public class EntityConfigurations
    {
        internal static void LoadEntityConfigurations(Assembly[] asm, DbModelBuilder modelBuilder)
        {
            if (asm == null) throw new ArgumentNullException(nameof(asm));

            foreach (var configurations in asm.Select(assembly => assembly.GetTypes()
                    .Where(
                     type => type.BaseType != null &&
                     type.BaseType.IsGenericType &&
                     type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>))
                    .ToList()))
            {
                configurations.ForEach(type =>
                {
                    dynamic instance = Activator.CreateInstance(type);
                    modelBuilder.Configurations.Add(instance);
                });
            }
        }
    }

/// <summary>
        /// 
        /// </summary>
        /// <param name="modelBuilder"></param>
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            EntityConfigurations.LoadEntityConfigurations(AppDomain.CurrentDomain.GetAssemblies(), modelBuilder);
        }

namespace CS11Tests;

public class StaticAbstractMembers
{
    public static void Test()
    {
        var sum = AddAll(new[] { 1, 2, 3, 4 });
        Console.WriteLine(sum);
    }

    private static int AddAll(int[] values)
    {
        int result = 0;
        foreach (var value in values)
        {
            result += value;
        }
        return result;
    }
}

var sum = AddAll(new[] { 1, 2, 3, 4, 0.68 });

Argument 1: cannot convert from 'double[]' to 'int[]' [CS11Tests]csharp(CS1503)

private static T AddAll<T>(T[] values)
    {
        T result = 0;
        foreach (var value in values)
        {
            result += value;
        }
        return result;
    }

T result = T.Zero;

using System.Numerics;

namespace CS11Tests;

public class StaticAbstractMembers
{
    public static void Test()
    {
        //var sum = AddAll(new[] { 1, 2, 3, 4 });
        var sum = AddAll(new[] { 1, 2, 3, 4, 0.68 });
        Console.WriteLine(sum);
    }

    private static T AddAll<T>(T[] values) where T : INumber<T>
    {
        T result = T.Zero;
        foreach (var value in values)
        {
            result += value;
        }
        return result;
    }
}

abstract static TSelf One { get; }
abstract static TSelf Zero { get; }

abstract static TResult operator +(TSelf left, TOther right);

public interface ISport
{
    bool IsTeamSport();
}

public class Swimming : ISport
{
    public bool IsTeamSport() => false;
}

public class Football : ISport
{
    public bool IsTeamSport() => true;
}

public class StaticAbstractMembers
{
    public static void Display<T>(T sport) where T : ISport
    {
        Console.WriteLine("Is Team Sport:" + sport.IsTeamSport());
    }
}

Display(new Football());

public interface ISport
{
    static abstract bool IsTeamSport();
}

public class Swimming : ISport
{
    public static bool IsTeamSport() => false;
}

public class Football : ISport
{
    public static bool IsTeamSport() => true;
}

public class StaticAbstractMembers
{
    public static void Display<T>() where T : ISport
    {
        Console.WriteLine("Is Team Sport:" + T.IsTeamSport());
    }
}

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.html;
using iTextSharp.text.html.simpleparser;
using iTextSharp.text.pdf;

namespace CustomHtmlWorkerTag
{
    /// <summary>
    /// Our custom HTML Tag to add an IElement.
    /// </summary>
    public class CustomImageHTMLTagProcessor : IHTMLTagProcessor
    {
        /// <summary>
        /// Tells the HTMLWorker what to do when a close tag is encountered.
        /// </summary>
        public void EndElement(HTMLWorker worker, string tag)
        {
        }

        /// <summary>
        /// Tells the HTMLWorker what to do when an open tag is encountered.
        /// </summary>
        public void StartElement(HTMLWorker worker, string tag, IDictionary<string, string> attrs)
        {
            Image image;
            var src = attrs["src"];

            if (src.StartsWith("data:image/"))
            {
                // data:[<MIME-type>][;charset=<encoding>][;base64],<data>
                var base64Data = src.Substring(src.IndexOf(",") + 1);
                var imagedata = Convert.FromBase64String(base64Data);
                image = Image.GetInstance(imagedata);
            }
            else
            {
                image = Image.GetInstance(src);
            }

            worker.UpdateChain(tag, attrs);
            worker.ProcessImage(image, attrs);
            worker.UpdateChain(tag);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            using (var pdfDoc = new Document(PageSize.A4))
            {
                PdfWriter.GetInstance(pdfDoc, new FileStream("Test.pdf", FileMode.Create));
                pdfDoc.Open();

