Returns or sets a string that an application can use to execute a command. Read/write String.
Remarks
If the specified parameter is set for a built-in control, the application can modify its default behavior if it can parse and use the new value. If the parameter is set for custom controls, it can be used to send information to Visual Basic procedures, or it can be used to hold information about the control (similar to a second Tag property value).
Example
This example assigns a new parameter to a control and sets the focus to the new button.
Set myControl = CommandBars("Custom").Controls(4)
With myControl
.Copy , 1
.Parameter = "2"
.SetFocus
End With