type
mypro = procedure (k: boolean) of object;
....
tmyclass = class
fpro: mypro;
...
procedure setpro(pro: mypro);
...
end;
procedure tmyclass.setpro(pro: mypro);
begin
//怎样判断pro的值是有效的呢??然后再赋值 fpro := pro;
end;
mypro = procedure (k: boolean) of object;
....
tmyclass = class
fpro: mypro;
...
procedure setpro(pro: mypro);
...
end;
procedure tmyclass.setpro(pro: mypro);
begin
//怎样判断pro的值是有效的呢??然后再赋值 fpro := pro;
end;
fpro := pro;或者if Assigned(pro) then
fpro := pro;
其有效性应该是这时已经判断过了的,
为什么还要判断呢?