我需要为我的组件添加操作支持,它是一个按钮组件,但我想无论是什么类型的组件都是一样的。任何信息或如何操作的帮助都会有所帮助。
我需要为我的组件添加操作支持,它是一个按钮组件,但我想无论是什么类型的组件都是一样的。任何信息或如何操作的帮助都会有所帮助。
unit Unit1;
interface
uses
Classes, ActnList, SysUtils;
type
TColumn = class;
TColumnActionLink = class(TActionLink)
protected
FClient: TColumn;
procedure AssignClient(AClient: TObject); override;
function IsCaptionLinked: Boolean; override;
function IsEnabledLinked: Boolean; override;
function IsOnExecuteLinked: Boolean; override;
function IsVisibleLinked: Boolean; override;
procedure SetCaption(const Value: String); override;
procedure SetEnabled(Value: Boolean); override;
procedure SetOnExecute(Value: TNotifyEvent); override;
procedure SetVisible(Value: Boolean); override;
end;
TColumnActionLinkClass = class of TColumnActionLink;
TColumn = class(TCollectionItem)
private
FActionLink: TColumnActionLink;
FGrid: TComponent;
FOnTitleClick: TNotifyEvent;
FReadOnly: Boolean;
FTitle: String;
FVisible: Boolean;
function DefaultTitleCaption: String;
procedure DoActionChange(Sender: TObject);
function GetAction: TBasicAction;
function IsOnTitleClickStored: Boolean;
function IsReadOnlyStored: Boolean;
function IsVisibleStored: Boolean;
procedure SetAction(Value: TBasicAction);
protected
procedure ActionChanged(Sender: TObject; CheckDefaults: Boolean); dynamic;
procedure DoTitleClick; virtual;
function GetActionLinkClass: TColumnActionLinkClass; virtual;
property ActionLink: TColumnActionLink read FActionLink write FActionLink;
public
destructor Destroy; override;
procedure InitiateAction; virtual;
published
property Action: TBasicAction read GetAction write SetAction;
property OnTitleClick: TNotifyEvent read FOnTitleClick write FOnTitleClick
stored IsOnTitleClickStored;
property ReadOnly: Boolean read FReadOnly write FReadOnly
stored IsReadOnlyStored;
property Title: String read FTitle write FTitle;
property Visible: Boolean read FVisible write FVisible
stored IsVisibleStored;
end;
implementation
{ TColumnActionLink }
procedure TColumnActionLink.AssignClient(AClient: TObject);
begin
FClient := TColumn(AClient);
end;
function TColumnActionLink.IsCaptionLinked: Boolean;
begin
Result := inherited IsCaptionLinked and (Action is TCustomAction) and
(FClient.Title = TCustomAction(Action).Caption);
end;
function TColumnActionLink.IsEnabledLinked: Boolean;
begin
Result := inherited IsEnabledLinked and (Action is TCustomAction) and
(FClient.ReadOnly <> TCustomAction(Action).Enabled);
end;
function TColumnActionLink.IsOnExecuteLinked: Boolean;
begin
Result := inherited IsOnExecuteLinked and
(@FClient.OnTitleClick = @Action.OnExecute);
end;
function TColumnActionLink.IsVisibleLinked: Boolean;
begin
Result := inherited IsVisibleLinked and (Action is TCustomAction) and
(FClient.Visible = TCustomAction(Action).Visible);
end;
procedure TColumnActionLink.SetCaption(const Value: string);
