Now i know what is cout for but what is std and what are these "::" for?
The :: operator is called the scope resolution operator. It's primarily there for accessing names declared in a namespace or class, and std is the C++ library's namespace. std::cout says to look for cout in the std namespace and fail if it's not there.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...