Hola Alvaro:

I usually do what Kevin suggested: use a class with static properties.

You can also use the localization features of .NET and store all your messages in resource files. I believe this is what Microsoft recommends, although, I must admit that I usually don't use resource files. Anyway, here is a good tutorial on how to use localization in .NET:
http://www.devhood.com/tutorials/tutorial_details.aspx?tutorial_id=211


Hector

>Sorry. English is not my first lenguage.
>
>In VFP exists .h files where is possible to define a constant and later any program doing (#include) can have access to these.
>
>Which is equivalent of this functionality in C # (if it exists)?
>
>Which is the best one practices to define constants (like for example all messages error, alert, etc) in a single part (it will be in a class)?
>
>Thanks for your comments.