private void button1_Click(object sender, EventArgs e)
        {
            //connect database
            OleDbConnection connection = new OleDbConnection();
            connection.ConnectionString @"Provider=""Microsoft.Jet.OLEDB.4.0"";Data Source=""demo.mdb"";User Id=;Password="
            OleDbCommand command = new OleDbCommand();
            command.CommandText = "select * from parts";
            DataSet dataSet = new System.Data.DataSet();
            OleDbDataAdapter dataAdapter = new OleDbDataAdapter(command.CommandText,connection);
            dataAdapter.Fill(dataSet);
            DataTable t = dataSet.Tables[0];
            //export datatable to excel
            Workbook book = new Workbook();
            Worksheet sheet = book.Worksheets[0];
            sheet.InsertDataTable(t, true, 1, 1);
            book.SaveToFile("insertTableToExcel.xls",ExcelVersion.Version97to2003);
            System.Diagnostics.Process.Start("insertTableToExcel.xls");
        }

Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        //connect database
        Dim connection As OleDbConnection = New OleDbConnection
        connection.ConnectionString = “Provider=””Microsoft.Jet.OLEDB.4.0””;
Data Source=""demo.mdb""; User Id=;Password="
        Dim command As OleDbCommand = New OleDbCommand
        command.CommandText = "select * from parts"
        Dim dataSet As DataSet = New System.Data.DataSet
        Dim dataAdapter As OleDbDataAdapter = New OleDbDataAdapter(command.CommandText, connection)
        dataAdapter.Fill(dataSet)
        Dim t As DataTable = dataSet.Tables(0)
        //export datatable to excel
        Dim book As Workbook = New Workbook
        Dim sheet As Worksheet = book.Worksheets(0)
        sheet.InsertDataTable(t, True, 1, 1)
        book.SaveToFile("insertTableToExcel.xls",ExcelVersion.Version97to2003)
        System.Diagnostics.Process.Start("insertTableToExcel.xls")
    End Sub
End Class

using Spire.Pdf;
using Spire.Pdf.Attachments;
using System;
using System.Windows.Forms;


namespace RemoveAttachments
{
    class Program
    {
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog dialog = new OpenFileDialog();
            dialog.Filter = "PDF document(*.pdf)|*.pdf";
            DialogResult result = dialog.ShowDialog();
            if (result == DialogResult.OK)
            {
                PdfDocument doc = new PdfDocument();
                doc.LoadFromFile(dialog.FileName);
                PdfAttachmentCollection attachments = doc.Attachments;
                PdfAttachment attachment = null;
                if (doc.Attachments.Count > 0)
                {
                    foreach (PdfAttachment oneAttachment in doc.Attachments)
                    {
                        string filename = oneAttachment.FileName;
                        if (filename == "excel.xlsx")
                        {
                            attachment = oneAttachment;
                            break;
                        }
                    }
                }
                if (attachment != null)
                {
                    doc.Attachments.Remove(attachment);
                }
                doc.SaveToFile("test.pdf");
                System.Diagnostics.Process.Start("test.pdf");
            }
        }
    }
}

Imports Spire.Pdf
Imports Spire.Pdf.Attachments
Imports System.Windows.Forms


Namespace RemoveAttachments
	Class Program
		Private Sub button1_Click(sender As Object, e As EventArgs)
			Dim dialog As New OpenFileDialog()
			dialog.Filter = "PDF document(*.pdf)|*.pdf"
			Dim result As DialogResult = dialog.ShowDialog()
			If result = DialogResult.OK Then
				Dim doc As New PdfDocument()
				doc.LoadFromFile(dialog.FileName)
				Dim attachments As PdfAttachmentCollection = doc.Attachments
				Dim attachment As PdfAttachment = Nothing
				If doc.Attachments.Count > 0 Then
					For Each oneAttachment As PdfAttachment In doc.Attachments
						Dim filename As String = oneAttachment.FileName
						If filename = "excel.xlsx" Then
							attachment = oneAttachment
							Exit For
						End If
					Next
				End If
				If attachment IsNot Nothing Then
					doc.Attachments.Remove(attachment)
				End If
				doc.SaveToFile("test.pdf")
				System.Diagnostics.Process.Start("test.pdf")
			End If
		End Sub
	End Class
End Namespace