How to remove focus from currently focused component?
I have a DB component which DataLink.UpdateRecord is called when it receives CM_EXIT message. This message is sent when it loses focus. When I click post button, it doesn't lose focus and value is not written to datasource. How can I reach an effect of component los开发者_如何学Cing focus without switching it to other one?
You could use:
procedure TCustomForm.DefocusControl(Control: TWinControl; Removing: Boolean);
We accomplish this by setting the Self.ActiveControl := nil. That causes all of the exit events to fire. In our case we wanted to also re-focus back to the control after the save took place. That required a few extra checks to ensure we had a good control that could accept focus.
procedure TSaleEditor.SaveCurrentState();
var
SavedActiveControl: TWinControl;
AlternateSavedControl: TWinControl;
begin
// Force the current control to exit and save any state.
if Self.ActiveControl <> nil then
begin
SavedActiveControl := Self.ActiveControl;
// We may have an inplace grid editor as the current control. In that case we
// will not be able to reset it as the active control. This will cause the
// Scroll box to scroll to the active control, which will be the lowest tab order
// control. Our "real" controls have names, where the dynamic inplace editor do not
// find an Alternate control to set the focus by walking up the parent list until we
// find a named control.
AlternateSavedControl := SavedActiveControl;
while (AlternateSavedControl.Name = '') and (AlternateSavedControl.Parent <> nil) do
begin
AlternateSavedControl := AlternateSavedControl.Parent;
end;
Self.ActiveControl := nil;
// If the control is a radio button then do not re-set focus
// because if you are un-selecting the radio button this will automatically
// re-select it again
if (SavedActiveControl.CanFocus = true) and
((SavedActiveControl is TcxRadioButton) = false) then
begin
Self.ActiveControl := SavedActiveControl;
end
else if (AlternateSavedControl.CanFocus = true) and
((AlternateSavedControl is TcxRadioButton) = false) then
begin
Self.ActiveControl := AlternateSavedControl;
end;
end;
end;
Have a look at TCustomForm.FocusControl
. You can't make it lose focus without switching focus to something else, but you can switch and then immediately switch back, which would probably work.
There is a SetFocus function in windows unit. Try this:
Windows.SetFocus(0);
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