设计时间要求汇总
- 您想要或需要一个能够容纳多个子组件的自定义组件。
- 这些子组件将由该自定义组件创建。
- 子组件需要能够像设计时放置的任何普通组件一样在代码中通过其名称进行引用；因此不
Form.CustomComponent.Children[0], but Form.Child1反而。
- 因此，子组件需要在模块（Form、Frame 或 DataModule）的源文件中声明并添加到其中。
- 子组件由默认的 IDE 集合编辑器管理。
- 因此，孩子需要被完全包裹在一个
TCollectionItem.
当前代码的评估
您已经进展顺利，但除了您的问题之外，代码还有一些需要改进的地方：
- 您创建的集合永远不会被释放。
- 每次显示集合编辑器时都会创建一个新集合。
- 如果从 TreeView 中删除子项，则旧的相应 CollectionItem 会保留，从而生成 AV。
- 设计时和运行时代码没有分开。
Solution
这是代码的重写的工作版本，具有以下更改：
- 这个特殊的组件称为
Master， 因为Parent与 Delphi 的混淆太多Parent（已经有两种）。因此孩子被称为Slave.
- 奴隶被关在一个
TComponentList (unit Contnrs）以在单个从属破坏的情况下自动更新列表。 ComponentList 拥有从属组件。
- 对于每一位大师，只会创建一个集合。这些主收藏组合保存在单独的
TStockItems对象列表。该列表拥有库存项目，并且该列表在“最终确定”部分中被释放。
-
GetNamePath被实现，以便从属显示为Slave1在对象检查器中，而不是作为SlaveWrappers(0).
- 为 TSlaveWrapper 类的事件添加了一个额外的属性编辑器。不知何故
GetFormMethodName默认的TMethodProperty导致您收到错误。原因将在于Designer.GetObjectName，但我不知道具体原因。现在GetFormMethodName被覆盖，这解决了您问题中的问题。
Remarks
对集合中项目顺序所做的更改（使用集合编辑器的箭头按钮）尚未保留。尝试自己去实现它。
在 TreeView 中，每个 Slave 现在都是 Master 的直接子级，而不是 Master 的子级Slaves属性，如通常在集合中看到的那样：
为了实现这一点，我认为TSlaves应该从TPersistent，并且 ComponentList 将被包装在其中。这肯定是另一个不错的尝试。
元件代码
unit MasterSlave;
interface
uses
Classes, Contnrs;
type
TMaster = class;
TSlave = class(TComponent)
private
FMaster: TMaster;
FOnTest: TNotifyEvent;
procedure SetMaster(Value: TMaster);
protected
procedure SetParentComponent(AParent: TComponent); override;
public
function GetParentComponent: TComponent; override;
function HasParent: Boolean; override;
property Master: TMaster read FMaster write SetMaster;
published
property OnTest: TNotifyEvent read FOnTest write FOnTest;
end;
TSlaves = class(TComponentList)
private
function GetItem(Index: Integer): TSlave;
procedure SetItem(Index: Integer; Value: TSlave);
public
property Items[Index: Integer]: TSlave read GetItem write SetItem; default;
end;
TMaster = class(TComponent)
private
FSlaves: TSlaves;
protected
procedure GetChildren(Proc: TGetChildProc; Root: TComponent); override;
public
constructor Create(AOwner: TComponent); override;
destructor Destroy; override;
published
property Slaves: TSlaves read FSlaves;
end;
implementation
{ TSlave }
function TSlave.GetParentComponent: TComponent;
begin
Result := FMaster;
end;
function TSlave.HasParent: Boolean;
begin
Result := FMaster <> nil;
end;
procedure TSlave.SetMaster(Value: TMaster);
begin
if FMaster <> Value then
begin
if FMaster <> nil then
FMaster.FSlaves.Remove(Self);
FMaster := Value;
if FMaster <> nil then
FMaster.FSlaves.Add(Self);
end;
end;
procedure TSlave.SetParentComponent(AParent: TComponent);
begin
if AParent is TMaster then
SetMaster(TMaster(AParent));
end;
{ TSlaves }
function TSlaves.GetItem(Index: Integer): TSlave;
begin
Result := TSlave(inherited Items[Index]);
end;
procedure TSlaves.SetItem(Index: Integer; Value: TSlave);
begin
inherited Items[Index] := Value;
end;
{ TMaster }
constructor TMaster.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
FSlaves := TSlaves.Create(True);
end;
destructor TMaster.Destroy;
begin
FSlaves.Free;
inherited Destroy;
end;
procedure TMaster.GetChildren(Proc: TGetChildProc; Root: TComponent);
var
I: Integer;
begin
for I := 0 to FSlaves.Count - 1 do
Proc(FSlaves[I]);
end;
end.
