Inheritance for a group of controls

[Robert]

Hello all

I am trying to create several controls (textbox, richtextbox,
combobox, etc.) with added functionality (example: change background
color on enter, return to normal on exit). All this functionality is
common to all of the controls, and I'd like a way to create it just
once, rather than once for each control.

To clarify, I have one control declared as follows:

public class DataEntryTextbox : System.Windows.Forms.TextBox
{
...
}

and another declared as:

public class DataEntryRichTextbox :
System.Windows.Forms.RichTextBox
{
...
}

They have precisely the same overrides and added functionality. I'd
like to be able to control these from one place and not have to worry
about changing them every place that I implement them.

Any ideas?

Thanks in advance!
Robert