PM> Install-Package Spire.XLS

using Spire.Xls;
using Spire.Xls.Collections;
using Spire.Xls.Core;
using System.IO;
using System.Text;

namespace GetExcelProperties
{
    class Program
    {

        static void Main(string[] args)
        {
            {
                //Create a Workbook instance
                Workbook workbook = new Workbook();

                //Load a sample Excel file
                workbook.LoadFromFile("Budget Template.xlsx");

                //Create a StringBuilder instance
                StringBuilder sb = new StringBuilder();

                //Get a collection of all standard document properties
                BuiltInDocumentProperties standardProperties = workbook.DocumentProperties;

                //Get specific standard properties and append them to the StringBuilder instance
                sb.AppendLine("Standard Document Properties:");
                sb.AppendLine("Title: " + standardProperties.Title);
                sb.AppendLine("Subject: " + standardProperties.Subject);
                sb.AppendLine("Category: " + standardProperties.Category);
                sb.AppendLine("Keywords: " + standardProperties.Keywords);
                sb.AppendLine("Comments: " + standardProperties.Comments);
                sb.AppendLine();

                //Get a collection of all custom document properties
                ICustomDocumentProperties customProperties = workbook.CustomDocumentProperties;

                sb.AppendLine("Custom Document Properties:");
                //Iterate through the collection
                for (int i = 0; i < customProperties.Count; i++)
                {
                    //Get the name and value of each custom document property and append them to the StringBuilder instance
                    string name = customProperties[i].Name;
                    string value = customProperties[i].Value.ToString();
                    sb.AppendLine(name + ": " + value);
                }

                //Write the content of the StringBuilder instance into a text file
                File.WriteAllText("GetExcelProperties.txt", sb.ToString());            
            }
        }
    }
}

using Spire.Xls;
using Spire.Xls.Collections;
using Spire.Xls.Core;

namespace DeleteExcelProperties
{
    class Program
    {

        static void Main(string[] args)
        {
            {
                //Create a Workbook instance
                Workbook workbook = new Workbook();

                //Load a sample Excel file
                workbook.LoadFromFile("Budget Template.xlsx");

                //Get a collection of all standard document properties
                BuiltInDocumentProperties standardProperties = workbook.DocumentProperties;

                //Set the value of each standard document property as empty
                standardProperties.Title = "";
                standardProperties.Subject = "";
                standardProperties.Category = "";
                standardProperties.Keywords = "";
                standardProperties.Comments = "";
 
                //Get a collection of all custom document properties
                ICustomDocumentProperties customProperties = workbook.CustomDocumentProperties;

                //Iterate through the collection
                for (int i = customProperties.Count -1; i >=0; i--)
                {
                    //Delete each custom document property from the collection by its name
                    customProperties.Remove(customProperties[i].Name);

                }

                //Save the result file
                workbook.SaveToFile("DeleteDocumentProperties.xlsx", ExcelVersion.Version2016);            
            }
        }
    }
}

PM> Install-Package Spire.XLS

using Spire.Xls;

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

            //Load the original Excel document from file
            originalBook.LoadFromFile("Info.xlsx");

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

            //Get the header row
            CellRange headerRow = sheet.Range[1, 1, 1,5];

            //Get two cell ranges
            CellRange range1 = sheet.Range[2, 1, 6, sheet.LastColumn];
            CellRange range2 = sheet.Range[7, 1, sheet.LastRow, sheet.LastColumn];

            //Create a new workbook
            Workbook newBook1 = new Workbook();

            //Get the first worksheet of new workbook
            Worksheet newSheet1 = newBook1.Worksheets[0];

            //Copy the header row and range 1 to the first worksheet of the new workbook
            sheet.Copy(headerRow, newSheet1.Range[1, 1]);
            sheet.Copy(range1, newSheet1.Range[2, 1]);

            //Copy the column width from the original workbook to the new workbook
            for (int i = 0; (i < sheet.LastColumn); i++)
            {
                newBook1.Worksheets[0].SetColumnWidth(i + 1, sheet.GetColumnWidth(i + 1));
            }

