Programmatically open a word document in C#

I'm glad you were able to resolve the issue. For anyone who might encounter a similar problem in the future, I'd like to provide some additional context.

There are typically three common scenarios when opening Word documents:

Simply viewing the document - letting the user open and interact with it normally
Reading or modifying content programmatically - extracting or changing text, tables, etc. without showing the UI
Automating Word with full UI access - using Word's specific features like macros, formatting tools, or displaying the application to users

Since you're using Office Interop to open Word with visible UI, you've chosen option 3. However, there are some important considerations to keep in mind:

Every machine running your application must have Microsoft Office installed.
Microsoft explicitly doesn't support Office automation in server-side applications (ASP.NET, Windows Services, Azure Functions, etc.) due to security, stability, and performance concerns.
Without proper cleanup, Word processes can remain running in the background, causing memory leaks.

You could use this code snippet as a reference:

using Microsoft.Office.Interop.Word;
using System;
using System.Runtime.InteropServices;

Microsoft.Office.Interop.Word.Application wordApp = null;
Document doc = null;

try
{
    wordApp = new Microsoft.Office.Interop.Word.Application();
    object filePath = @"C:\Test\NewDocument.docx";
    object readOnly = false;
    object isVisible = true;
    object missing = Type.Missing;

    doc = wordApp.Documents.Open(ref filePath, ref missing, ref readOnly, 
                                  ref missing, ref missing, ref missing, 
                                  ref missing, ref missing, ref missing, 
                                  ref missing, ref isVisible);
    wordApp.Visible = true;

    // Your work with the document here
}
catch (Exception ex)
{
    MessageBox.Show($"Error opening document: {ex.Message}");
}
finally
{
    // Cleanup COM objects
    if (doc != null)
    {
        doc.Close(false);
        Marshal.ReleaseComObject(doc);
    }

    if (wordApp != null)
    {
        wordApp.Quit(false);
        Marshal.ReleaseComObject(wordApp);
    }

    GC.Collect();
    GC.WaitForPendingFinalizers();
}

Answer 2

To programmatically open a Word document in C#, you can use the Open method from the Documents collection in the Microsoft Office Interop library. Here's a basic example of how to do this:

using Microsoft.Office.Interop.Word;

// Create a new instance of Word application
Application wordApp = new Application();

// Open the document
Document doc = wordApp.Documents.Open(@"C:\Path\To\YourDocument.docx");

// Make the application visible (optional)
wordApp.Visible = true;

Make sure that the path to the document is correct and that the document exists at that location. The FileNotFoundException you are encountering suggests that the specified file path may be incorrect or that the Office Interop assemblies are not properly referenced in your project.

To resolve the assembly loading issue, ensure that you have the correct version of the Office Primary Interop Assemblies (PIAs) installed and referenced in your project. You can check the references in your project and ensure that they point to the correct version of the Office assemblies that match the version of Office installed on your machine.

If you're using Visual Studio, you can add the reference by:

Right-click on your project in the Solution Explorer.
Select "Add" > "Reference...".
In the Assemblies section, look for Microsoft.Office.Interop.Word and add it.

Also, ensure that your project is targeting the correct framework version that supports the Office Interop libraries.

If the problem persists, consider repairing your Office installation or reinstalling the necessary components.

Pieter Claassens 40 Reputation points

2026-01-15T12:24:36.9333333+00:00

Solved it with this code:

using Microsoft.Office.Interop.Word; using System; using System.Windows.Forms; namespace OpenWordPrettyPlease InitializeComponent(); private void button1_Click(object sender, EventArgs e) { Microsoft.Office.Interop.Word.Application wordApp = new Microsoft.Office.Interop.Word.Application(); object filePath = @"C:\Test\NewDocument.docx"; object readOnly = false; object isVisible = true; object missing = Type.Missing; // Open the Word document Document doc = wordApp.Documents.Open(ref filePath, ref missing, ref readOnly, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref missing, ref isVisible); wordApp.Visible = true; // Make Word visible } } }
Pieter Claassens 40 Reputation points

2026-01-15T12:26:05.5233333+00:00

Also added the following dependencies under the COM object: 1) Interop.Microsoft.Office.Core & Interop.Microsoft.Office.Interop.Word

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Programmatically open a word document in C#

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