Delphi: How to assign Click event to object's method?
i have a menu item, and i'm trying to assign its OnClick
event handler:
miFrobGizmo.OnClick := {something};
The OnClick
event handler property, like almost every other event handler, is defined as a TNotifyEvent
method type:
property OnClick: TNotifyEvent
where TNotifyEvent
is:
TNotifyEvent = procedure(Sender: TObject) of object;
i have an object, with a method matching the TNotifyEvent
signature:
TAnimal = class(TObject)
public
procedure Frob(Sender: TObject);
end;
So i think i should be able to take the method of the object and assign it to the clic开发者_JS百科k event handler:
var
Animal: TAnimal;
miFrobGizmo.OnClick := Animal.Frob;
Except i get the error:
[Error]File.pas(1234): Not enough actual parameters
Perhaps i'm having a brain fart, but i thought i should be able to do this.
A detail i failed to mention is that my object that has the matching method is having the method exposed though an interface:
IAnimal = interface
procedure Frob(Sender: TObject);
end;
TAnimal = class(TInterfacedObject, IAnimal)
public
procedure Frob(Sender: TObject);
end;
var
Animal: IAnimal;
miFrobGizmo.OnClick := Animal.Frob;
Follow-up question
If this won't work, what will?
You can't do that. It says "procedure of object", not "procedure of interface". It would let you do that if you were using an object directly, but since you're not, it doesn't consider that you're trying to assign the event handler and instead the parser tries to treat your code as a method call. Then it sees that you don't have any parameters for your method call, but the call requires one parameter so it gives up and gives you an error message.
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