Vincent Snijders schrieb:
2011/5/9 Hans-Peter Diettrich <[email protected]>:
How would you tell the users, that a column width of -2 means auto-expand?
http://msdn.microsoft.com/en-us/library/bb761163%28v=vs.85%29.aspx
The value of LVSCW_AUTOSIZE_USEHEADER is -2.
Okay, that's a Windows specific convention. Unfortunately it is not
documented in a way that allows to implement it for other widgetsets.
E.g. what shall happen if a user tries to apply it to multiple columns?
What size should be assigned to the previous auto-expand column, when
another column becomes auto-expand?
A proper implementation IMO should implement the AutoSize (and other)
features in a widgetset independent way, e.g. in the TWSCustomListView
base class, for use in all widgetsets that don't support a feature
natively. This implementation defines what behaviour the user can expect
in every widgetset, as long as according documentation is missing.
In a portable environment there exist chances for incompatible
implementations of similar or essentially the same features, in
different widgetsets. The use of widgetset-specific features should be
allowed, of course, at the risk of the user; this means that the boolean
TListColumn.AutoSize property should be retyped, e.g. into an enum.
Otherwise it would be a good idea to add portable properties to the
ListView control itself, with an also portable implementation.
One such portable property could be what I tried to implement, an
automatic expansion of the rightmost column. A more flexible
implementation could specify a column that should be auto-expanded (kind
of alClient), with proper handling of column reordering. In any case the
implementation (calculation of concrete column widths) can reside
entirely in the control, without any special widgetset support.
DoDi
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