PM> Install-Package Spire.XLS

using Spire.Xls;

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

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

            //Hide the 3rd and the 7th rows
            sheet.HideRow(3);
            sheet.HideRow(7);

            //Hide the 3rd and the 6th columns
            sheet.HideColumn(3);
            sheet.HideColumn(6);

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

Imports Spire.Xls

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

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

            'Hide the 3rd and the 7th rows
            sheet.HideRow(3)
            sheet.HideRow(7)

            'Hide the 3rd and the 6th columns
            sheet.HideColumn(3)
            sheet.HideColumn(6)

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

using Spire.Xls;

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

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

            //Show the 3rd and the 7th rows
            sheet.ShowRow(3);
            sheet.ShowRow(7);

            //Show the 3rd and the 6th columns
            sheet.ShowColumn(3);
            sheet.ShowColumn(6);

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

Imports Spire.Xls

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

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

            'Show the 3rd and the 7th rows
            sheet.ShowRow(3)
            sheet.ShowRow(7)

            'Show the 3ird and the 6th columns
            sheet.ShowColumn(3)
            sheet.ShowColumn(6)

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

using Spire.Xls;

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

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

            //Hide 3, 4 and 5 rows
            sheet.HideRows(3, 3);

            //Hide 5, 6 and 7 columns
            sheet.HideColumns(5, 3);

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

Imports Spire.Xls

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

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

            'Hide 3, 4 and 5 rows
            sheet.HideRows(3, 3)

            'Hide 5, 6 and 7 columns
            sheet.HideColumns(5, 3)

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

using Spire.Xls;

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

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

            //Iterate through the rows in the worksheet
            for (int i = 1; i <= sheet.LastRow; i++)
            {
                //Check if the current row is hidden
                if (sheet.GetRowIsHide(i))
                {
                    //Show the hidden row
                    sheet.ShowRow(i);
                }
            }

            //Iterate through the columns in the worksheet
            for (int j = 1; j <= sheet.LastRow; j++)
            {
                //Check if the current column is hidden
                if (sheet.GetColumnIsHide(j))
                {
                    //Show the hidden column
                    sheet.ShowColumn(j);
                }
            }

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

Imports Spire.Xls

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

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

            'Iterate through the rows in the worksheet
            For i As Integer = 1 To sheet.LastRow
                'Check if the current row is hidden
                If sheet.GetRowIsHide(i) Then
                    'Show the hidden row
                    sheet.ShowRow(i)
                End If
            Next

            'Iterate through the columns in the worksheet
            For j As Integer = 1 To sheet.LastRow
                'Check if the current column is hidden
                If sheet.GetColumnIsHide(j) Then
                    'Show the hidden column
                    sheet.ShowColumn(j)
                End If
            Next

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

PM> Install-Package Spire.Doc

using Spire.Doc;

namespace WordtoEPUB
{
    class Epub
    {
        static void Main(string[] args)
        {
            //Create a Document instance
            Document document = new Document();

            //Load a sample Word document
            document.LoadFromFile("demo.docx");

            //Convert the Word document to EPUB
            document.SaveToFile("ToEpub.epub", FileFormat.EPub);
        }
    }
}

Imports Spire.Doc

Namespace WordtoEPUB
    Class Epub
        Private Shared Sub Main(ByVal args As String())

            'Create a Document instance
            Dim document As Document = New Document()

            'Load a sample Word document
            document.LoadFromFile("demo.docx")

            'Convert the Word document to EPUB
            document.SaveToFile("ToEpub.epub", FileFormat.EPub)
        End Sub
    End Class
End Namespace 

using Spire.Doc;
using Spire.Doc.Fields;
using System.Drawing;

namespace ConvertWordToEpubWithCoverImage
{
    class Program
    {
        static void Main(string[] args)
        {

            //Create a Document instance
            Document doc = new Document();

            //Load a sample Word document
            doc.LoadFromFile("demo.docx");

            //Create a DocPicture instance
            DocPicture picture = new DocPicture(doc);

            //Load an image
            picture.LoadImage(Image.FromFile("CoverImage.png"));

            //Save the Word document to EPUB with cover image
            doc.SaveToEpub("ToEpubWithCoverImage.epub", picture);
        }
    }
}

Imports Spire.Doc
Imports Spire.Doc.Fields

Namespace ConvertWordToEpubWithCoverImage
    Class Program
        Private Shared Sub Main(ByVal args As String())

            'Create a Document instance
            Dim doc As Document = New Document()

            'Load a sample Word document
            doc.LoadFromFile("demo.docx")

            'Create a DocPicture instance
            Dim picture As DocPicture = New DocPicture(doc)

            'Load an image
            picture.LoadImage(Image.FromFile("CoverImage.png"))

            'Save the Word document to EPUB with cover image
            doc.SaveToEpub("ToEpubWithCoverImage.epub", picture)
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.XLS

using Spire.Xls;

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

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

            // Create a string array
            string[] values = new string[] { "Apple", "Banana", "Orange", "Strawberry", "Grape" };

            // Set data validation in cell A1 of the worksheet, restricting selectable values to those in the values array
            worksheet.Range["A1"].DataValidation.Values = values;