                FontFactory.Register("c:\\windows\\fonts\\tahoma.ttf");

                var tags = new HTMLTagProcessors();
                // Replace the built-in image processor
                tags[HtmlTags.IMG] = new CustomImageHTMLTagProcessor();

                var html = "<img alt='' src='data:image/png;base64,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' />";

                var styles = new StyleSheet();
                styles.LoadTagStyle(HtmlTags.BODY, HtmlTags.FONTFAMILY, "tahoma");
                styles.LoadTagStyle(HtmlTags.BODY, HtmlTags.ENCODING, "Identity-H");

                PdfPCell pdfCell = new PdfPCell { Border = 0 };
                pdfCell.RunDirection = PdfWriter.RUN_DIRECTION_LTR;

                using (var reader = new StringReader(html))
                {
                    var parsedHtmlElements = HTMLWorker.ParseToList(reader, styles, tags, null);

                    foreach (var htmlElement in parsedHtmlElements)
                    {
                        pdfCell.AddElement(htmlElement);
                    }
                }

                var table1 = new PdfPTable(1);
                table1.AddCell(pdfCell);
                pdfDoc.Add(table1);
            }

            Process.Start("Test.pdf");
        }
    }
}

var tags = new HTMLTagProcessors();
// Replace the built-in image processor
tags[HtmlTags.IMG] = new CustomImageHTMLTagProcessor();

HTMLWorker.ParseToList(reader, styles, tags, null)

1. صفحات مصر یا Persistent Page
2. صفحات رویدادگرا یا Events Pages

"background": {
    "scripts": ["background.js"],
    "persistent": false
}

        public string TestNoneAsync()
        {
            var webClient = new WebClient();
            return webClient.DownloadString("http://www.google.com");
        }

        public void TestAsync()
        {
            var webClient = new WebClient();
            webClient.DownloadStringAsync(new Uri("http://www.google.com"));
            webClient.DownloadStringCompleted += webClientDownloadStringCompleted;
        }

        void webClientDownloadStringCompleted(object sender, DownloadStringCompletedEventArgs e)
        {
            // use e.Result
        }

using System;
using System.Linq;
using System.Net;
using System.Windows.Forms;

namespace Async02
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnGetInfo_Click(object sender, EventArgs e)
        {
            var req = (HttpWebRequest)WebRequest.Create("http://www.google.com");
            req.Method = "HEAD";
            req.BeginGetResponse(
                asyncResult =>
                {
                    var resp = (HttpWebResponse)req.EndGetResponse(asyncResult);
                    var headersText = formatHeaders(resp.Headers);
                    txtResults.Text = headersText;
                }, null);
        }

        private string formatHeaders(WebHeaderCollection headers)
        {
            var headerString = headers.Keys.Cast<string>()
                                      .Select(header => string.Format("{0}:{1}", header, headers[header]));
            return string.Join(Environment.NewLine, headerString.ToArray());
        }
    }
}

 An exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll but was not handled in user code
Additional information: Cross-thread operation not valid: Control 'txtResults' accessed from a thread other than the thread it was created on.

        private void btnGetInfo_Click(object sender, EventArgs e)
        {
            var sync = SynchronizationContext.Current;
            var req = (HttpWebRequest)WebRequest.Create("http://www.google.com");
            req.Method = "HEAD";
            req.BeginGetResponse(
                asyncResult =>
                {
                    var resp = (HttpWebResponse)req.EndGetResponse(asyncResult);
                    var headersText = formatHeaders(resp.Headers);
                    sync.Post(delegate { txtResults.Text = headersText; }, null);
                }, null);
        }

using System;
using System.Threading.Tasks;

namespace Async01
{
    public class AsyncExample
    {
        public async Task DoWorkAsync(int parameter)
        {
            await Task.Delay(parameter);
            Console.WriteLine(parameter);
        }
    }
}

        public async Task<double> GetNumberAsync()
        {
            var generator = new Random();
            await Task.Delay(generator.Next(1000));

            return generator.NextDouble();
        }

        public async Task<double> GetSumAsync()
        {
            var leftOperand = await GetNumberAsync();
            var rightOperand = await GetNumberAsync();

            return leftOperand + rightOperand;
        }

        public async Task<double> GetProductOfSumAsync()
        {
            var leftOperand = GetSumAsync();
            var rightOperand = GetSumAsync();

            return await leftOperand * await rightOperand;
        }

 Operator '*' cannot be applied to operands of type 'System.Threading.Tasks.Task<double>' and 'System.Threading.Tasks.Task<double>'

        public async Task<string> DownloadAsync()
        {
            var webClient = new WebClient();
            return await webClient.DownloadStringTaskAsync("http://www.google.com");
        }

        public void TestDownloadAsync()
        {
            Debug.WriteLine("Before DownloadAsync");
            DownloadAsync();
            Debug.WriteLine("After DownloadAsync");
        }

 Before DownloadAsync
After DownloadAsync

 PM> Install-Package Microsoft.Bcl.Async