Как присвоить все значения полей одного класса, другому такому же классу?

How can I assign all property values (or if it's not possible only published property values, or some of them) of one class (TComponent) to another instance of the same class? What I want to do is:

Is there a better and shorter way to do this? I tried this: MyComponent1 := MyComponent2; But it doesn't work. Why not? Can I point to the second component ?

MyComponent2 and MyComponent1 are pointers to your components, and this kind of assigment leads to MyComponent1 pointing to MyComponent2. But it will not copy its property values.

A better way is to override the assign method of your control, do all property assignment there and call it when you need to copy component attributes. Here's example:

Code:

procedure TMyComponent.Assign(Source: TPersistent);

begin

if Source is TMyComponent then

begin

property1 := TMyComponent(Source).property1;

{ ... }

end

else

inherited Assign(Source);

end;

Code:

procedure EqualClassProperties(AClass1, AClass2: TObject);

var

PropList: PPropList;

ClassTypeInfo: PTypeInfo;

ClassTypeData: PTypeData;

i: integer;

NumProps: Integer;

APersistent : TPersistent;

begin

if AClass1.ClassInfo <> AClass2.ClassInfo then

exit;

ClassTypeInfo := AClass1.ClassInfo;

ClassTypeData := GetTypeData(ClassTypeInfo);

if ClassTypeData.PropCount <> 0 then

begin

GetMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);

try

GetPropInfos(AClass1.ClassInfo, PropList);

for i := 0 to ClassTypeData.PropCount - 1 do

if not (PropList[i]^.PropType^.Kind = tkMethod) then

{if Class1,2 is TControl/TWinControl on same form, its names must be unique}

if PropList[i]^.Name <> 'Name' then

if (PropList[i]^.PropType^.Kind = tkClass) then

begin

APersistent := TPersistent(GetObjectProp(AClass1, PropList[i]^.Name, TPersistent));

if APersistent <> nil then

APersistent.Assign(TPersistent(GetObjectProp(AClass2, PropList[i]^.Name, TPersistent)))

end

else

SetPropValue(AClass1, PropList[i]^.Name, GetPropValue(AClass2, PropList[i]^.Name));

finally

FreeMem(PropList, SizeOf(PPropInfo) * ClassTypeData.PropCount);

end;