使用他的ClassType转换TObject？ [英] cast TObject using his ClassType?

问题描述

我如何使我的代码工作？ :)我试图制定这个问题，但经过几次失败的尝试，我想你们会发现问题更快地看代码，而不是阅读我的解释。谢谢。

how can i make my code to work ? :) i`ve tried to formulate this question but after several failed attempts i think you guys will spot the problem faster looking at the code than reading my 'explanations'. thank you.

setCtrlState([ memo1, edit1, button1], False);

_

procedure setCtrlState(objs: array of TObject; bState: boolean = True);
var
  obj: TObject;
  ct: TClass;
begin
  for obj in objs do
  begin
    ct := obj.ClassType;


    if (ct = TMemo) or (ct = TEdit) then
      ct( obj ).ReadOnly := not bState;        // error here :(

    if ct = TButton then
      ct( obj ).Enabled:= bState;        // and here :(

  end;
end;

推荐答案

使用起来会更容易RTTI而不是显式转换，即：

It would be easier to use RTTI instead of explicit casting, ie:

uses
  TypInfo;

setCtrlState([ memo1, edit1, button1], False);

procedure setCtrlState(objs: array of TObject; bState: boolean = True);
var
  obj: TObject;
  PropInfo: PPropInfo;
begin
  for obj in objs do
  begin
    PropInfo := GetPropInfo(obj, 'ReadOnly');
    if PropInfo <> nil then SetOrdProp(obj, PropInfo, not bState);

    PropInfo := GetPropInfo(obj, 'Enabled');
    if PropInfo <> nil then SetOrdProp(obj, PropInfo, bState);
  end;
end;

这篇关于使用他的ClassType转换TObject？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！