编辑器代码
unit MasterSlaveEdit;
interface
uses
Classes, SysUtils, MasterSlave, Contnrs, DesignEditors, DesignIntf, ColnEdit;
type
TMasterEditor = class(TComponentEditor)
private
function Master: TMaster;
public
procedure ExecuteVerb(Index: Integer); override;
function GetVerb(Index: Integer): String; override;
function GetVerbCount: Integer; override;
end;
TMasterProperty = class(TPropertyEditor)
private
function Master: TMaster;
public
procedure Edit; override;
function GetAttributes: TPropertyAttributes; override;
function GetValue: String; override;
end;
TOnTestProperty = class(TMethodProperty)
private
function Slave: TSlave;
public
function GetFormMethodName: String; override;
end;
TSlaveWrapper = class(TCollectionItem)
private
FSlave: TSlave;
function GetName: String;
function GetOnTest: TNotifyEvent;
procedure SetName(const Value: String);
procedure SetOnTest(Value: TNotifyEvent);
protected
function GetDisplayName: String; override;
public
constructor Create(Collection: TCollection); override;
constructor CreateSlave(Collection: TCollection; ASlave: TSlave);
destructor Destroy; override;
function GetNamePath: String; override;
published
property Name: String read GetName write SetName;
property OnTest: TNotifyEvent read GetOnTest write SetOnTest;
end;
TSlaveWrappers = class(TOwnedCollection)
private
function GetItem(Index: Integer): TSlaveWrapper;
public
property Items[Index: Integer]: TSlaveWrapper read GetItem; default;
end;
implementation
type
TStockItem = class(TComponent)
protected
Collection: TSlaveWrappers;
Designer: IDesigner;
Master: TMaster;
procedure Notification(AComponent: TComponent; Operation: TOperation);
override;
public
destructor Destroy; override;
end;
TStockItems = class(TObjectList)
private
function GetItem(Index: Integer): TStockItem;
protected
function CollectionOf(AMaster: TMaster; Designer: IDesigner): TCollection;
function Find(ACollection: TCollection): TStockItem;
property Items[Index: Integer]: TStockItem read GetItem;
default;
end;
var
FStock: TStockItems = nil;
function Stock: TStockItems;
begin
if FStock = nil then
FStock := TStockItems.Create(True);
Result := FStock;
end;
{ TStockItem }
destructor TStockItem.Destroy;
begin
Collection.Free;
inherited Destroy;
end;
procedure TStockItem.Notification(AComponent: TComponent;
Operation: TOperation);
var
I: Integer;
begin
inherited Notification(AComponent, Operation);
if Operation = opRemove then
for I := 0 to Collection.Count - 1 do
if Collection[I].FSlave = AComponent then
begin
Collection[I].FSlave := nil;
Collection.Delete(I);
Break;
end;
end;
{ TStockItems }
function TStockItems.CollectionOf(AMaster: TMaster;
Designer: IDesigner): TCollection;
var
I: Integer;
Item: TStockItem;
begin
Result := nil;
for I := 0 to Count - 1 do
if Items[I].Master = AMaster then
begin
Result := Items[I].Collection;
Break;
end;
if Result = nil then
begin
Item := TStockItem.Create(nil);
Item.Master := AMaster;
Item.Designer := Designer;
Item.Collection := TSlaveWrappers.Create(AMaster, TSlaveWrapper);
for I := 0 to AMaster.Slaves.Count - 1 do
begin
TSlaveWrapper.CreateSlave(Item.Collection, AMaster.Slaves[I]);
Item.FreeNotification(AMaster.Slaves[I]);
end;
Add(Item);
Result := Item.Collection;
end;
end;
function TStockItems.GetItem(Index: Integer): TStockItem;
begin
