Summary This article explores the interaction of COM components like Microsoft Word application with .Net Framework.

In this article, I am going to explore how we can interact with COM components like Microsoft Word application. I will explain this concept with a program which was written in both VB.Net and C#.Net. This program basically counts the number of characters in your document and displays all those characters in your console window. This gives you an idea on how COM components can interact with .Net framework.

First you need to create the Interop Assembly using Type Library Importer (Tlbimp.exe), which is a tool that converts COM type library coclasses and interfaces into metadata.

To execute this article on your machine, Microsoft Word should be installed. If installed, find the path of MsWord9.olb file. In Ideal cases the path will be C:\Program Files\Microsoft Office\Office. Then create the interop assembly from the type library, using the following command.

C:\pandu\asp\Word>Tlbimp C:\Program Files\Microsoft Office\Office\ MsWord9.olb /silent /out:Word.dll

Here the second argument /silent suppress the display of successful messages.

This command instruction creates a metadata, which is the Interop assembly.

Create a word document by saving it as WordTest.doc in C: drive. You can save this file anywhere but you need to give the path of this file in your code.

Then write the following programs, which uses the created Interop Assembly:

• wordConvert.cs

 Compile it as follows:

             C:\pandu\asp\Word>csc wordConvert.cs /r:Word.dll /r:System.dll

 Note that Word.dll and wordConvert.cs should be in the same folder.

Additional information

Code for wordConvert.cs ________________________________________________________ using System; using System.Diagnostics; using System.Runtime.InteropServices; using System.Reflection; using System.Collections; using System.Threading; using Word; namespace WordConversion { class WordConvertMain { static object missing = Missing.Value; static int Main() { WordConvertMain myWord = new WordConvertMain(); int return_Result = 0; // Create a word application object that we can read/write/manipulate Word.Application oWordApp = null; Word.Document oWordDoc=null; try { oWordApp = new Word.Application(); } catch(Exception e) { Console.WriteLine("Can't create a word application object " + e.ToString()); return_Result = 1; goto Exit; } string sMyDoc = "c:\\WordTest.doc"; object oDocFileName = sMyDoc; object oTrue = true; object oFasle = false; try { oWordDoc = oWordApp.Documents.Open(ref oDocFileName,ref missing,ref oTrue,ref missing,ref missing,ref missing,ref missing,ref missing,ref missing,ref missing,ref missing,ref oFasle); } catch(COMException e) { Console.WriteLine("COM Exception : " + e.ToString()); return_Result = 1; goto Exit; } catch(Exception e) { Console.WriteLine("Cannot open the document : " + e.ToString()); return_Result = 1; goto Exit; } //Hide the Word Document so that it will not appear oWordApp.Visible=false; //Display the count of Total number of Characters Console.WriteLine("Characters Count = " + oWordDoc.Characters.Count); int nParaCount; nParaCount = oWordDoc.Paragraphs.Count; Console.WriteLine("Paragraphs Count = " + nParaCount); int nCharCount; string sChar; char[~ sCharArray; Console.WriteLine("Printing Characters ..."); //Read the the characters of the Word Document and display them in the Console window. for (nCharCount=1; nCharCount <= oWordDoc.Characters.Count; nCharCount++) { sChar = oWordDoc.Characters.Item(nCharCount).Text; sCharArray = sChar.ToCharArray(); //Check Whether the character is New line character or not if (System.Text.Encoding.ASCII.GetBytes(sCharArray)[0~ == 13) { sChar = "New Line Character"; } //Check Whether the character is Horizontal Tab character or not if (System.Text.Encoding.ASCII.GetBytes(sCharArray)[0~ == 9) { sChar = "Horizontal Tab"; } Console.WriteLine(sChar); } // Close the opened Microsoft Word. This will kill the process of the Word oWordApp.Quit(ref missing, ref missing, ref missing); Exit: return return_Result; } } } Code for wordConvert.vb ____________________________________________________________ Imports System Imports System.Diagnostics Imports System.Runtime.InteropServices Imports System.Reflection Imports System.Collections Imports System.Threading Imports Microsoft.VisualBasic Imports Word Namespace WordConversion Class WordConvertMain Shared Sub Main() Dim myWord As WordConvertMain myWord = new WordConvertMain() Dim return_Result As Integer ' Create a word application object that we can read/write/manipulate Dim oWordApp As Word.Application oWordApp = Nothing Dim oWordDoc As Word.Document oWordDoc = Nothing Try oWordApp = new Word.Application() Catch e As Exception Console.WriteLine("Can't create a word application object " & e.ToString()) End Try Dim sMyDoc As String sMyDoc = "c:\\WordTest.doc" Dim oDocFileName As Object Dim oTrue As Object Dim oFalse As Object oDocFileName = sMyDoc oTrue = true oFalse = false Try oWordDoc = oWordApp.Documents.Open(oDocFileName, Missing.Value,true,Missing.Value,Missing.Value,Missing.Value,Missing.Value,Missing.Value,Missing.Value,Missing.Value,Missing.Value,false) Catch e As COMException Console.WriteLine("COM Exception : " & e.ToString()) Catch e As Exception Console.WriteLine("Cannot open the document : " & e.ToString()) End Try 'Hide the Word Document so that it will not appear oWordApp.Visible=false 'Display the count of Total number of Characters Console.WriteLine("Characters Count = " & oWordDoc.Characters.Count) Dim nParaCount As Integer nParaCount = oWordDoc.Paragraphs.Count Console.WriteLine("Paragraphs Count = " & nParaCount) Dim nCharCount As Integer Dim sChar As String Console.WriteLine("Printing Characters ...") 'Read the the characters of the Word Document and display them in the Console window. For nCharCount = 1 To oWordDoc.Characters.Count sChar = oWordDoc.Characters.Item(nCharCount).Text 'Check Whether the character is New line character or not If Asc(sChar) = 13 Then sChar = "New Line Character" End If 'Check Whether the character is Horizontal Tab character or not If Asc(sChar) = 9 Then sChar = "Horizontal Tab" End If Console.WriteLine(sChar) Next 'Close the opened Microsoft Word. This will kill the process of the Word oWordDoc = Nothing CType(oWordApp,Word._Application).Quit() oWordApp = Nothing End Sub End Class End Namespace