public void ConfigureServices(IServiceCollection services)
 {
     services.AddControllers()
            .AddNewtonsoftJson()
     // ...
}

public class Person
{
   public string FirstName { get; set; }
   public string LastName { get; set; }
   public DateTime? BirthDay { get; set; }
}

using System;
using System.Text.Json.Serialization;

namespace ConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            Person person = JsonSerializer.Parse<Person>(...);
            string json = JsonSerializer.ToString(person);
        }
    }
}

namespace System.Text.Json.Serialization
{
    public static class JsonSerializer
    {
        public static object Parse(ReadOnlySpan<byte> utf8Json, Type returnType, JsonSerializerOptions options = null);
        public static object Parse(string json, Type returnType, JsonSerializerOptions options = null);
        public static TValue Parse<TValue>(ReadOnlySpan<byte> utf8Json, JsonSerializerOptions options = null);
        public static TValue Parse<TValue>(string json, JsonSerializerOptions options = null);

        public static string ToString(object value, Type type, JsonSerializerOptions options = null);
        public static string ToString<TValue>(TValue value, JsonSerializerOptions options = null);
    }
}

public sealed class JsonSerializerOptions
{
   public bool AllowTrailingCommas { get; set; }
   public int DefaultBufferSize { get; set; }
   public JsonNamingPolicy DictionaryKeyPolicy { get; set; }
   public bool IgnoreNullValues { get; set; }
   public bool IgnoreReadOnlyProperties { get; set; }
   public int MaxDepth { get; set; }
   public bool PropertyNameCaseInsensitive { get; set; }
   public JsonNamingPolicy PropertyNamingPolicy { get; set; }
   public JsonCommentHandling ReadCommentHandling { get; set; }
   public bool WriteIndented { get; set; }
}

// Json.NET:
var settings = new JsonSerializerSettings
{
    NullValueHandling = NullValueHandling.Ignore
};
string json = JsonConvert.SerializeObject(person, settings);

// JsonSerializer:
var options = new JsonSerializerOptions
{
    IgnoreNullValues = true
};
string json = JsonSerializer.ToString(person, options);

services.AddControllers()
   .AddJsonOptions(options => options.JsonSerializerOptions.WriteIndented = true);

[JsonPropertyName("birthdate")]
public DateTime? BirthDay { get; set; }

var options = new JsonSerializerOptions
{
   PropertyNamingPolicy = JsonNamingPolicy.CamelCase
};
string json = JsonSerializer.ToString(person, options);

var store = GetStore();
string postCode = null;
if (store != null && store.Address != null && store.Address.PostCode != null)
     postCode = store.Address.PostCode.ToString();

• این متد فقط با انواع ارجاعی (reference types)  کار می‌کند و می‌بایست برای کار با انواع مقداری (value types) اصلاح شود.
  
• با انواع داده ای مثل string چه باید کرد؟ در مورد این نوع داده‌ها تنها مطمئن شدن از null نبودن کافی نیست. برای مثال در مورد string ، گاهی اوقات ما می‌خواهیم از خالی نبودن آن نیز مطمئن شویم. و یا در مورد collection‌ها تنها null نبودن کافی نیست بلکه زمانی که نیاز به محاسبه مجموع و یا یافتن بزرگترین عضو است، باید از خالی نبودن مجموعه و وجود حداقل یک عضو در آن مطمئن باشیم.
  

CREATE TABLE Data 
(
id INTEGER NOT NULL PRIMARY KEY IDENTITY,
data VARCHAR(50) NOT NULL
);

INSERT INTO Data
VALUES ('~!hasan @#$%^&*(reza)[ali]^^^^^^^^'),
('(Ja[][][]va~!@#$*d-mohammad)'),
('Mohammad'), ('Maryam');

CREATE TABLE Unwanted
(
id INT NOT NULL PRIMARY KEY IDENTITY, 
chars CHAR(1) NOT NULL UNIQUE
);

INSERT Unwanted 
VALUES ('~'),('!'),('@'),('#'),('$'),('%'),
('['),(']'),('^'),('&'),('*');

WITH pre AS
(
SELECT ROW_NUMBER() OVER(ORDER BY id) AS id, chars
  FROM Unwanted
),
 cte AS
(
SELECT  data.id,
        nbr,
        CAST(Data AS VARCHAR(50)) AS Data
  FROM Data
       CROSS JOIN (SELECT COUNT(*) AS nbr FROM Unwanted)t
 WHERE EXISTS
       (SELECT *
          FROM Unwanted
         WHERE Data LIKE '%#' + chars + '%' ESCAPE '#')
 