Result := TStockItem(inherited Items[Index]);
end;
function TStockItems.Find(ACollection: TCollection): TStockItem;
var
I: Integer;
begin
Result := nil;
for I := 0 to Count - 1 do
if Items[I].Collection = ACollection then
begin
Result := Items[I];
Break;
end;
end;
{ TMasterEditor }
procedure TMasterEditor.ExecuteVerb(Index: Integer);
begin
case Index of
0: ShowCollectionEditor(Designer, Master,
Stock.CollectionOf(Master, Designer), 'Slaves');
end;
end;
function TMasterEditor.GetVerb(Index: Integer): String;
begin
case Index of
0: Result := 'Edit slaves...';
else
Result := '';
end;
end;
function TMasterEditor.GetVerbCount: Integer;
begin
Result := 1;
end;
function TMasterEditor.Master: TMaster;
begin
Result := TMaster(Component);
end;
{ TMasterProperty }
procedure TMasterProperty.Edit;
begin
ShowCollectionEditor(Designer, Master,
Stock.CollectionOf(Master, Designer), 'Slaves');
end;
function TMasterProperty.GetAttributes: TPropertyAttributes;
begin
Result := [paDialog];
end;
function TMasterProperty.GetValue: String;
begin
Result := Format('(%s)', [Master.Slaves.ClassName]);
end;
function TMasterProperty.Master: TMaster;
begin
Result := TMaster(GetComponent(0));
end;
{ TOnTestProperty }
function TOnTestProperty.GetFormMethodName: String;
begin
Result := Slave.Name + GetTrimmedEventName;
end;
function TOnTestProperty.Slave: TSlave;
begin
Result := TSlaveWrapper(GetComponent(0)).FSlave;
end;
{ TSlaveWrapper }
constructor TSlaveWrapper.Create(Collection: TCollection);
begin
CreateSlave(Collection, nil);
end;
constructor TSlaveWrapper.CreateSlave(Collection: TCollection; ASlave: TSlave);
var
Item: TStockItem;
begin
inherited Create(Collection);
if ASlave = nil then
begin
Item := Stock.Find(Collection);
FSlave := TSlave.Create(Item.Master.Owner);
FSlave.Name := Item.Designer.UniqueName(TSlave.ClassName);
FSlave.Master := Item.Master;
FSlave.FreeNotification(Item);
end
else
FSlave := ASlave;
end;
destructor TSlaveWrapper.Destroy;
begin
FSlave.Free;
inherited Destroy;
end;
function TSlaveWrapper.GetDisplayName: String;
begin
Result := Name;
end;
function TSlaveWrapper.GetName: String;
begin
Result := FSlave.Name;
end;
function TSlaveWrapper.GetNamePath: String;
begin
Result := FSlave.GetNamePath;
end;
function TSlaveWrapper.GetOnTest: TNotifyEvent;
begin
Result := FSlave.OnTest;
end;
procedure TSlaveWrapper.SetName(const Value: String);
begin
FSlave.Name := Value;
end;
procedure TSlaveWrapper.SetOnTest(Value: TNotifyEvent);
begin
FSlave.OnTest := Value;
end;
{ TSlaveWrappers }
function TSlaveWrappers.GetItem(Index: Integer): TSlaveWrapper;
begin
Result := TSlaveWrapper(inherited Items[Index]);
end;
initialization
finalization
FStock.Free;
end.
注册码
unit MasterSlaveReg;
interface
uses
Classes, MasterSlave, MasterSlaveEdit, DesignIntf;
procedure Register;
implementation
procedure Register;
begin
RegisterClass(TSlave);
RegisterNoIcon([TSlave]);
RegisterComponents('Samples', [TMaster]);
RegisterComponentEditor(TMaster, TMasterEditor);
RegisterPropertyEditor(TypeInfo(TSlaves), TMaster, 'Slaves',
TMasterProperty);
RegisterPropertyEditor(TypeInfo(TNotifyEvent), TSlaveWrapper, 'OnTest',
TOnTestProperty);
end;
end.
封装代码
requires
rtl,
DesignIDE;
contains
MasterSlave in 'MasterSlave.pas',
MasterSlaveEdit in 'MasterSlaveEdit.pas',
MasterSlaveReg in 'MasterSlaveReg.pas';