            //Save the new workbook to an Excel file
            newBook1.SaveToFile("Sales Depart.xlsx", ExcelVersion.Version2016);

            //Create another new workbook
            Workbook newBook2 = new Workbook();

            //Get the first worksheet of new workbook
            Worksheet newSheet2 = newBook2.Worksheets[0];

            //Copy the header row and range 2 to the first worksheet of the new workbook
            sheet.Copy(headerRow, newSheet2.Range[1, 1]);
            sheet.Copy(range2, newSheet2.Range[2, 1]);

            //Copy the column width from the original workbook to the new workbook
            for (int i = 0; (i < sheet.LastColumn); i++)
            {
                newBook2.Worksheets[0].SetColumnWidth(i + 1, sheet.GetColumnWidth(i + 1));
            }

            //Save the new workbook to another Excel file
            newBook2.SaveToFile("Development Depart.xlsx", ExcelVersion.Version2016);

        }
    }
}

Imports Spire.XLS

Namespace splitworksheet
    Class Program
        Private Shared Sub Main(ByVal args() As String)
            'Create a Workbook instance 
            Dim originalBook As Workbook = New Workbook

            'Load the original Excel document from file
            originalBook.LoadFromFile("Info.xlsx")

            'Get the first worksheet
            Dim sheet As Worksheet = originalBook.Worksheets(0)

            'Get the header row
            Dim headerRow As CellRange = sheet.Range(1, 1, 1, 5)

            'Get two cell ranges
            Dim range1 As CellRange = sheet.Range(2, 1, 6, sheet.LastColumn)
            Dim range2 As CellRange = sheet.Range(7, 1, sheet.LastRow, sheet.LastColumn)

            'Create a new workbook
            Dim newBook1 As Workbook = New Workbook

            'Get the first worksheet of new workbook
            Dim newSheet1 As Worksheet = newBook1.Worksheets(0)

            'Copy the header row and range 1 to the first worksheet of the new workbook
            sheet.Copy(headerRow, newSheet1.Range(1, 1))
            sheet.Copy(range1, newSheet1.Range(2, 1))

            'Copy the column width from the original workbook to the new workbook
            Dim i As Integer = 0
            While (i < sheet.LastColumn)
                newBook1.Worksheets(0).SetColumnWidth(i + 1, sheet.GetColumnWidth(i + 1))
                i += 1
            End While

            'Save the new workbook to an Excel file
            newBook1.SaveToFile("Sales Depart.xlsx", ExcelVersion.Version2016)

            'Create another new workbook
            Dim newBook2 As Workbook = New Workbook

            'Get the first worksheet of new workbook
            Dim newSheet2 As Worksheet = newBook2.Worksheets(0)

            'Copy the header row and range 2 to the first worksheet of the new workbook
            sheet.Copy(headerRow, newSheet2.Range(1, 1))
            sheet.Copy(range2, newSheet2.Range(2, 1))

            'Copy the column width from the original workbook to the new workbook
            Dim i As Integer = 0
            While (i < sheet.LastColumn)
                newBook2.Worksheets(0).SetColumnWidth(i + 1, sheet.GetColumnWidth(i + 1))
                i += 1
            End While

            'Save the new workbook to another Excel file
            newBook2.SaveToFile("Development Depart.xlsx", ExcelVersion.Version2016)
        End Sub
    End Class
End Namespace

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.XLS

using Spire.Xls;
using System.Data;
using System.Drawing;

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

            // Access the first worksheet in the workbook
            Worksheet sheet = workbook.Worksheets[0];

