PM> Install-Package Spire.XLS

using Spire.Xls;

namespace PrintOptions
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a workbook
            Workbook workbook = new Workbook();

            //Load an Excel document 
            workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");

            //Get the first worksheet
            Worksheet worksheet = workbook.Worksheets[0];

            //Get the PageSetup object of the first worksheet
            PageSetup pageSetup = worksheet.PageSetup;

            //Set page margins
            pageSetup.TopMargin = 0.3;
            pageSetup.BottomMargin = 0.3;
            pageSetup.LeftMargin = 0.3;
            pageSetup.RightMargin = 0.3;

            //Specify print area
            pageSetup.PrintArea = "A1:D10";

            //Specify title row
            pageSetup.PrintTitleRows = "$1:$2";

            //Allow to print with row/column headings
            pageSetup.IsPrintHeadings = true;

            //Allow to print with gridlines
            pageSetup.IsPrintGridlines = true;

            //Allow to print comments as displayed on worksheet
            pageSetup.PrintComments = PrintCommentType.InPlace;

            //Set printing quality (dpi)
            pageSetup.PrintQuality = 300;

            //Allow to print worksheet in black & white mode
            pageSetup.BlackAndWhite = true;

            //Set the printing order
            pageSetup.Order = OrderType.OverThenDown;

            //Fit worksheet on one page
            pageSetup.IsFitToPage = true;

            //Save the workbook
            workbook.SaveToFile("PagePrintOptions.xlsx", ExcelVersion.Version2016);
        }
    }
}

Imports Spire.Xls
 
Namespace PrintOptions
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a workbook
            Dim workbook As Workbook =  New Workbook() 
 
            'Load an Excel document 
            workbook.LoadFromFile("C:\Users\Administrator\Desktop\sample.xlsx")
 
            'Get the first worksheet
            Dim worksheet As Worksheet =  workbook.Worksheets(0) 
 
            'Get the PageSetup object of the first worksheet
            Dim pageSetup As PageSetup =  worksheet.PageSetup 
 
            'Set page margins
            pageSetup.TopMargin = 0.3
            pageSetup.BottomMargin = 0.3
            pageSetup.LeftMargin = 0.3
            pageSetup.RightMargin = 0.3
 
            'Specify print area
            pageSetup.PrintArea = "A1:D10"
 
            'Specify title row
            pageSetup.PrintTitleRows = "$1:$2"
 
            'Allow to print with row/column headings
            pageSetup.IsPrintHeadings = True
 
            'Allow to print with gridlines
            pageSetup.IsPrintGridlines = True
 
            'Allow to print comments as displayed on worksheet
            pageSetup.PrintComments = PrintCommentType.InPlace
 
            'Set printing quality (dpi)
            pageSetup.PrintQuality = 300
 
            'Allow to print worksheet in black & white mode
            pageSetup.BlackAndWhite = True
 
            'Set the printing order
            pageSetup.Order = OrderType.OverThenDown
 
            'Fit worksheet on one page
            pageSetup.IsFitToPage = True
 
            'Save the workbook
            workbook.SaveToFile("PagePrintOptions.xlsx", ExcelVersion.Version2016)
        End Sub
    End Class
End Namespace

using System;
using Spire.Xls;
using System.Drawing.Printing;
using System.Windows.Forms;

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

        private void button1_Click(object sender, EventArgs e)
        {
            //Create a Workbook object
            Workbook workbook = new Workbook();

            //Load an Excel file 
            workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");

            //Fit worksheet on one page    
            PageSetup pageSetup = workbook.Worksheets[0].PageSetup;
            pageSetup.IsFitToPage = true;

            //Create a PrintDialog object
            PrintDialog dialog = new PrintDialog();

            //Specify printer settings 
            dialog.AllowCurrentPage = true;
            dialog.AllowSomePages = true;
            dialog.AllowSelection = true;
            dialog.UseEXDialog = true;
            dialog.PrinterSettings.Duplex = Duplex.Simplex;

            //Apply the dialog to workbook 
            workbook.PrintDialog = dialog;

            //Create a PrintDocument object based on the workbook
            PrintDocument printDocument = workbook.PrintDocument;

