PM> Install-Package Spire.PDF

using Spire.Pdf;
using Spire.Pdf.Graphics;
using System.Drawing;

namespace DeleteBlankPage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Apply license by license key
            Spire.Pdf.License.LicenseProvider.SetLicenseKey("your license key");

            //Create a PdfDocument instance
            PdfDocument document = new PdfDocument();

            //Load a sample PDF document
            document.LoadFromFile("input.pdf");

            //Loop through all pages in the PDF
            for (int i = document.Pages.Count - 1; i >= 0; i--)
            {
                //Detect if a page is blank
                if (document.Pages[i].IsBlank())
                {
                    //Remove the absolutely blank page
                    document.Pages.RemoveAt(i);
                }
                else
                {
                    //Save PDF page as image
                    Image image = document.SaveAsImage(i, PdfImageType.Bitmap);

                    //Detect if the converted image is blank
                    if (IsImageBlank(image))
                    {
                        //Remove the page
                        document.Pages.RemoveAt(i);
                    }
                }
            }

            //Save the result document
            document.SaveToFile("RemoveBlankPage.pdf", FileFormat.PDF);
        }

        //Detect if an image is blank
        public static bool IsImageBlank(Image image)
        {
            Bitmap bitmap = new Bitmap(image);
            for (int i = 0; i < bitmap.Width; i++)
            {
                for (int j = 0; j < bitmap.Height; j++)
                {
                    Color pixel = bitmap.GetPixel(i, j);
                    if (pixel.R < 240 || pixel.G < 240 || pixel.B < 240)
                    {
                        return false;
                    }
                }
            }
            return true;
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Graphics

Namespace DeleteBlankPage
    Class Program
        Private Shared Sub Main(ByVal args() As String)
            'Apply license by license key
            Spire.License.LicenseProvider.SetLicenseKey("your license key")

            'Create a PdfDocument instance
            Dim document As PdfDocument = New PdfDocument

            'Load a sample PDF document
            document.LoadFromFile("input.pdf")

            'Loop through all pages in the PDF
            Dim i As Integer = (document.Pages.Count - 1)
            Do While (i >= 0)

                'Detect if a page is blank
                If document.Pages(i).IsBlank Then

                    'Remove the absolutely blank page
                    document.Pages.RemoveAt(i)
                Else

                    'Save PDF page as image
                    Dim image As Image = document.SaveAsImage(i, PdfImageType.Bitmap)

                    'Detect if the converted image is blank
                    If Program.IsImageBlank(image) Then

                        'Remove the page
                        document.Pages.RemoveAt(i)
                    End If

                End If

                i = (i - 1)
            Loop

            'Save the result document
            document.SaveToFile("RemoveBlankPage.pdf", FileFormat.PDF)
        End Sub

        'Detect if an image is blank
        Public Shared Function IsImageBlank(ByVal image As Image) As Boolean
            Dim bitmap As Bitmap = New Bitmap(image)
            Dim i As Integer = 0
            Do While (i < bitmap.Width)
                Dim j As Integer = 0
                Do While (j < bitmap.Height)
                    Dim pixel As Color = bitmap.GetPixel(i, j)
                    If ((pixel.R < 240) _
                                OrElse ((pixel.G < 240) _
                                OrElse (pixel.B < 240))) Then
                        Return False
                    End If

                    j = (j + 1)
                Loop

                i = (i + 1)
            Loop

            Return True
        End Function
    End Class
End Namespace

PM> Install-Package Spire.Presentation

using Spire.Presentation;
using System.Drawing;

namespace ConvertPowerPointToJpgOrPngImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"Sample.pptx");

            int i = 0;
            //Iterate through all slides in the PowerPoint document
            foreach(ISlide slide in presentation.Slides)
            {
                //Save each slide as PNG image
                Image image = slide.SaveAsImage();
                string fileName = string.Format("ToImage-img-{0}.png", i);
                image.Save(fileName, System.Drawing.Imaging.ImageFormat.Png);
                i++;
            }
        }
    }
}

Imports Spire.Presentation

Namespace ConvertPowerPointToJpgOrPngImage
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("Sample.pptx")

            Dim i = 0
            'Iterate through all slides in the PowerPoint document
            For Each slide As ISlide In presentation.Slides
                'Save each slide as PNG image
                Dim image As Image = slide.SaveAsImage()
                Dim fileName = String.Format("ToImage-img-{0}.png", i)
                image.Save(fileName, Drawing.Imaging.ImageFormat.Png)
                i += 1
            Next
        End Sub
    End Class
End Namespace

using Spire.Presentation;

namespace ConvertPowerPointToTiffImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"Sample.pptx");

            //Convert the PowerPoint document to TIFF image
            presentation.SaveToFile("toTIFF.tiff", FileFormat.Tiff);
        }
    }
}

Imports Spire.Presentation

Namespace ConvertPowerPointToTiffImage
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("Sample.pptx")

            'Convert the PowerPoint document to TIFF image
            presentation.SaveToFile("toTIFF.tiff", FileFormat.Tiff)
        End Sub
    End Class
End Namespace

using Spire.Presentation;

namespace ConvertPowerPointToEmfImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"Sample.pptx");

            int i = 0;
            //Iterate through all slides in the PowerPoint document
            foreach (ISlide slide in presentation.Slides)
            {
                string fileName = string.Format("ToEmf-{0}.emf", i);
                //Save each slide to EMF image
                slide.SaveAsEMF(fileName);
                //Save each slide to EMF image with specified width and height
                //slide.SaveAsEMF(fileName, 1075, 710);
                i++;
            }
        }
    }
}