            // Save the Workbook object as an Excel file
            workbook.SaveToFile("DropdownListCreatedFromArray.xlsx", ExcelVersion.Version2016);

            // Dispose of the resources occupied by the Workbook object
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

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

            // Load workbook data from a file
            workbook.LoadFromFile("Sample1.xlsx");

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

            // Get the cell range from A3 to A8 in the worksheet
            CellRange dataRange = worksheet.Range["A3:A8"];

            // Set cell B1 as a dropdown with data range obtained earlier
            worksheet.Range["B1"].DataValidation.DataRange = dataRange;

            // Save the workbook to a new file
            workbook.SaveToFile("CreateDropdownInSameWorksheet.xlsx", ExcelVersion.Version2016);

            // Dispose of the workbook resources
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

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

            // Load the workbook from a file
            workbook.LoadFromFile("Sample2.xlsx");

            // Get the first worksheet
            Worksheet worksheet1 = workbook.Worksheets[0];

            // Get the second worksheet
            Worksheet worksheet2 = workbook.Worksheets[1];

            // Allow the use of 3D ranges in data validation
            worksheet1.ParentWorkbook.Allow3DRangesInDataValidation = true;

            // Define the data range
            CellRange dataRange = worksheet2.Range["A1:A6"];

            // Apply the data range to cell B1 in worksheet 1 as data validation
            worksheet1.Range["B1"].DataValidation.DataRange = dataRange;

            // Save the workbook to a file
            workbook.SaveToFile("Create the Dropdowns Across Different Worksheets.xlsx", ExcelVersion.Version2016);

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

using Spire.Xls;

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

            // Load the workbook from a file
            workbook.LoadFromFile("Sample3.xlsx");

            // Get the first worksheet
            Worksheet worksheet1 = workbook.Worksheets[0];

            // Get the second worksheet
            Worksheet worksheet2 = workbook.Worksheets[1];

            // Add named range objects and set reference ranges
            Spire.Xls.Core.INamedRange namedRange = workbook.NameRanges.Add(worksheet2.Range["A1"].Text);
            namedRange.RefersToRange = worksheet2.Range["B2:B6"];
            namedRange = workbook.NameRanges.Add(worksheet2.Range["A2"].Text.Replace(" ", "_"));
            namedRange.RefersToRange = worksheet2.Range["C2:C6"];
            namedRange = workbook.NameRanges.Add(worksheet2.Range["A3"].Text);
            namedRange.RefersToRange = worksheet2.Range["D2:D6"];
            namedRange = workbook.NameRanges.Add(worksheet2.Range["A4"].Text);
            namedRange.RefersToRange = worksheet2.Range["E2:E6"];
            namedRange = workbook.NameRanges.Add(worksheet2.Range["A5"].Text);
            namedRange.RefersToRange = worksheet2.Range["F2:F6"];

            // Allow 3D ranges in data validation
            worksheet1.ParentWorkbook.Allow3DRangesInDataValidation = true;

            // Set the data range for data validation
            worksheet1.Range["A2"].DataValidation.DataRange = worksheet2.Range["A1:A5"];
            worksheet1.Range["B2"].DataValidation.AllowType = CellDataType.User;

            // Set the formula
            worksheet1.Range["B2"].DataValidation.Formula1 = "=INDIRECT(SUBSTITUTE(A2,\" \",\"_\"))";

            // Save the workbook to a file
            workbook.SaveToFile("Linked Dropdowns in the Same Worksheet.xlsx", ExcelVersion.Version2016);

            // Dispose of the workbook resources
            workbook.Dispose();
        }
    }
}

using Spire.Xls;

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

                                     // Load the workbook from a file
                                     workbook.LoadFromFile("Sample4.xlsx");

                                     // Get the first worksheet
                                     Worksheet worksheet1 = workbook.Worksheets[0];

                                     // Get the second worksheet
                                     Worksheet worksheet2 = workbook.Worksheets[1];

                                     // Get the data worksheet
                                     Worksheet dataSheet = workbook.Worksheets[2];

                                     // Add a named range object and set the reference range
                                     Spire.Xls.Core.INamedRange namedRange = workbook.NameRanges.Add(dataSheet.Range["A2"].Text);
                                     namedRange.RefersToRange = dataSheet.Range["B2"];
                                     namedRange = workbook.NameRanges.Add(dataSheet.Range["A3"].Text);
                                     namedRange.RefersToRange = dataSheet.Range["B3"];
                                     namedRange = workbook.NameRanges.Add(dataSheet.Range["A4"].Text);
                                     namedRange.RefersToRange = dataSheet.Range["B4"];

                                     // Allow 3D ranges in data validation
                                     worksheet1.ParentWorkbook.Allow3DRangesInDataValidation = true;

                                     // Set the data range for data validation
                                     worksheet1.Range["B1"].DataValidation.DataRange = dataSheet.Range["A2:A4"];

                                     // Set the formula for cell B1 in the second worksheet
                                     worksheet2.Range["B1"].Formula = "=INDIRECT(" + worksheet1.Name + "!B1)";

                                     // Save the workbook to a file
                                     workbook.SaveToFile("Creating Linked Dropdowns Across Different Worksheets.xlsx", ExcelVersion.Version2016);

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