在运行时复制组件 [英] Duplicating components at Run-Time

问题描述

有没有一种简单的方式来复制父组件下的所有子组件，包括其已发布的属性？例如：

• TPanel
  
  
  
  
  • TLabel
  
  
  • TEdit
  
  
  • TListView
  
  
  • TSPecialClassX
  
  

当然是最重要的因素，它应该复制任何新的组件，我放在TPanel，而不修改代码在正常情况下。

我听说过RTTI，但从来没有使用过它。任何想法？

解决方案

阅读此页

< a href =http://www.blong.com/Conferences/BorConUK98/DelphiRTTI/CB140.htm =nofollow noreferrer> Delphi中的运行时类型信息 - 可以为您做任何事情吗？ / strong>

注意部分将属性从一个组件复制到另一个

其中有一个单元，RTTIUnit带有一个过程，似乎做了一部分你想要什么，但我不认为它将复制任何子组件与额外的代码。
（我认为它可以粘贴到这里...）

  （ObjFrom，ObjTo：TObject）; 
 var 
 PropInfos：PPropList; 
 PropInfo：PPropInfo; 
计数，循环：整数; 
 OrdVal：Longint; 
 StrVal：String; 
 FloatVal：Extended; 
 MethodVal：TMethod; 
 begin 
 // {通过所有已发布的字段和属性来源代码} 
 // {将它们复制到目标} 
 
 // {了解有多少属性我们将考虑} 
计数：= GetPropList（ObjFrom.ClassInfo，tkAny，nil）; 
 // {分配内存以保存其RTTI数据} 
 GetMem（PropInfos，Count * SizeOf（PPropInfo））; 
 try 
 // {获取我们新的缓冲区中的属性列表} 
 GetPropList（ObjFrom.ClassInfo，tkAny，PropInfos）; 
 // {循环所有选定的属性} 
为循环：= 0到计数 -  1 do 
 begin 
 PropInfo：= GetPropInfo（ObjTo.ClassInfo，PropInfos ^ [Loop ] ^。名称）; 
 // {检查属性的一般类型} 
 // {并以适当的方式读取/写入} 
 case PropInfos ^ [Loop] ^。PropType ^ .Kind of 
 tkInteger，tkChar，tkEnumeration，
 tkSet，tkClass {$ ifdef Win32}，tkWChar {$ endif}：
 begin 
 OrdVal：= GetOrdProp（ObjFrom，PropInfos ^ [Loop]） ; 
如果Assigned（PropInfo）然后
 SetOrdProp（ObjTo，PropInfo，OrdVal）; 
结束
 tkFloat：
 begin 
 FloatVal：= GetFloatProp（ObjFrom，PropInfos ^ [Loop]）; 
如果Assigned（PropInfo）然后
 SetFloatProp（ObjTo，PropInfo，FloatVal）; 
结束
 {$ ifndef DelphiLessThan3} 
 tkWString，
 {$ endif} 
 {$ ifdef Win32} 
 tkLString，
 {$ endif} 
 tkString：
 begin 
 {避免复制'名称' - 组件必须有唯一的名称} 
如果UpperCase（PropInfos ^ [Loop] ^。Name）='NAME'然后
继续; 
 StrVal：= GetStrProp（ObjFrom，PropInfos ^ [Loop]）; 
如果Assigned（PropInfo）然后
 SetStrProp（ObjTo，PropInfo，StrVal）; 
结束
 tkMethod：
 begin 
 MethodVal：= GetMethodProp（ObjFrom，PropInfos ^ [Loop]）; 
如果Assigned（PropInfo）然后
 SetMethodProp（ObjTo，PropInfo，MethodVal）; 
 end 
 end 
 end 
 finally 
 FreeMem（PropInfos，Count * SizeOf（PPropInfo））; 
结束
结束
  

Is there a simple way to duplicate all child components under parent component, including their published properties?

For example:

• TPanel
  • TLabel
  • TEdit
  • TListView
  • TSpecialClassX

Of course the most important factor, it should duplicate any new component which I drop on the TPanel without modifying the code under normal circumstances.

I've heard of the RTTI, but never used it actually. Any ideas?

解决方案

have a read of this page

Run-Time Type Information In Delphi - Can It Do Anything For You?

Noting the section Copying Properties From A Component To Another

which has a unit, RTTIUnit with a Procedure, which seems to do part of what you want but i don't think it will copy any child components with out extra code. (i think its ok to paste it here...)

procedure CopyObject(ObjFrom, ObjTo: TObject);    
  var
PropInfos: PPropList;
PropInfo: PPropInfo;
Count, Loop: Integer;
OrdVal: Longint;
StrVal: String;
FloatVal: Extended;  
MethodVal: TMethod;
begin
//{ Iterate thru all published fields and properties of source }
//{ copying them to target }

//{ Find out how many properties we'll be considering }
Count := GetPropList(ObjFrom.ClassInfo, tkAny, nil);
//{ Allocate memory to hold their RTTI data }
GetMem(PropInfos, Count * SizeOf(PPropInfo));
try
//{ Get hold of the property list in our new buffer }
GetPropList(ObjFrom.ClassInfo, tkAny, PropInfos);
//{ Loop through all the selected properties }
for Loop := 0 to Count - 1 do
begin
  PropInfo := GetPropInfo(ObjTo.ClassInfo, PropInfos^[Loop]^.Name);
 // { Check the general type of the property }
  //{ and read/write it in an appropriate way }
  case PropInfos^[Loop]^.PropType^.Kind of
    tkInteger, tkChar, tkEnumeration,
    tkSet, tkClass{$ifdef Win32}, tkWChar{$endif}:
    begin
      OrdVal := GetOrdProp(ObjFrom, PropInfos^[Loop]);
      if Assigned(PropInfo) then
        SetOrdProp(ObjTo, PropInfo, OrdVal);
    end;
    tkFloat:
    begin
      FloatVal := GetFloatProp(ObjFrom, PropInfos^[Loop]);
      if Assigned(PropInfo) then
        SetFloatProp(ObjTo, PropInfo, FloatVal);
    end;
    {$ifndef DelphiLessThan3}
    tkWString,
    {$endif}
    {$ifdef Win32}
    tkLString,
    {$endif}
    tkString:
    begin
      { Avoid copying 'Name' - components must have unique names }
      if UpperCase(PropInfos^[Loop]^.Name) = 'NAME' then
        Continue;
      StrVal := GetStrProp(ObjFrom, PropInfos^[Loop]);
      if Assigned(PropInfo) then
        SetStrProp(ObjTo, PropInfo, StrVal);
    end;
    tkMethod:
    begin
      MethodVal := GetMethodProp(ObjFrom, PropInfos^[Loop]);
      if Assigned(PropInfo) then
        SetMethodProp(ObjTo, PropInfo, MethodVal);
    end
  end
end
finally
  FreeMem(PropInfos, Count * SizeOf(PPropInfo));
end;
end;

这篇关于在运行时复制组件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！