The type or namespace name ‘Office’ does not exist in the namespace ‘Microsoft’ – How to Resolve

Hi friends, in this article, we will be discussing about, how you can resolve the following error you might get in your Visual Studio project: CS0234 The type or namespace name ‘Office’ does not exist in the namespace ‘Microsoft’ (are you missing an assembly reference?)

 

Why I Received this Error Message?

The reason you received the above error message, as its description implies, is because you are missing an assembly reference and more specifically, most probably, you are missing a Microsoft.Office.Interop… assembly.

For example, you might be missing the “Microsoft.Office.Interop.Excel” assembly, or “Microsoft.Office.Interop.Word”, etc.

 

How to Resolve the Microsoft.Office.Interop… Assembly Error

Normally, in order to resolve the issue, you would need within Visual Studio, to right-click on the project in the Solution Explorer, and select to add the missing “Microsoft.Office.Interop…” assembly reference (References — Add Reference).

However, most probably, you will not be able to find the specific Microsoft.Office.Interop… assembly in the list of assemblies (just like the below example).

 

So, how do we resolve the issue?

 

The easiest way to resolve the above issue, is to use the NuGet Package Manager utility under “Tools” within Visual Studio.

To this end, after opening your project in Visual Studio, you can navigate to “Tools”, then “NuGet Package Manager” and finally, select the “Manage NuGet Packages for Solution…”

 

From the specific NuGet Package Manager dialog, you navigate to the “Browse” tab, and from there, you search for the “Microsoft.Office.Interop”  assembly you are looking for.

In our example, we are looking for “Microsoft.Office.Interop.Excel”.

So, as you can see from the below screenshot, we have found the assembly. As soon as we click on the assembly, we see in a small dialog to the right, whether is included in our project or not (obviously it is not installed).

To this end, we select the project for which we want to install the assembly, we select the version of the assembly we want to install and we click on the “Install” button:

 

Finally, we confirm about the changes to our project and if all good, we click on “OK”:

 

Right after that, the missing assembly will be added to our project.

 

Hope this helps!

 

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