There are lots, but in my point of view it would be: button, checkbox, radio(select button), label, textbox, and combo box. But if you asked which ones were important, the answer would be all of the exsisting components!
That would depend on wich control you are talking about. But every control has to have the property: "(Name)", and most of them have "Disabled" and "visible".
In Visual Basic, a timer control is a control that calls it's associated "tick" method. This allows it to be used when an event has to happen when a certain amount of time has passed.
Visual Basic 2005, 2008, and 2010 use the following types: Boolean Byte Char Date Decimal Double Integer Long Object SByte Short Single String UInteger ULong User-Defined UShortBoolean holds values...