Imports Spire.Presentation

Namespace ConvertPowerPointToEmfImage
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("Sample.pptx")

            Dim i = 0
            'Iterate through all slides in the PowerPoint document
            For Each slide As ISlide In presentation.Slides
                Dim fileName = String.Format("ToEmf-{0}.emf", i)
                'Save each slide to EMF image
                slide.SaveAsEMF(fileName)
                'Save each slide to EMF image with specified width and height
                'slide.SaveAsEMF(fileName, 1075, 710);
                i += 1
            Next
        End Sub
    End Class
End Namespace

using Spire.Presentation;
using System.Collections.Generic;
using System.IO;

namespace ConvertPowerPointToSvgImage
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation presentation = new Presentation();
            //Load a PowerPoint document
            presentation.LoadFromFile(@"Sample.pptx");

            //Convert the PowerPoint document to SVG and save the results into a queue of byte arrays
            Queue<byte[]> svgBytes = presentation.SaveToSVG();
            int count = svgBytes.Count;
            //Iterate through the byte arrays in the queue
            for (int i = 0; i < count; i++)
            {
                //Remove and return the byte array at the beginning of the queue
                byte[] bt = svgBytes.Dequeue();
                //Specify the output file name
                string fileName = string.Format("ToSVG-{0}.svg", i);
                //Create a FileStream instance
                FileStream fs = new FileStream(fileName, FileMode.Create);
                //Save the byte array to a SVG file
                fs.Write(bt, 0, bt.Length);
            }
        }
    }
}

Imports Spire.Presentation
Imports System.Collections.Generic
Imports System.IO

Namespace ConvertPowerPointToSvgImage
    Friend Class Program
        Private Shared Sub Main(ByVal args As String())
            'Create a Presentation instance
            Dim presentation As Presentation = New Presentation()
            'Load a PowerPoint document
            presentation.LoadFromFile("Sample.pptx")

            'Convert the PowerPoint document to SVG and save the results into a queue of byte arrays
            Dim svgBytes As Queue(Of Byte()) = presentation.SaveToSVG()
            Dim count = svgBytes.Count
            'Iterate through the byte arrays in the queue
            For i = 0 To count - 1
                'Remove and return the byte array at the beginning of the queue
                Dim bt As Byte() = svgBytes.Dequeue()
                'Specify the output file name
                Dim fileName = String.Format("ToSVG-{0}.svg", i)
                'Create a FileStream instance
                Dim fs As FileStream = New FileStream(fileName, FileMode.Create)
                'Save the byte array to a SVG file
                fs.Write(bt, 0, bt.Length)
            Next
        End Sub
    End Class
End Namespace

PM> Install-Package Spire.Doc

using Spire.Doc;
using Spire.Doc.Documents;
using Spire.Doc.Fields;

namespace ExtractTextFromTextbox
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a Document object
            Document document = new Document();

            // Load a Word file
            document.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.docx");

            // Get a specific textbox
            TextBox textBox = document.TextBoxes[0];

            // Create a StreamWriter to write extracted text to a txt file
            using (StreamWriter sw = File.CreateText("result.txt"))
            {
                // Iterate though child objects of the textbox
                foreach (DocumentObject objt in textBox.ChildObjects)
                {
                    // Determine if the child object is a paragraph
                    if (objt.DocumentObjectType == DocumentObjectType.Paragraph)
                    {
                        // Write paragraph text to the txt file
                        sw.Write((objt as Paragraph).Text);
                    }

                    // Determine if the child object is a table
                    if (objt.DocumentObjectType == DocumentObjectType.Table)
                    {
                        // Extract text from table to the txt file
                        ExtractTextFromTable(objt as Table, sw);
                    }
                }

            }
 
        }

        // Extract text from a table
        static void ExtractTextFromTable(Table table, StreamWriter sw)
        {
            for (int i = 0; i < table.Rows.Count; i++)
            {
                TableRow row = table.Rows[i];
                for (int j = 0; j < row.Cells.Count; j++)
                {
                    TableCell cell = row.Cells[j];
                    foreach (Paragraph paragraph in cell.Paragraphs)
                    {
                        sw.Write(paragraph.Text);
                    }
                }
            }
        }
    }
}

using Spire.Doc;
using Spire.Doc.Documents;
using Spire.Doc.Fields;

namespace UpdateTextbox
{
    class Program
    {
        static void Main(string[] args)
        {
            // Create a Document object
            Document document = new Document();

            // Load a Word file
            document.LoadFromFile("C:\\Users\\Administrator\\Desktop\\Input.docx");

            // Get a specific textbox
            TextBox textBox = document.TextBoxes[0];

            // Remove child objects of the textbox
            textBox.ChildObjects.Clear();

            // Add a new paragraph to the textbox
            Paragraph paragraph = textBox.Body.AddParagraph();

            // Set line spacing
            paragraph.Format.LineSpacing = 15f;

            // Add text to the paragraph
            TextRange textRange = paragraph.AppendText("The text in this textbox has been updated.");

            // Set font size
            textRange.CharacterFormat.FontSize = 15f;

            // Save the document to a different Word file
            document.SaveToFile("UpdateTextbox.docx", FileFormat.Docx2019);

            // Dispose resources
            document.Dispose();
        }

    }

}