资料来源 : pyDict
拖放
资料来源 : Free On-Line Dictionary of Computing
drag and drop
A common method for manipulating files (and sometimes text)
under a {graphical user interface} or {WIMP} environment. The
user moves the pointer over an icon representing a file and
presses a mouse button. He holds the button down while moving
the pointer (dragging the file) to another place, usually a
directory viewer or an icon for some {application program},
and then releases the button (dropping the file). The meaning
of this action can often be modified by holding certain keys
on the keyboard at the same time.
Some systems also use this technique for objects other than
files, e.g. portions of text in a {word processor}.
The biggest problem with drag and drop is does it mean "copy"
or "move"? The answer to this question is not intuitively
evident, and there is no consensus for which is the right
answer. The same vendor even makes it move in some cases and
copy in others. Not being sure whether an operation is copy
or move will cause you to check very often, perhaps every time
if you need to be certain. Mistakes can be costly. People
make mistakes all the time with drag and drop. {Human
computer interaction} studies show a higher failure rate for
such operations, but also a higher "forgiveness rate" (users
think "silly me") than failures with commands (users think
"stupid machine"). Overall, drag and drop took some 40 times
longer to do than single-key commands.
[Erik Naggum ]