Things need to be installed

Download from here

  • Open Office
  • Open Office SDK

The required files listed below:

  • cli_basetypes.dll
  • cli_cppuhelper.dll
  • cli_oootypes.dll
  • cli_ure.dll
  • cli_uretypes.dll

If you have installed Open Office SDK, you will get these files under sdk\cli on you installed SDK folder.

After give reference of above DLL files import following name space in .cs page.

using System;
using System.Diagnostics;
using System.IO;
using System.Threading;
using uno;
using uno.util;
using unoidl.com.sun.star.beans;
using unoidl.com.sun.star.frame;
using unoidl.com.sun.star.lang;

This is the method we used for convert any doc to pdf.

public void ConvertToPdf(string inputFile, string outputFile)
        {
            if (ConvertExtensionToFilterType(Path.GetExtension(inputFile)) == null)
                throw new InvalidProgramException("Unknown file type for OpenOffice. File = " + inputFile);

            StartOpenOffice();

            //Get a ComponentContext
            var xLocalContext =
                Bootstrap.bootstrap();
            //Get MultiServiceFactory
            var xRemoteFactory =
                (XMultiServiceFactory)
                xLocalContext.getServiceManager();
            //Get a CompontLoader
            var aLoader =
                (XComponentLoader)xRemoteFactory.createInstance("com.sun.star.frame.Desktop");
            //Load the sourcefile

            XComponent xComponent = null;
            try
            {
                xComponent = InitDocument(aLoader,
                                          PathConverter(inputFile), "_blank");
                //Wait for loading
                while (xComponent == null)
                {
                    Thread.Sleep(1000);
                }

                // save/export the document
                SaveDocument(xComponent, inputFile, PathConverter(outputFile));
            }
            finally
            {
                if (xComponent != null) xComponent.dispose();
            }
        }

private static void StartOpenOffice()
        {
            var ps = Process.GetProcessesByName("soffice.exe");
            if (ps.Length != 0)
                throw new InvalidProgramException("OpenOffice not found.  Is OpenOffice installed?");
            if (ps.Length > 0)
                return;
            var p = new Process
            {
                StartInfo =
                {
                    Arguments = "-headless -nofirststartwizard",
                    FileName = "soffice.exe",
                    CreateNoWindow = true
                }
            };
            var result = p.Start();

            if (result == false)
                throw new InvalidProgramException("OpenOffice failed to start.");
        }


        private static XComponent InitDocument(XComponentLoader aLoader, string file, string target)
        {
            var openProps = new PropertyValue[1];
            openProps[0] = new PropertyValue { Name = "Hidden", Value = new Any(true) };

            var xComponent = aLoader.loadComponentFromURL(
                file, target, 0,
                openProps);

            return xComponent;
        }

        private static void SaveDocument(XComponent xComponent, string sourceFile, string destinationFile)
        {
            var propertyValues = new PropertyValue[2];
            // Setting the flag for overwriting
            propertyValues[1] = new PropertyValue { Name = "Overwrite", Value = new Any(true) };
            //// Setting the filter name
            propertyValues[0] = new PropertyValue
            {
                Name = "FilterName",
                Value = new Any(ConvertExtensionToFilterType(Path.GetExtension(sourceFile)))
            };
            ((XStorable)xComponent).storeToURL(destinationFile, propertyValues);
        }

        private static string PathConverter(string file)
        {
            if (string.IsNullOrEmpty(file))
                throw new NullReferenceException("Null or empty path passed to OpenOffice");

            return String.Format("file:///{0}", file.Replace(@"\", "/"));
        }

        public static string ConvertExtensionToFilterType(string extension)
        {
            switch (extension)
            {
                case ".doc":
                case ".docx":
                case ".txt":
                case ".rtf":
                case ".html":
                case ".htm":
                case ".xml":
                case ".odt":
                case ".wps":
                case ".wpd":
                    return "writer_pdf_Export";
                case ".xls":
                case ".xlsb":
                case ".xlsx":
                case ".ods":
                    return "calc_pdf_Export";
                case ".ppt":
                case ".pptx":
                case ".odp":
                    return "impress_pdf_Export";

                default:
                    return null;
            }
        }