begin
if IsCaptionLinked then
FClient.Title := Value;
end;
procedure TColumnActionLink.SetEnabled(Value: Boolean);
begin
if IsEnabledLinked then
FClient.ReadOnly := not Value;
end;
procedure TColumnActionLink.SetOnExecute(Value: TNotifyEvent);
begin
if IsOnExecuteLinked then
FClient.OnTitleClick := Value;
end;
procedure TColumnActionLink.SetVisible(Value: Boolean);
begin
if IsVisibleLinked then
FClient.Visible := Value;
end;
{ TColumn }
procedure TColumn.ActionChanged(Sender: TObject; CheckDefaults: Boolean);
begin
if Sender is TCustomAction then
with TCustomAction(Sender) do
begin
if not CheckDefaults or (Caption = DefaultTitleCaption) then
FTitle := Caption;
if not CheckDefaults or (not ReadOnly) then
ReadOnly := not Enabled;
if not CheckDefaults or not Assigned(FOnTitleClick) then
FOnTitleClick := OnExecute;
if not CheckDefaults or (Self.Visible = True) then
Self.Visible := Visible;
Changed(False);
end;
end;
function TColumn.DefaultTitleCaption: String;
begin
Result := 'Column' + IntToStr(Index);
end;
destructor TColumn.Destroy;
begin
FreeAndNil(FActionLink);
inherited Destroy;
end;
procedure TColumn.DoActionChange(Sender: TObject);
begin
if Sender = Action then
ActionChanged(Sender, False);
end;
procedure TColumn.DoTitleClick;
begin
if Assigned(FOnTitleClick) then
if (Action <> nil) and (@FOnTitleClick <> @Action.OnExecute) then
FOnTitleClick(Self)
else if FActionLink = nil then
FOnTitleClick(Self)
else if FActionLink <> nil then
if (FGrid <> nil) and not (csDesigning in FGrid.ComponentState) then
begin
if not FActionLink.Execute(FGrid) then
FOnTitleClick(Self);
end
else
if not FActionLink.Execute(nil) then
FOnTitleClick(Self);
end;
function TColumn.GetAction: TBasicAction;
begin
if FActionLink <> nil then
Result := FActionLink.Action
else
Result := nil;
end;
function TColumn.GetActionLinkClass: TColumnActionLinkClass;
begin
Result := TColumnActionLink;
end;
procedure TColumn.InitiateAction;
begin
if FActionLink <> nil then
FActionLink.Update;
end;
function TColumn.IsOnTitleClickStored: Boolean;
begin
Result := (FActionLink = nil) or not ActionLink.IsOnExecuteLinked;
end;
function TColumn.IsReadOnlyStored: Boolean;
begin
Result := (FActionLink = nil) or not FActionLink.IsEnabledLinked;
if Result then
Result := FReadOnly;
end;
function TColumn.IsVisibleStored: Boolean;
begin
Result := (FActionLink = nil) or not FActionLink.IsVisibleLinked;
if Result then
Result := not Visible;
end;
procedure TColumn.SetAction(Value: TBasicAction);
begin
if Value = nil then
FreeAndNil(FActionLink)
else
begin
if FActionLink = nil then
FActionLink := GetActionLinkClass.Create(Self);
FActionLink.Action := Value;
FActionLink.OnChange := DoActionChange;
ActionChanged(Value, csLoading in Value.ComponentState);
if FGrid <> nil then
Value.FreeNotification(FGrid);
end;
Changed(False);
end;
end.
