如何在Delphi Form Designer中为自定义组件添加上下文菜单操作？

Question

我正在做一个自定义组件，Delphi XE2中TComponent的后代，我想右键单击它并有2个选项：Next和Previous（例如）

怎么办？请提供代码段或示例。

该选项应该在设计时出现，右键单击表单上放置的组件，现在是TComponent的后代。但如果有更好的选择来获得功能，则不需要这样做。

下一个和上一个将用于根据集合中的主题切换组件的颜色（通过所有者组件列表）。

Answer 1

您需要为组件注册自定义组件编辑器，并覆盖以下三种方法：

function GetVerbCount: Integer;
function GetVerb(Index: Integer): string; 
procedure ExecuteVerb(Index: Integer);

这是一个（非常极小的）示例，在Delphi 2007中快速抛出：

MyTestComponentPackage.dpk - 一个新的VCL包（File-＆gt; New-＆gt; Package）

package MyTestComponentPackage;

{$R *.res}
{$ALIGN 8}
{$ASSERTIONS ON}
{$BOOLEVAL OFF}
{$DEBUGINFO ON}
{$EXTENDEDSYNTAX ON}
{$IMPORTEDDATA ON}
{$IOCHECKS ON}
{$LOCALSYMBOLS ON}
{$LONGSTRINGS ON}
{$OPENSTRINGS ON}
{$OPTIMIZATION ON}
{$OVERFLOWCHECKS OFF}
{$RANGECHECKS OFF}
{$REFERENCEINFO ON}
{$SAFEDIVIDE OFF}
{$STACKFRAMES OFF}
{$TYPEDADDRESS OFF}
{$VARSTRINGCHECKS ON}
{$WRITEABLECONST OFF}
{$MINENUMSIZE 1}
{$IMAGEBASE $400000}
{$IMPLICITBUILD ON}

requires
  rtl,
  DesignIDE;

contains
  MyComponentUnit in 'MyComponentUnit.pas',
  MyCompRegUnit in 'MyCompRegUnit.pas';
end.

MyComponentUnit.pas - 用于组件代码本身的新Delphi单元（File-＆gt; New-＆gt; Unit）。 Unit声明后退/前进功能的自定义类型。该组件绝对没有任何内容，只是声明了我们可以在设计时通过弹出菜单设置的那种类型的属性。

unit MyComponentUnit;

interface

uses
  Classes;

type
  TMyComponentDirection = (cdBack, cdForward);

type
  TMyComponent=class(TComponent)
  private
    FDirection: TMyComponentDirection;
  published
    property Direction: TMyComponentDirection read FDirection write FDirection;
  end;


implementation

end.

MyCompRegUnit.pas，它实现了自定义组件编辑器并注册了组件及其编辑器：

unit MyCompRegUnit;

interface

uses
  DesignIntf, DesignEditors, Classes;

type
  TMyComponentEditor=class(TComponentEditor)
    function GetVerbCount: Integer; override;
    function GetVerb(Index: Integer): string; override;
    procedure ExecuteVerb(Index: Integer); override;
  end;

  procedure Register;

implementation

{ TMyComponentEditor }

uses
  MyComponentUnit;

// Called when component of this type is right-clicked. It's where
// you actually perform the action. The component editor is passed a reference
// to the component as "Component", which you need to cast to your specific
// component type
procedure TMyComponentEditor.ExecuteVerb(Index: Integer);
begin
  inherited;
  case Index of
    0: (Component as TMyComponent).Direction := cdBack;
    1: (Component as TMyComponent).Direction := cdForward;
  end;
end;

// Called the number of times you've stated you need in GetVerbCount.
// This is where you add your pop-up menu items
function TMyComponentEditor.GetVerb(Index: Integer): string;
begin
  case Index of
    0: Result := '&Back';
    1: Result := '&Forward';
  end;
end;

// Called when the IDE needs to populate the menu. Return the number
// of items you intend to add to the menu.
function TMyComponentEditor.GetVerbCount: Integer;
begin
  Result := 2;
end;

procedure Register;
begin
  RegisterComponents('TestStuff', [TMyComponent]);
  RegisterComponentEditor(TMyComponent, TMyComponentEditor);
end;

end.

您需要保存并构建软件包，然后在项目管理器中右键单击它并选择“安装”。它将在TestStuff组件面板页面上注册该组件。

全部保存，然后启动一个新的VCL表单应用程序。在Component Palette中，键入TMy以找到新组件，然后双击它以将其添加到新表单。在表单上右键单击它：