8

The following code (when registered in a package) gives us a component called TParentComponent registered in the pallet Test.

However, when you create a Child object using the Property Editor (provided in the same code), the IDE displays the error message Cannot create a method for an unnamed component.

What's strange is that the Child object does indeed have a name.

Here's the source:

unit TestEditorUnit;

interface

uses
  Classes, DesignEditors, DesignIntf;

type  
  TParentComponent = class;

  TChildComponent = class(TComponent)
  private
    FParent: TParentComponent;
    FOnTest: TNotifyEvent;
    procedure SetParent(const Value: TParentComponent);
  protected
    procedure SetParentComponent(AParent: TComponent); override;
  public
    destructor Destroy; override;
    function GetParentComponent: TComponent; override;
    function HasParent: Boolean; override;
    property Parent: TParentComponent read FParent write SetParent;
  published
    property OnTest: TNotifyEvent read FOnTest write FOnTest;
  end;

  TParentComponent = class(TComponent)
  private
    FChilds: TList;
  protected
    procedure GetChildren(Proc: TGetChildProc; Root: TComponent); override;
  public
    constructor Create(AOwner: TComponent); override;
    destructor Destroy; override;
  published
    property Childs: TList read FChilds;
  end;

  TParentPropertyEditor = class(TPropertyEditor)
  public
    function GetAttributes: TPropertyAttributes; override;
    function GetValue: string; override;
    procedure Edit; override;
  end;

procedure Register;

implementation

uses
  ColnEdit;

type
  TChildComponentCollectionItem = class(TCollectionItem)
  private
    FChildComponent: TChildComponent;
    function GetName: string;
    function GetOnTest: TNotifyEvent;
    procedure SetName(const Value: string);
    procedure SetOnTest(const Value: TNotifyEvent);
  protected
    property ChildComponent: TChildComponent read FChildComponent write FChildComponent;
    function GetDisplayName: string; override;
  public
    constructor Create(Collection: TCollection); override;
    destructor Destroy; override;
  published
    property Name: string read GetName write SetName;
    property OnTest: TNotifyEvent read GetOnTest write SetOnTest;
  end;

  TChildComponentCollection = class(TOwnedCollection)
  private
    FDesigner: IDesigner;
  public
    property Designer: IDesigner read FDesigner write FDesigner;
  end;

procedure Register;
begin
  RegisterClass(TChildComponent);
  RegisterNoIcon([TChildComponent]);
  RegisterComponents('Test', [TParentComponent]);
  RegisterPropertyEditor(TypeInfo(TList), TParentComponent, 'Childs', TParentPropertyEditor);
end;

{ TChildComponent }

destructor TChildComponent.Destroy;
begin
  Parent := nil;
  inherited;
end;

function TChildComponent.GetParentComponent: TComponent;
begin
  Result := FParent;
end;

function TChildComponent.HasParent: Boolean;
begin
  Result := Assigned(FParent);
end;

procedure TChildComponent.SetParent(const Value: TParentComponent);
begin
  if FParent <> Value then
  begin
    if Assigned(FParent) then
      FParent.FChilds.Remove(Self);
    FParent := Value;
    if Assigned(FParent) then
      FParent.FChilds.Add(Self);
  end;
end;

procedure TChildComponent.SetParentComponent(AParent: TComponent);
begin
  if AParent is TParentComponent then
    SetParent(AParent as TParentComponent);
end;

{ TParentComponent }

constructor TParentComponent.Create(AOwner: TComponent);
begin
  inherited;
  FChilds := TList.Create;
end;

destructor TParentComponent.Destroy;
var
  I: Integer;
begin
  for I := 0 to FChilds.Count - 1 do
    TComponent(FChilds[0]).Free;
  FChilds.Free;
  inherited;
end;

procedure TParentComponent.GetChildren(Proc: TGetChildProc; Root: TComponent);
var
  i: Integer;
begin
  for i := 0 to FChilds.Count - 1 do
    Proc(TComponent(FChilds[i]));
end;

{ TChildComponentCollectionItem }

constructor TChildComponentCollectionItem.Create(Collection: TCollection);
begin
  inherited;
  if Assigned(Collection) then
  begin
    FChildComponent := TChildComponent.Create(TComponent(TOwnedCollection(Collection).Owner).Owner);
    FChildComponent.Name := TChildComponentCollection(Collection).Designer.UniqueName(TChildComponent.ClassName);
    FChildComponent.Parent := TParentComponent(TComponent(TOwnedCollection(Collection).Owner));
  end;
end;

destructor TChildComponentCollectionItem.Destroy;
begin
  FChildComponent.Free;
  inherited;
end;

function TChildComponentCollectionItem.GetDisplayName: string;
begin
  Result := FChildComponent.Name;
end;

function TChildComponentCollectionItem.GetName: string;
begin
  Result := FChildComponent.Name;
end;

function TChildComponentCollectionItem.GetOnTest: TNotifyEvent;
begin
  Result := FChildComponent.OnTest;
end;

procedure TChildComponentCollectionItem.SetName(const Value: string);
begin
  FChildComponent.Name := Value;
end;

procedure TChildComponentCollectionItem.SetOnTest(const Value: TNotifyEvent);
begin
  FChildComponent.OnTest := Value;
end;