            // Create and populate a DataTable with sample data
            DataTable dataTable = new DataTable("Data");
            dataTable.Columns.Add("ID", typeof(int));
            dataTable.Columns.Add("Name", typeof(string));
            dataTable.Columns.Add("Age", typeof(int));
            dataTable.Columns.Add("Country", typeof(string));
            dataTable.Columns.Add("Salary ($)", typeof(decimal));
            dataTable.Rows.Add(101, "John Smith", 28, "USA", 54000m);
            dataTable.Rows.Add(102, "Maria Garcia", 34, "Spain", 65500m);
            dataTable.Rows.Add(103, "Liam Johnson", 22, "Canada", 48000m);
            dataTable.Rows.Add(104, "Emma Brown", 30, "Australia", 72300m);
            dataTable.Rows.Add(105, "Wei Zhang", 40, "China", 58700m);
            dataTable.Rows.Add(106, "Sofia Lopez", 26, "Mexico", 45200m);

            // Insert data from the DataTable into the worksheet
            sheet.InsertDataTable(dataTable, true, 1, 1);

            // Format the worksheet
            // Style the header row
            sheet.Rows[0].Style.Color = Color.LightGreen;
            sheet.Rows[0].Style.Font.FontName = "Arial";
            sheet.Rows[0].Style.Font.Size = 12f;
            sheet.Rows[0].BorderAround(); // Apply borders around the header row
            sheet.Rows[0].Borders.Color = Color.Blue;

            // Style the data rows
            for (int i = 1; i < sheet.AllocatedRange.Rows.Count(); i++)
            {
                sheet.Rows[i].Style.Color = Color.LightGray;
                sheet.Rows[i].Style.Font.FontName = "Arial";
                sheet.Rows[i].Style.Font.Size = 11f;
            }

            // Adjust the column widths to fit the content
            for (int j = 1; j <= sheet.AllocatedRange.Columns.Count(); j++)
            {
                sheet.AutoFitColumn(j);
            }

            // Save the workbook to a memory stream
            MemoryStream stream = new MemoryStream();
            workbook.SaveToStream(stream, FileFormat.Version2016);

            // Write the stream content to a file
            File.WriteAllBytes("output/CreateExcelByStream.xlsx", stream.ToArray());

            // Release resources
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

namespace LoadExcelStream
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create an instance of the Workbook class
            Workbook workbook = new Workbook();

            // Create a memory stream
            MemoryStream stream = new MemoryStream();
            File.OpenRead("Sample.xlsx").CopyTo(stream);

            // Load the Excel file from the stream
            workbook.LoadFromStream(stream);

            // Access the first worksheet in the workbook
            Worksheet sheet = workbook.Worksheets[0];

            // Initialize a list to store the data retrieved from the worksheet
            List<List<string>> data = new List<List<string>>();
            for (int i = 0; i < sheet.AllocatedRange.Rows.Count(); i++)
            {
                // Create a list to hold each row of data
                List<string> lines = new List<string>();
                for (int j = 0; j < sheet.AllocatedRange.Columns.Count(); j++)
                {
                    // Retrieve the cell text and add it to the row
                    lines.Add(sheet.AllocatedRange[i + 1, j + 1].Text);
                }
                // Add the row to the data list
                data.Add(lines);
            }

            // Print the retrieved data or use it for further operations
            foreach (List<string> lines in data)
            {
                Console.WriteLine(string.Join(" | ", lines));
            }
        }
    }
}

using Spire.Xls;
using System.Drawing;

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

            // Create a memory stream
            MemoryStream stream = new MemoryStream();
            File.OpenRead("Sample.xlsx").CopyTo(stream);

            // Load the Excel file from the stream
            workbook.LoadFromStream(stream);

            // Access the first worksheet in the workbook
            Worksheet sheet = workbook.Worksheets[0];

            // Modify the style of the header row
            CellRange headerRow = sheet.AllocatedRange.Rows[0];
            headerRow.Style.Font.FontName = "Times New Roman";
            headerRow.Style.Font.Size = 12f;
            headerRow.Style.Color = Color.LightBlue;

            // Modify the style of the data rows
            for (int i = 1; i < sheet.AllocatedRange.Rows.Count(); i++)
            {
                CellRange dataRow = sheet.AllocatedRange.Rows[i];
                dataRow.Style.Font.FontName = "Arial";
                dataRow.Style.Font.Size = 10f;
                dataRow.Style.Color = Color.LightGray;
                // Alternate row coloring (even rows)
                if (i % 2 == 0)
                {
                    dataRow.Style.Color = Color.LightSlateGray;
                }
            }

