OnUpdateUI
OnUpdateUI is called when the command state is changed and it is
time to update toolbar buttons, menus etc.
I always place the UI-updating stuff in OnCommandStateChanged
and have not been able to find situations where one could benefit
from using OnUpdateUI instead. OnUpdateUI seems to be called more
often then OnCommandStateChanged.
The following sample uses OnUpdateUI to make sure that menu-item
'Copy' (CopyMenu) is enabled only when text has been selected.
function TForm1.EmbeddedWB1UpdateUI:
HRESULT;
begin
CopyMenu.Enabled:=(Embeddedwb1.QueryStatusWB(OLECMDID_COPY)=OLECMDF_ENABLED
or OLECMDF_SUPPORTED);
end;
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