
        ...
    </Router>
</Error>

@code {
    [CascadingParameter]
    public Error? Error { get; set; }

    private void CreatePost()
    {
        try
        {           
           throw new InvalidOperationException("پست ساخته نشد!");            
        }
        catch (Exception ex)
        {
            Error?.ProcessError(ex);
        }
    }
}

    <div id="coursesSection" class="k-rtl k-header">
        <div class="box-col">
            <form id="myForm" data-role="validator" novalidate="novalidate">
                <h3>ثبت نام</h3>
                <ul>
                    <li>
                        <label for="Id">Id</label>
                        <span id="Id" data-bind="text:course.Id"></span>
                    </li>
                    <li>
                        <label for="UserName">نام</label>
                        <input type="text" id="UserName" name="UserName" class="k-textbox"
                               data-bind="value:course.UserName"
                               required />
                    </li>
                    <li>
                        <label for="CourseName">دوره</label>
                        <input type="text" dir="ltr" id="CourseName" name="CourseName" required
                               data-bind="value:course.CourseName" />
                        <span class="k-invalid-msg" data-for="CourseName"></span>
                    </li>
                    <li>
                        <label for="Credit">مبلغ پرداختی</label>
                        <input id="Credit" name="Credit" type="number" min="1000" max="6000"
                               required data-max-msg="عددی بین 1000 و 6000" dir="ltr"
                               data-bind="value:course.Credit"
                               class="k-textbox k-input" />
                        <span class="k-invalid-msg" data-for="Credit"></span>
                    </li>
                    <li>
                        <label for="Email">پست الکترونیک</label>
                        <input type="email" id="Email" dir="ltr" name="Email"
                               data-bind="value:course.Email"
                               required class="k-textbox" />
                    </li>
                    <li>
                        <label for="Tel">تلفن</label>
                        <input type="tel" id="Tel" name="Tel" dir="ltr" pattern="\d{8}"
                               required class="k-textbox"
                               data-bind="value:course.Tel"
                               data-pattern-msg="8 رقم" />
                    </li>
                    <li>
                        <input type="checkbox" name="Accept"
                               data-bind="checked:accepted"
                               required />
                        شرایط دوره را قبول دارم.
                        <span class="k-invalid-msg" data-for="Accept"></span>
                    </li>
                    <li>
                        <button class="k-button"
                                data-bind="enabled: accepted, click: doSave"
                                type="submit">
                            ارسال
                        </button>
                        <button class="k-button" data-bind="click: resetModel">از نو</button>
                    </li>
                </ul>
                <span id="doneMsg"></span>
            </form>
        </div>

    <div id="coursesSection" class="k-rtl k-header">
        <div class="box-col">
            <form id="myForm" data-role="validator" novalidate="novalidate">
                           <!--فرم بحث شده در ابتدای مطلب-->
            </form>
        </div>
        <div id="results">
            <table class="metrotable">
                <thead>
                    <tr>
                        <th>Id</th>
                        <th>نام</th>
                        <th>دوره</th>
                        <th>هزینه</th>
                        <th>ایمیل</th>
                        <th>تلفن</th>
                        <th></th>
                        <th></th>
                    </tr>
                </thead>
                <tbody data-template="row-template" data-bind="source: coursesDataSourceRows"></tbody>
                <tfoot data-template="footer-template" data-bind="source: this"></tfoot>
            </table>
            <script id="row-template" type="text/x-kendo-template">
                <tr>
                    <td data-bind="text: Id"></td>
                    <td data-bind="text: UserName"></td>
                    <td dir="ltr" data-bind="text: CourseName"></td>
                    <td>
                        #: kendo.toString(get("Credit"), "c0") #
                    </td>
                    <td data-bind="text: Email"></td>
                    <td data-bind="text: Tel"></td>
                    <td><button class="k-button" data-bind="click: deleteCourse">حذف</button></td>
                    <td><button class="k-button" data-bind="click: editCourse">ویرایش</button></td>
                </tr>
            </script>
            <script id="footer-template" type="text/x-kendo-template">
                <tr>
                    <td colspan="3"></td>
                    <td>
                        جمع کل: #: kendo.toString(totalPrice(), "c0") #
                    </td>
                    <td colspan="2"></td>
                    <td></td>
                    <td></td>
                </tr>
            </script>
        </div>
    </div>