            //Invoke the print dialog
            if (dialog.ShowDialog() == DialogResult.OK)
            {
                printDocument.Print();
            }
        }
    }
}

Imports System
Imports Spire.Xls
Imports System.Drawing.Printing
Imports System.Windows.Forms
 
Namespace PrintExcelUsingPrintDialog
    Public partial Class Form1
	 Inherits Form
        Public  Sub New()
            InitializeComponent()
        End Sub
 
        Private  Sub button1_Click(ByVal sender As Object, ByVal e As EventArgs)
            'Create a Workbook object
            Dim workbook As Workbook =  New Workbook() 
 
            'Load an Excel file 
            workbook.LoadFromFile("C:\Users\Administrator\Desktop\sample.xlsx")
 
            'Fit worksheet on one page    
            Dim pageSetup As PageSetup =  workbook.Worksheets(0).PageSetup 
            pageSetup.IsFitToPage = True
 
            'Create a PrintDialog object
            Dim dialog As PrintDialog =  New PrintDialog() 
 
            'Specify printer settings 
            dialog.AllowCurrentPage = True
            dialog.AllowSomePages = True
            dialog.AllowSelection = True
            dialog.UseEXDialog = True
            dialog.PrinterSettings.Duplex = Duplex.Simplex
 
            'Apply the dialog to workbook 
            workbook.PrintDialog = dialog
 
            'Create a PrintDocument object based on the workbook
            Dim printDocument As PrintDocument =  workbook.PrintDocument 
 
            'Invoke the print dialog
            If dialog.ShowDialog() = DialogResult.OK Then
                printDocument.Print()
            End If
        End Sub
    End Class
End Namespace

using Spire.Xls;
using System.Drawing.Printing;

namespace SilentlyPrint
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Workbook object
            Workbook workbook = new Workbook();

            //Load an Excel file
            workbook.LoadFromFile(@"C:\Users\Administrator\Desktop\sample.xlsx");

            //Fit worksheet on one page    
            PageSetup pageSetup = workbook.Worksheets[0].PageSetup;
            pageSetup.IsFitToPage = true;

            //Set the print controller to StandardPrintController, which will prevent print process from showing
            workbook.PrintDocument.PrintController = new StandardPrintController();

            //Get PrinterSettings from the workbook
            PrinterSettings settings = workbook.PrintDocument.PrinterSettings;

            //Specify printer name, duplex mode and print pages
            settings.PrinterName = "HP LaserJet P1007"; 
            settings.Duplex = Duplex.Simplex;
            settings.FromPage = 1;
            settings.ToPage = 3;         

            //Print the workbook
            workbook.PrintDocument.Print();
        }
    }
}

Imports Spire.Xls
Imports System.Drawing.Printing
 
Namespace SilentlyPrint
    Class Program
        Shared  Sub Main(ByVal args() As String)
            'Create a Workbook object
            Dim workbook As Workbook =  New Workbook() 
 
            'Load an Excel file
            workbook.LoadFromFile("C:\Users\Administrator\Desktop\sample.xlsx")
 
            'Fit worksheet on one page    
            Dim pageSetup As PageSetup =  workbook.Worksheets(0).PageSetup 
            pageSetup.IsFitToPage = True
 
            'Set the print controller to StandardPrintController, which will prevent print process from showing
            workbook.PrintDocument.PrintController = New StandardPrintController()
 
            'Get PrinterSettings from the workbook
            Dim settings As PrinterSettings =  workbook.PrintDocument.PrinterSettings 
 
            'Specify printer name, duplex mode and print pages
            settings.PrinterName = "HP LaserJet P1007" 
            settings.Duplex = Duplex.Simplex
            settings.FromPage = 1
            settings.ToPage = 3         
 
            'Print the workbook
            workbook.PrintDocument.Print()
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.PDF

using Spire.Pdf;

namespace GetNumberOfPages
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a PdfDocument object
            PdfDocument pdf = new PdfDocument();

            //Load a sample PDF file 
            pdf.LoadFromFile("Contract.pdf");

            //Count the number of pages in the PDF
            int PageNumber = pdf.Pages.Count;
            Console.WriteLine("The PDF file has {0} pages", PageNumber);

            //Close the PDF
            pdf.Close();
        }
    }
}