2011/6/1 Jorge Aldo G. de F. Junior <jagf...@gmail.com>: > I am having problems with virtual methods. > > I have two classes, the second one is a descendent of the first : > > 1st: > > TTreeNode = Class(TObject) > Public > Constructor Create(Const aOwner : TTreeNode); Virtual; > > 2nd : > TTreeNodeWithProperties = Class(TTreeNodeWithName) > Public > Constructor Create(Const aOwner : TTreeNodeWithProperties); > Override; >
TTreeNode is a different type than TTreeNodeWithProperties. I think you should override the constructor with base type as param: Constructor Create(Const aOwner : TTreeNode); Override; At runtime check with: if not (aOwner is TTreeNodeWithProperties) then raise exception.... inherited Create(aOwner); ... If you define a different constructor with the derived type as param : Constructor Create(Const aOwner : TTreeNodeWithProperties); Overload; then if you're passing TTreeNode objects to TTreeNodeWithProperties constructor it will only call the base constructor. -- cobines _______________________________________________ fpc-pascal maillist - fpc-pascal@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-pascal