{ TParentPropertyEditor }

procedure TParentPropertyEditor.Edit;
var
  LCollection: TChildComponentCollection;
  i: Integer;
begin
  LCollection := TChildComponentCollection.Create(GetComponent(0), TChildComponentCollectionItem);
  LCollection.Designer := Designer;
  for i := 0 to TParentComponent(GetComponent(0)).Childs.Count - 1 do
    with TChildComponentCollectionItem.Create(nil) do
    begin
      ChildComponent := TChildComponent(TParentComponent(GetComponent(0)).Childs[i]);
      Collection := LCollection;
    end;
  ShowCollectionEditorClass(Designer, TCollectionEditor, TComponent(GetComponent(0)), LCollection, 'Childs');
end;

function TParentPropertyEditor.GetAttributes: TPropertyAttributes;
begin
  Result := [paDialog];
end;

function TParentPropertyEditor.GetValue: string;
begin
  Result := 'Childs';
end;

end.

The above source was adapated from another answer here on StackOverflow.

Any ideas why I cannot create a method for OnTest?

Thanks in advance!

4

2 回答 2

6

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。
  • 子组件需要能够在代码中通过它们的名称被引用，就像放置在设计时的任何普通组件一样；因此不是Form.CustomComponent.Children[0]，而是Form.Child1相反。
  • 因此，子组件需要在模块的源文件（Form、Frame 或 DataModule）中声明并添加到源文件中。
  • 子组件将由默认的 IDE 集合编辑器管理。
  • 因此，一个孩子需要完全被包裹在一个TCollectionItem.

当前代码的评估

您已经做得很好了，但是除了您的问题之外，代码还有几点需要改进：

  • 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。
  • 如果您从 TreeView 中删除一个子项，则旧的相应 CollectionItem 会保留，从而产生一个 AV。
  • 设计时和运行时代码不分开。

解决方案

这是您的代码的重写的工作版本，具有以下更改：

  • 特殊组件称为Master，因为Parent与 Delphi 的混淆太多Parent（已经有两种）。因此称为孩子Slave。
  • 从属被保存在一个TComponentList(unit Contnrs) 中，以在单个从属破坏的情况下自动更新列表。ComponentList 拥有从属设备。
  • 对于每个 Master，只会创建一个 Collection。这些 Master-Collection 组合保存在单独的TStockItemsObjectList 中。List 拥有库存项目，并且列表在 Finalization 部分中被释放。
  • GetNamePath被实现，以便从属显示Slave1在对象检查器中，而不是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，默认值TMethodProperty会导致您遇到错误。原因将在于Designer.GetObjectName，但我不知道确切的原因。现在GetFormMethodName被覆盖，这解决了您的问题。

评论

尚未保留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）。试着自己去实现它。

在 TreeView 中，每个 Slave 现在都是 Master 的直接子代，而不是Slaves通常在集合中看到的属性的子代：

在此处输入图像描述

为了发生这种情况，我认为TSlaves应该从TPersistent，并且 ComponentList 将被包裹在其中。那肯定是另一个不错的尝试。

组件代码

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.

包装代码

requires
  rtl,
  DesignIDE;

contains
  MasterSlave in 'MasterSlave.pas',
  MasterSlaveEdit in 'MasterSlaveEdit.pas',
  MasterSlaveReg in 'MasterSlaveReg.pas';
于 2013-05-10T02:24:42.987 回答
1

在 About.com 的“创建自定义 Delphi 组件，第 2 部分，第 4 页，共 5 页”文章中找到了足够的“解决方法” 。

完整的示例源代码在他们的文章中，并且（似乎）适用于所有版本的 Delphi。

但是，应该注意的是，此解决方案并不完美，因为它不允许您将集合编辑器与父组件和子组件分开（这意味着您必须为两个组件生成源代码才能使集合编辑器工作，并将其放在您的运行时包中）。

对于我现在的需要，这会做......但是如果有人可以直接根据我的问题中发布的示例代码找到更好的解决方案，那就太好了（如果有人提供它，我会将该答案标记为正确）。

于 2013-05-06T21:23:04.997 回答