Reputation: 1549

Can't get Microsoft.Office.Interop reference to work

I have a C# winforms app and I am simply trying to open an Excel sheet. When I try to add a reference to Microsoft.Office.Interop, the "Office" part is red and says "Can't resolve symbol 'Office'".

When I attempt to build, the error is:

The type or namespace name 'Office' does not exist in the namespace 'Microsoft' 
    (are you missing an assembly reference?)

I have Office 2012 installed, and I think I have the Primary Interop Assemblies installed... but I'm not positive.

I know that this should be so easy, but I've been looking around for an answer to this for almost an hour and just can't figure it out. Thanks in advance!

Upvotes: 38

Answers (7)

Prosterian

Reputation: 1

Just have the same issue and after some research i've realized that I'm trying to add reference in different project in solution (facepalm).

So be sure that you're trying to add reference in needed project. =)

Upvotes: 0

mattlongname

Reputation: 494

You need to add the library assembly reference to your project. They are referred to as "Primary Interop Assemblies".

(Assuming Visual Studio 2010)

Procedure

open the solution explorer window
expand your project folder accordion.
right click on the references element
select "add reference" from the dropdown
select the .NET tab and look for the object library called Microsoft.Office.Interop.Excel.
click ok

The object library should now appear in your references.

Upvotes: 36

Simon Hutchison

Reputation: 3035

Use NuGet Package Manager in VS2015

Right click references in your visual studio project
Select Manage NuGet Packages
Type microsoft.office in the search box
Select Microsoft.Office.Interop.Excel
Click Install
Rebuild your solution

Upvotes: 56

Behzad

Reputation: 2200

Easier way to add this package in VS 2015:

on the line code using the package press "Alt+Enter" then select "Find this namespace on nuget.org"

Install it and enjoy :)

Upvotes: 3

Mike Gledhill

Reputation: 29161

I had the same error this morning, with a Winforms app which had always built perfectly in the past. All that had changed was that our company had upgraded our laptops from Excel 2007 to Excel 2013.

After some investigating, I realised that the app was a .Net 3.5 app, and although the Solution Explorer suggested that all the refererences were fine..

...actually, they weren't. The tell-tail sign was that, when I tried to re-add the References in the app, they couldn't be found...

What I needed to do was:

update the app from .Net 3.5 to .Net 4.5
remove the Office-related References (the first 5 shown in my first screenshot above)
re-add the References (now shown as version 14 or 15)

I also had to change one line of code from: