ElXTree.HeaderSections.BeginUpdate doesn't prevent the tree from updating on the screen.

Raymond Kennington

Delphi XE3, LMD 2019.1.0.0.

When printing an ElXTree, I change the fields being printed according to user preferences, and then change them back again after printing.

Using ElXTree.Items.BeginUpdate(), the XTree is visually frozen from changes and EndUpdate(). 

Really nice. I speeds up the process considerably.

I expected the same to occur with ElXTree.HeaderSections.BeginUpdate, but it doesn't prevent the tree from updating on the screen.

The user would see the headings change without the data changing.

Is there a way of making this work?

If not, please make it work before June. 

If you can't do that, please tell me how to change the source so that it does this.

Eugene Balabuev (LMD)

Hi,

Confirmed. I can try to fix it, since, header flickering does not really happen when using TElHeader control itself, which is used internally inside XTree). 

However, BeginUpdate/EndUpdate do not guarantee flicker free behavior. It just minimize flickering, since the control will be re-calculated and redrawn after EndUpdate anyway. 

Moreover, the methods are not designed to perform printing between of them. Printing MAY work, but this is not guaranteed, because some internal data can may be re-calculated only while control's drawing.

But, as mentioned, I'll try to fix flickering.

Eugene Balabuev (LMD)

Fixed. But, keep in mind previously mentiond limitations.