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Mattia Massimo · Guest

Is there any simple and reliable method to copy components even using
streams ?

Fo example: I have a panel with some controls into ad i want to make an
exact copy of this panel, another instance of TPanl containing same controls
of the original. I have used streams and writecomponent and read component
but I get exception error component x has no parent. Creating the components
instances manually and then reading properties on the streams (such as
passing the instance to root param of tstream's readcomponent method) fail
to load some properties such as ttreeview items and tlistview columns even I
used the exact class type of the original.

Mattia Massimo · Guest

I will insert the source code for example:

Begin
NewTab:=TTabSheet.Create(ChatPC);
NewTab.Caption:=aRoom;
NewTab.PageControl:=ChatPC;
NewPanel:=TPanel.Create(Self);
NewPanel.Align:=alClient;
NewTab.InsertControl(NewPanel);
S:=TMemoryStream.Create;
For C:=0 To ChannelLay.ControlCount-1
Do
Begin
RegisterClass
(TPersistentClass(ChannelLay.Controls[C].ClassType));
S.WriteComponent(ChannelLay.Controls[C]);
End;
S.Seek(0,0);
For C:=0 To ChannelLay.ControlCount-1
Do
Begin

Control:=TControlClass(ChannelLay.Controls[C].ClassType).Create(Nil);
NewPanel.InsertControl(Control);
S.ReadComponent(Control);
End;
S.Free;
End

Here Channellay is a TPanel to clone, S is a TStream, NewPanel is a TPanel
where ChannelLay should copy into.

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Mattia Massimo · Guest

New code much more simple but still the ttreeview items and tlistviuew
colums not saved:

Begin
NewTab:=TTabSheet.Create(ChatPC);
NewTab.Caption:=aRoom;
NewTab.PageControl:=ChatPC;
NewPanel:=TPanel.Create(Self);
NewPanel.Align:=alClient;
NewTab.InsertControl(NewPanel);
S:=TMemoryStream.Create;
ChannelLay.Tag:=ChannelLAy.Tag+1;
For C:=0 To ChannelLay.ControlCount-1
Do
Begin
RegisterClass
(TPersistentClass(ChannelLay.Controls[C].ClassType));
S.Seek(0,soFromBeginning);
S.WriteComponent(ChannelLay.Controls[C]);
ChannelLay.Controls[C].Name:=Format('%s_%u',[Copy
(ChannelLay.Controls[C].Name,0,Pos('_',ChannelLay.Controls[C].Name)),Channel
Lay.Tag]);
Control:=TControlClass(FindClass
(ChannelLay.Controls[C].ClassName)).Create(Self);
NewPanel.InsertControl(Control);
S.Seek(0,soFromBeginning);
S.ReadComponent(Control);
End;
S.Free;
End

Note to avoid name conficts i'm usign the tag property to form the new
copied control name.
Anyone could help me pls ?

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Richard C Haven · Guest

Maybe this will help. It will NOT copy TreeView nodes or StringGrid
cells, but you can add code for that.

Cheers

procedure AssignAllProperties(Source, Target : TPersistent);
var
ThisProp : PPropInfo;
PropInfos : TPropList;
Counter : System.Integer;
begin
TypInfo.GetPropInfos(Source.ClassInfo, @PropInfos);
for Counter := 0 to GetTypeData(Source.ClassInfo)^.PropCount - 1 do
begin
ThisProp := PropInfos[Counter];
if (ThisProp.Name = 'Name') and (ThisProp.PropType^.Kind =
tkString) then
SetStrProp(Target, ThisProp, GetStrProp(Source, ThisProp) +
'Clone')
else
begin
case ThisProp.PropType^.Kind of
tkInteger, tkChar, tkEnumeration, tkSet, tkClass, tkWChar :
SetOrdProp(Target, ThisProp, GetOrdProp(Source,
ThisProp));
tkFloat : SetFloatProp(Target, ThisProp,
GetFloatProp(Source, ThisProp));
tkString, tkLString, tkWString :
SetStrProp(Target, ThisProp, GetStrProp(Source,
ThisProp));

tkVariant : SetVariantProp(Target, ThisProp,
GetVariantProp(Source, ThisProp));
tkMethod : SetMethodProp(Target, ThisProp,
GetMethodProp(Source, ThisProp));
tkInt64 : SetInt64Prop(Target, ThisProp,
GetInt64Prop(Source, ThisProp));
end;
end;
end;
end;

procedure ClonePersistent(Source : TPersistent; var Target : TPersistent);
var
ComponentClass : TComponentClass;
begin
if Target = nil then
begin
if Source is TComponent then
begin
ComponentClass := TComponentClass(Source.ClassType);
Target := ComponentClass.Create(TComponent(Source).Owner);
TComponent(Target).Name := TComponent(Source).Name + 'Clone';
end
else
Target := Source.Create;
end;

if Source is TControl then
TControl(Target).Parent := TControl(Source).Parent;

AssignAllProperties(Source, Target);
end;

Mattia Massimo wrote:

Mattia Massimo · Guest

Yes this is fine, but is there also a method just like the copy and paste @
designtime in delphi ide ? This method should copy everithing. I think
should be something using streaming capabilities.

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