动作组件可分配给任意组件的操作属性。但由于解释编写此类动作组件所涉及的所有内容相当全面,因此我将在下面提供示例以使自己更容易。
假设您想创建一个控件,提供缩放功能,并且您还希望相应的ZoomIn和ZoomOut操作可分配给工具栏按钮。
unit Zoomer;
interface
uses
Classes, Controls, ActnList, Forms, Menus, Windows;
type
TZoomer = class;
TZoomAction = class(TCustomAction)
private
FZoomer: TZoomer;
procedure SetZoomer(Value: TZoomer);
protected
function GetZoomer(Target: TObject): TZoomer;
procedure Notification(AComponent: TComponent; Operation: TOperation);
override;
public
destructor Destroy; override;
function HandlesTarget(Target: TObject): Boolean; override;
procedure UpdateTarget(Target: TObject); override;
published
property Caption;
property Enabled;
property HelpContext;
property HelpKeyword;
property HelpType;
property Hint;
property ImageIndex;
property ShortCut;
property SecondaryShortCuts;
property Visible;
property OnExecute; { This property could be omitted. But if you want to be
able to override the default behavior of this action
(zooming in on a TZoomer component), then you need to
assign this event. From within the event handler
you could invoke the default behavior manually. }
property OnHint;
property OnUpdate;
property Zoomer: TZoomer read FZoomer write SetZoomer;
end;
TZoomInAction = class(TZoomAction)
public
constructor Create(AOwner: TComponent); override;
procedure ExecuteTarget(Target: TObject); override;
end;
TZoomer = class(TCustomControl)
public
procedure ZoomIn;
end;
procedure Register;
implementation
procedure Register;
begin
RegisterComponents('RoyMKlever', [TZoomer]);
RegisterActions('Zoomer', [TZoomInAction], nil);
end;
{ TZoomAction }
destructor TZoomAction.Destroy;
begin
if FZoomer <> nil then
FZoomer.RemoveFreeNotification(Self);
inherited Destroy;
end;
function TZoomAction.GetZoomer(Target: TObject): TZoomer;
begin
if FZoomer <> nil then
Result := FZoomer
else if (Target is TZoomer) and TZoomer(Target).Focused then
Result := TZoomer(Target)
else if Screen.ActiveControl is TZoomer then
Result := TZoomer(Screen.ActiveControl)
else
{ This should not happen! HandlesTarget is called before ExecuteTarget,
or the action is disabled }
Result := nil;
end;
function TZoomAction.HandlesTarget(Target: TObject): Boolean;
begin
Result := ((FZoomer <> nil) and FZoomer.Enabled) or
((FZoomer = nil) and (Target is TZoomer) and TZoomer(Target).Focused) or
((Screen.ActiveControl is TZoomer) and Screen.ActiveControl.Enabled);
end;
procedure TZoomAction.Notification(AComponent: TComponent;
Operation: TOperation);
begin
inherited Notification(AComponent, Operation);
if (Operation = opRemove) and (AComponent = FZoomer) then
FZoomer := nil;
end;
procedure TZoomAction.SetZoomer(Value: TZoomer);
begin
if FZoomer <> Value then
begin
if FZoomer <> nil then
FZoomer.RemoveFreeNotification(Self);
FZoomer := Value;
if FZoomer <> nil then
FZoomer.FreeNotification(Self);
end;
end;
procedure TZoomAction.UpdateTarget(Target: TObject);
begin
Enabled := HandlesTarget(Target);
end;
{ TZoomInAction }
constructor TZoomInAction.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
Caption := 'Zoom in';
Hint := 'Zoom in|Zooms in on the selected zoomer control';
ShortCut := Menus.ShortCut(VK_ADD, [ssCtrl]);
end;
procedure TZoomInAction.ExecuteTarget(Target: TObject);
begin
GetZoomer(Target).ZoomIn;
{ For safety, you cóuld check if GetZoomer <> nil. See remark in GetZoomer. }
end;
{ TZoomer }
procedure TZoomer.ZoomIn;
begin
{ implementation of zooming in }
end;
end.
激活此操作(通过单击工具栏按钮或选择菜单项)按以下优先顺序调用ZoomIn例程:
随后,ZoomOut操作将被简单添加:
type
TZoomOutAction = class(TZoomAction)
public
constructor Create(AOwner: TComponent); override;
procedure ExecuteTarget(Target: TObject); override;
end;
{ TZoomOutAction }
constructor TZoomOutAction.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
Caption := 'Zoom out';
Hint := 'Zoom out|Zooms out on the selected zoomer control';
ShortCut := Menus.ShortCut(VK_SUBTRACT, [ssCtrl]);
end;
procedure TZoomOutAction.ExecuteTarget(Target: TObject);
begin
GetZoomer(Target).ZoomOut;
end;
在TControl类中实现了基本的操作支持,因此在最简单的情况下,您只需要继承您的组件从TControl后代,并将Action
属性声明为发布即可,例如:
type
TMyGraphicControl = class(TGraphicControl)
published
property Action;
end;