>In Vfox i use _screen to hang properties or objects that can be accessed by forms , i m trying to do the same in .Net using a mdiform in which i create some public properties but i can't find the way for those propeties in MdiForm may be accessed by child forms.

Juan,
In VFP too normal way is to use a custom object (oMyApp) to store such info. You can do the similar in .Net. Check Thread #1040828 (it's C# but gives the idea).
Cetin