            // Autofit columns to adjust their width based on content
            for (int k = 1; k <= sheet.AllocatedRange.Columns.Count(); k++)
            {
                sheet.AutoFitColumn(k);
            }

            // Change the border color
            sheet.AllocatedRange.Style.Borders.Color = Color.White;

            // Save the modified workbook back to the stream
            workbook.SaveToStream(stream);

            // Write the stream content to a new file
            File.WriteAllBytes("output/ModifyExcelByStream.xlsx", stream.ToArray());

            // Release resources
            workbook.Dispose();
        }
    }
}

PM> Install-Package Spire.XLS

using Spire.Xls;

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

            //Load a sample Excel document
            workbook.LoadFromFile("sample.xlsx");

            //Set built-in document properties for the Excel workbook
            workbook.DocumentProperties.Author = "E-iceblue Team";
            workbook.DocumentProperties.Title = "Add Built-in Document Properties in Excel ";
            workbook.DocumentProperties.Keywords = "Excel, Document Properties, C#, VB.NET";
            workbook.DocumentProperties.Category = "Spire.XLS Demo";
            workbook.DocumentProperties.Company = "E-iceblue";
            workbook.DocumentProperties.Comments = "Document properties are details about a file that describe or identify it.";

            //Save the result document
            workbook.SaveToFile("ExcelProperties.xlsx", FileFormat.Version2013);
        }
    }
}

Imports Spire.Xls

Namespace ExcelProperties
    Class Program
        Private Shared Sub Main(ByVal args() As String)
            'Create a Workbook object
            Dim workbook As Workbook = New Workbook

            'Load a sample Excel document
            workbook.LoadFromFile("sample.xlsx")

            'Set built-in document properties for the Excel workbook
            workbook.DocumentProperties.Author = "E-iceblue Team"
            workbook.DocumentProperties.Title = "Add Built-in Document Properties in Excel "
            workbook.DocumentProperties.Keywords = "Excel, Document Properties, C#, VB.NET"
            workbook.DocumentProperties.Category = "Spire.XLS Demo"
            workbook.DocumentProperties.Company = "E-iceblue"
            workbook.DocumentProperties.Comments = "Document properties are details about a file that describe or identify it."

            'Save the result document
            workbook.SaveToFile("ExcelProperties.xlsx", FileFormat.Version2013)
        End Sub
    End Class
End Namespace

using Spire.Xls;
using System;

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

            //Load a sample Excel document
            workbook.LoadFromFile("sample.xlsx");

            //Add custom document properties to the document
            workbook.CustomDocumentProperties.Add("_MarkAsFinal", true);
            workbook.CustomDocumentProperties.Add("The Editor", "E-iceblue");
            workbook.CustomDocumentProperties.Add("Phone Number", 12345678);
            workbook.CustomDocumentProperties.Add("Document ID", 1);
            workbook.CustomDocumentProperties.Add("Revision Date", DateTime.Now);

            //Save the result document
            workbook.SaveToFile("ExcelCustomProperties.xlsx", FileFormat.Version2013);
        }
    }
}

Imports Spire.Xls

Namespace CustomExcelProperties
    Class Program
        Private Shared Sub Main(ByVal args() As String)
            'Create a Workbook object
            Dim workbook As Workbook = New Workbook

            'Load a sample Excel document
            workbook.LoadFromFile("sample.xlsx")

            'Add custom document properties to the document
            workbook.CustomDocumentProperties.Add("_MarkAsFinal", True)
            workbook.CustomDocumentProperties.Add("The Editor", "E-iceblue")
            workbook.CustomDocumentProperties.Add("Phone Number", 12345678)
            workbook.CustomDocumentProperties.Add("Document ID", 1)
            workbook.CustomDocumentProperties.Add("Revision Date", DateTime.Now)