 UNION ALL
  
 SELECT C.id,
        nbr - 1,
        CAST(REPLACE(C.data, U.chars, '') AS VARCHAR(50))
   FROM cte AS C
        INNER JOIN pre U
        ON C.nbr = U.id
  WHERE nbr > 0
)
SELECT data
  FROM cte
 WHERE nbr = 0
 
 UNION ALL
  
SELECT data
  FROM Data
 WHERE NOT EXISTS
       (SELECT id           
          FROM cte
         WHERE cte.id = data.id);

using System;
using iTextSharp.text;
using PdfRpt.Core.Contracts;
using PdfRpt.Core.Helper;
using PdfRpt.FluentInterface;

namespace PdfReportSamples.CustomCellTemplate
{
    public class CustomCellTemplatePdfReport
    {
        public IPdfReportData CreatePdfReport()
        {
            return new PdfReport().DocumentPreferences(doc =>
            {
                doc.RunDirection(PdfRunDirection.RightToLeft);
                doc.Orientation(PageOrientation.Portrait);
                doc.PageSize(PdfPageSize.A4);
                doc.DocumentMetadata(new DocumentMetadata { Author = "Vahid", Application = "PdfRpt", Keywords = "Test", Subject = "Test Rpt", Title = "Test" });
                doc.Compression(new CompressionSettings
                               {
                                   CompressionLevel = CompressionLevel.BestCompression,
                                   EnableCompression = true
                               });
            })
             .DefaultFonts(fonts =>
             {
                 fonts.Path(AppPath.ApplicationPath + "\\fonts\\irsans.ttf",
                            Environment.GetEnvironmentVariable("SystemRoot") + "\\fonts\\verdana.ttf");
             })
             .PagesFooter(footer =>
             {
                 footer.DefaultFooter(DateTime.Now.ToString("MM/dd/yyyy"));
             })
             .PagesHeader(header =>
             {
                 header.DefaultHeader(defaultHeader =>
                 {
                     defaultHeader.ImagePath(AppPath.ApplicationPath + "\\Images\\01.png");
                     defaultHeader.Message("گزارش جدید ما");
                 });
             })
             .MainTableTemplate(template =>
             {
                 template.BasicTemplate(BasicTemplate.SnowyPineTemplate);
             })
             .MainTablePreferences(table =>
             {
                 table.ColumnsWidthsType(TableColumnWidthType.Relative);
                 table.MultipleColumnsPerPage(new MultipleColumnsPerPage
                 {
                     ColumnsGap = 20,
                     ColumnsPerPage = 2,
                     ColumnsWidth = 250,
                     IsRightToLeft = true,
                     TopMargin = 7
                 });
             })
             .MainTableDataSource(dataSource =>
             {
                 var table = new System.Data.DataTable("لیست حقوق");
                 table.Columns.Add("شخص", typeof(string));
                 table.Columns.Add("ماه", typeof(int));
                 table.Columns.Add("مبلغ", typeof(decimal));

                 var rnd = new Random();
                 for (int i = 0; i < 200; i++)
                     table.Rows.Add("شخص " + i, rnd.Next(1, 12), rnd.Next(400, 2000));

                 dataSource.DataTable(table);
             })
             .MainTableEvents(events =>
             {
                 events.DataSourceIsEmpty(message: "There is no data available to display.");
                 events.CellCreated(args =>
                     {
                         //change the background color of the cell based on the value
                         if (args.RowType == RowType.DataTableRow && args.Cell.RowData.Value != null && args.Cell.RowData.Value is decimal)
                         {
                             if ((decimal)args.Cell.RowData.Value <= 1000)
                                 args.Cell.BasicProperties.BackgroundColor = BaseColor.CYAN;
                         }
                     });
             })
             .MainTableSummarySettings(summary =>
             {
                 summary.OverallSummarySettings("جمع کل");
                 summary.PageSummarySettings("جمع صفحه");
                 summary.PreviousPageSummarySettings("نقل از ستون قبل");
             })
             .MainTableColumns(columns =>
             {
                 columns.AddColumn(column =>
                 {
                     column.PropertyName("rowNo");
                     column.IsRowNumber(true);
                     column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                     column.IsVisible(true);
                     column.Order(0);
                     column.Width(1);
                     column.HeaderCell("ردیف");
                 });

