{$mode objfpc}{$H+} vs. VirtualTreeView

[asdf]

unit Unit1;

How to use {$mode objfpc}{$H+} and {$MODE Delphi}(for VirtualTreeView) in the same form ?

interface           

[Marc]

??? only the virtualtree unit needs the mode delphi, the other unit can use mode obfpc. there is no need to mix them.

[asdf]

But unfortunately, my project has only one form.
VirtualTreeView is in the same unit with many other controls of {$mode objfpc}{$H+}.

How can I solve this problem ?

[asdf]

Finally I just moved to use TreeListView instead.
It looks easier and I could finish learning/practicing the example within 1 hour.

[Marc]

But unfortunately, my project has only one form.
VirtualTreeView is in the same unit with many other controls of {$mode objfpc}{$H+}.

How can I solve this problem ?

Only the VirtualTreeView unit needs to be mode delphi (thats library code, you don't need to touch that), not the unit referring to it (thats your own, you can define any mode you want). I hope you dont decalre your control classes  in the same unit as where the virtual tree is defined.