            'Save the result document
            workbook.SaveToFile("ExcelCustomProperties.xlsx", FileFormat.Version2013)
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.XLS

using Spire.Xls;

namespace MergeExcelFiles
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a string array from Excel file paths
            string[] inputFiles = new string[] { "April.xlsx", "May.xlsx", "June.xlsx" };

            //Initialize a new Workbook object
            Workbook newWorkbook = new Workbook();
            //Clear the default worksheets
            newWorkbook.Worksheets.Clear();

            //Initialize another temporary Workbook object
            Workbook tempWorkbook = new Workbook();

            //Loop through the string array
            foreach (string file in inputFiles)
            {
                //Load the current workbook
                tempWorkbook.LoadFromFile(file);
                //Loop through the worksheets in the current workbook
                foreach (Worksheet sheet in tempWorkbook.Worksheets)
                {
                    //Copy each worksheet from the current workbook to the new workbook
                    newWorkbook.Worksheets.AddCopy(sheet, WorksheetCopyType.CopyAll);
                }
            }

            //Save the new workbook to file
            newWorkbook.SaveToFile("MergeWorkbooks.xlsx", ExcelVersion.Version2013);
        }
    }
}

Imports Spire.Xls

Namespace MergeExcelFiles
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a string array from Excel file paths
            Dim inputFiles = New String() {"April.xlsx", "May.xlsx", "June.xlsx"}

            'Initialize a new Workbook object
            Dim newWorkbook As Workbook = New Workbook()
            'Clear the default worksheets
            newWorkbook.Worksheets.Clear()

            'Initialize another temporary Workbook object
            Dim tempWorkbook As Workbook = New Workbook()

            'Loop through the string array
            For Each file In inputFiles
                'Load the current workbook
                tempWorkbook.LoadFromFile(file)
                'Loop through the worksheets in the current workbook
                For Each sheet As Worksheet In tempWorkbook.Worksheets
                    'Copy each worksheet from the current workbook to the new workbook
                    newWorkbook.Worksheets.AddCopy(sheet, WorksheetCopyType.CopyAll)
                Next
            Next

            'Save the new workbook to file
            newWorkbook.SaveToFile("MergeWorkbooks.xlsx", ExcelVersion.Version2013)
        End Sub
    End Class
End Namespace

using Spire.Xls;

namespace MergeExcelWorksheets
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Workbook object
            Workbook workbook = new Workbook();
            //Load an Excel file
            workbook.LoadFromFile("Sample.xlsx");

            //Get the first worksheet
            Worksheet sheet1 = workbook.Worksheets[0];
            //Get the second worksheet
            Worksheet sheet2 = workbook.Worksheets[1];

            //Get the used range in the second worksheet
            CellRange sourceRange = sheet2.AllocatedRange;
            //Specify the destination range in the first worksheet
            CellRange destRange = sheet1.Range[sheet1.LastRow + 1, 1];

            //Copy the used range of the second worksheet to the destination range in the first worksheet
            sourceRange.Copy(destRange);

            //Remove the second worksheet
            sheet2.Remove();

            //Save the result file
            workbook.SaveToFile("MergeWorksheets.xlsx", ExcelVersion.Version2013);
        }
    }
}

Imports Spire.Xls

Namespace MergeExcelWorksheets
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Workbook object
            Dim workbook As Workbook = New Workbook()
            'Load an Excel file
            workbook.LoadFromFile("Sample.xlsx")

            'Get the first worksheet
            Dim sheet1 As Worksheet = workbook.Worksheets(0)
            'Get the second worksheet
            Dim sheet2 As Worksheet = workbook.Worksheets(1)

            'Get the used range in the second worksheet
            Dim sourceRange As CellRange = sheet2.AllocatedRange
            'Specify the destination range in the first worksheet
            Dim destRange As CellRange = sheet1.Range(sheet1.LastRow + 1, 1)

            'Copy the used range of the second worksheet to the destination range in the first worksheet
            sourceRange.Copy(destRange)

            'Remove the second worksheet
            sheet2.Remove()

            'Save the result file
            workbook.SaveToFile("MergeWorksheets.xlsx", ExcelVersion.Version2013)
        End Sub
    End Class
End Namespace