How to check or uncheck a TCheckBox without causing an OnClick event

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How to check or uncheck a TCheckBox without causing an OnClick event

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Question:

My application needs to update a few checkboxes and other controls but no events shall be fired by these changes. How can I prevent those OnClick() and other events?

Answer:

Before you update the control(s), you need to ..

assign NIL to the event handler property for each control

then update the control

reassign the correct event handler - as shown in the code below.

If several controls share one event handler, it would be more elegant to have a boolean flag which you temporarily set to false and the event handler(s) would check this flag before they do anything.

procedure SetCheckBox(chk: TCheckBox; b: boolean);
var
  NE: TNotifyEvent;
begin { SetCheckBox }
  with chk do 
  begin 
    NE := OnClick;
    OnClick := nil; 
    Checked := b; 
    OnClick := NE
  end; { with chk } 
end; { SetCheckBox }

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Comments:

2008-02-14, 09:21:36

anonymous from Betzdorf, Luxembourg

yuyuy

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