I was reading [this question](https://stackoverflow.com/q/2903430/1882077) when I noticed a curious comment underneath:

> 
> not sure what the question is: you can use VB.NET and C# projects in one solution (though I wouldn't recommend doing so).
> 
> 
> 

I do this quite a bit, as we have legacy VB.Net code, and new code is written in C#. Is this really not recommended? Why not?
['https://Stackoverflow.com/questions/15706564', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/969613/']
The only reason that it wouldn't be recommended is consistency. Most developers prefer to deal with a single language when working on an application. Having a single language also means that your developers only need to know a single language rather than knowing both VB.NET and C# (even though the two are extremely similar).

If you need to mix legacy VB.NET and C#, there's no reason not to.
Its just a matter of person choice. if you are comfortable with both the languages, You surely can use them in same solution.

Using a single language in a solution seems easily maintainable. hence it is preferred.