This post is about when to fire BeforeDrawRow event and when not. In my opinion (and maybe others as well) the BeforeDrawRow event is overdoing it's job. There are cases when no event is required because nothing has to be redrawn (in my opinion) but maybe there are members who need the event anyway. Here's a list of cases in which I don't think the event has to be fired.

 

Note:  Mark asked me to produce this list because of some problems we encountered in Jason's Markup Demo ( https://forum.codejock.com/forum_posts.asp?TID=14983 - https://forum.codejock.com/forum_posts.asp?TID=14983 )

Please, if you can think of other cases, don't hesitate to reply.

 

Thanks a lot

 

 

 

every event change the focus and so the layout of cells.

Please don't change this behavior.

 

Hi Baldur,

 

I'm glad someone joined the discussion  

 

My question to you: why should fire BeforeDrawRow event on a mouseclick (or any of the other cases in my list) The RC looks exactly the same as before I clicked in RC area. So in these cases I don't want that event to fore. Just for fun, add some counter in BeforeDrawRow event in Jason Demo with Markup widgets and see how many times the BeforeDrawRow fires. It's consumes a lot of (sometimes) processor time and in some cases "forgets" the (like in Jason's Demo) mouseclick.

 

Just give me a reason why the event should still fire not just: "every event change the focus and so the layout of cells.

Please don't change this behavior"     

 

Thank you for reply and I hope many others will join in this discussion

 

 

 

i have tested this "counter" long time ago, maybe with Version 9 and found also that the event somtimes is send oftener as needed.

But the main problem in this case is windows and "InvalidateRect" to reduce this events.

 

I think, that the Report don't store the Metrics-Property in the Cells-Properties so in case of repaint, he must ask for.

On the other hand, you can decide by yourself with SetCustomDraw at runtime when events should occur or not.

 

So you can decide in case of FocusChanging to turn the xtpCustomBeforeDrawRow on or off to reduce the events.

But in case of scrolling, sorting, grouping, the events are gone (no FocusChanging).

 

On the other hand, most properties of metrics can be set for each individual items so perhaps you don't need this event.

 

What i found is, that this event is fired for each column in the grid.

It can be automaticly reduced to only the visible columns !

 

Regards

Baldur

 

It seems that I'm the only in here who has an opinion (except for Baldur of course) so I will leave it as is and will create my own "Update event" at least for Markup.

 

Thank you