                 columns.AddColumn(column =>
                 {
                     column.PropertyName("شخص");
                     column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                     column.IsVisible(true);
                     column.Order(1);
                     column.Width(3);
                     column.HeaderCell("شخص");
                     column.ColumnItemsTemplate(t => t.CustomTemplate(new MyCustomCellTemplate()));
                 });

                 columns.AddColumn(column =>
                 {
                     column.PropertyName("ماه");
                     column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                     column.IsVisible(true);
                     column.Order(2);
                     column.Width(2);
                     column.HeaderCell("ماه");
                     column.ColumnItemsTemplate(template =>
                     {
                         template.TextBlock();
                         template.ConditionalFormatFormula(list =>
                         {
                             var cellValue = int.Parse(list.GetSafeStringValueOf("ماه", nullValue: "0"));
                             if (cellValue == 7)
                             {
                                 return new CellBasicProperties
                                 {
                                     PdfFontStyle = DocumentFontStyle.Bold | DocumentFontStyle.Underline,
                                     FontColor = new BaseColor(System.Drawing.Color.Brown),
                                     BackgroundColor = new BaseColor(System.Drawing.Color.Yellow)
                                 };
                             }
                             return new CellBasicProperties { PdfFontStyle = DocumentFontStyle.Normal };
                         });
                     });
                 });

                 columns.AddColumn(column =>
                 {
                     column.PropertyName("مبلغ");
                     column.CellsHorizontalAlignment(HorizontalAlignment.Center);
                     column.IsVisible(true);
                     column.Order(3);
                     column.Width(2);
                     column.HeaderCell("مبلغ");
                     column.ColumnItemsTemplate(template =>
                     {
                         template.TextBlock();
                         template.DisplayFormatFormula(obj => obj == null ? string.Empty : string.Format("{0:n0}", obj));
                     });
                     column.AggregateFunction(aggregateFunction =>
                     {
                         aggregateFunction.NumericAggregateFunction(AggregateFunction.Sum);
                         aggregateFunction.DisplayFormatFormula(obj => obj == null ? string.Empty : string.Format("{0:n0}", obj));
                     });
                 });
             })
             .Export(export =>
                 {
                     export.ToXml();
                     export.ToExcel();
                 })
             .Generate(data => data.AsPdfFile(AppPath.ApplicationPath + "\\Pdf\\RptDataTableSample.pdf"));
        }
    }
}

using System;
using System.Collections.Generic;
using iTextSharp.text;
using iTextSharp.text.pdf;
using PdfRpt.Core.Contracts;
using PdfRpt.Core.Helper;

namespace PdfReportSamples.CustomCellTemplate
{
    public class MyCustomCellTemplate : IColumnItemsTemplate
    {
        Random _rnd = new Random();

        public void CellRendered(PdfPCell cell, Rectangle position, PdfContentByte[] canvases, CellAttributes attributes)
        {
        }

        public CellBasicProperties BasicProperties { set; get; }
        public Func<IList<CellData>, CellBasicProperties> ConditionalFormatFormula { set; get; }

        public PdfPCell RenderingCell(CellAttributes attributes)
        {
            var pdfCell = new PdfPCell();
            var table = new PdfPTable(1) { RunDirection = PdfWriter.RUN_DIRECTION_RTL };

            var filePath = AppPath.ApplicationPath + "\\Images\\" + _rnd.Next(1, 5).ToString("00") + ".png";
            var photo = PdfImageHelper.GetITextSharpImageFromImageFile(filePath);
            table.AddCell(new PdfPCell(photo, fit: false)
            {
                Border = 0,                
                VerticalAlignment = Element.ALIGN_BOTTOM,
                HorizontalAlignment = Element.ALIGN_CENTER
            });

            var name = attributes.RowData.TableRowData.GetSafeStringValueOf("شخص");
            table.AddCell(new PdfPCell(attributes.BasicProperties.PdfFont.FontSelector.Process(name))
            {
                Border = 0,
                HorizontalAlignment = Element.ALIGN_CENTER
            });

            pdfCell.AddElement(table);

            return pdfCell;
        }
    }
}

events.CellCreated(args =>
    {
         //change the background color of the cell based on the value
         if (args.RowType == RowType.DataTableRow && args.Cell.RowData.Value != null && args.Cell.RowData.Value is decimal)
         {
              if ((decimal)args.Cell.RowData.Value <= 1000)
                   args.Cell.BasicProperties.BackgroundColor = BaseColor.CYAN;
          }
      });