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

Problem
Severity: Error
Code:CS0234
Description:The type or namespace name 'Office' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)
Project: ProjectName
File: C:\ProjectNAme\Class1.cs
Line: ...
               


Possible solutionts.

1. Menu "Build/Clean solution"
2. Chech the version of .Net Framework.
3. App/Add Referenece.../Select the Referenece.

Regards,