delphi – 如何为某个类型的所有实例实现自己的自定义属性编辑器

我不想在这里提出这个问题,希望有人能为我回答,所以我自己做了研究来解决我的问题,我想分享这个迷你项目所涉及的独特经验,因为我相信别人都是沮丧的同样的事情.

自定义属性编辑器,对话框和组件编辑器有许多不同的可能性.这特别要求一个TDateTimeProperty后代.这将允许您在保持DateTime格式的同时,直接在Object Inspector中以纯文本(String)的形式编辑属性的值.

我假设你已经有一个关于创建自定义组件和一个包,您可以在其中发布此属性编辑器的一般知识,因为这是一个教训,我将不会介绍.这就需要在注册过程中放置??一行代码,但稍后我们再来看看.

首先,您需要在您的组件注册的设计时包中创建一个新表单.将单位命名为DateTimeProperty.pas,并将表单DateTimeDialog命名(从而使表单的类TDateTimeDialog).放置任何您需要的控件,在这种情况下,TMonthCalendar,TDateTimePicker(Kind设置为dtkTime)和2个TBitBtn控件,一个标记为“OK”,其中mrOK为ModalResult,另一个标记为“取消与malCancel的ModalResult”.

你的单位应该是这样的：

unit DateTimeProperty;

interface

uses
  Winapi.Windows,Winapi.Messages,System.SysUtils,System.Variants,System.Classes,Vcl.Graphics,Vcl.Controls,Vcl.Forms,Vcl.Dialogs,Vcl.ComCtrls,Vcl.StdCtrls,Vcl.Buttons;

type
  TDateTimeDialog = class(TForm)
    dtDate: TMonthCalendar;
    dtTime: TDateTimePicker;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
  private

  public

  end;         

var
  DateTimeDialog: TDateTimeDialog;

implementation

{$R *.dfm}

end.

这里是DFM代码：

object DateTimeDialog: TDateTimeDialog
  Left = 591
  Top = 158
  BorderIcons = [biSystemMenu]
  BorderStyle = bsToolWindow
  Caption = 'Pick Date/Time'
  ClientHeight = 231
  ClientWidth = 241
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poScreenCenter
  DesignSize = (
    241
    231)
  PixelsPerInch = 96
  TextHeight = 13
  object dtDate: TMonthCalendar
    Left = 8
    Top = 31
    Width = 225
    Height = 166
    Anchors = [akLeft,akRight,akBottom]
    Date = 41261.901190613430000000
    TabOrder = 1
  end
  object dtTime: TDateTimePicker
    Left = 8
    Top = 8
    Width = 113
    Height = 21
    Date = 41261.000000000000000000
    Time = 41261.000000000000000000
    Kind = dtkTime
    TabOrder = 2
  end
  object BitBtn1: TBitBtn
    Left = 158
    Top = 200
    Width = 75
    Height = 25
    Caption = 'OK'
    Default = True
    ModalResult = 1
    TabOrder = 0
  end
  object BitBtn2: TBitBtn
    Left = 77
    Top = 200
    Width = 75
    Height = 25
    Caption = 'Cancel'
    ModalResult = 2
    TabOrder = 3
  end
end

现在,将DesignEditors和DesignIntf??添加到uses子句中.确保您在此设计时间包的要求中声明了DesignIDE.这是发布任何属性编辑器所必需的.

在表单中,使用属性getter和setter创建一个名为DateTime的类型为TDateTime的新的公共属性.此属性将允许您轻松读/写完整选择实际表示的TDateTime值.所以你应该用你的形式：

private
  function GetDateTime: TDateTime;
  procedure SetDateTime(const Value: TDateTime);
public
  property DateTime: TDateTime read GetDateTime write SetDateTime;

....

function TDateTimeDialog.GetDateTime: TDateTime;
begin
  Result:= Int(dtDate.Date) + Frac(dtTime.Time);
end;

procedure TDateTimeDialog.SetDateTime(const Value: TDateTime);
begin
  dtDate.Date:= Value;
  dtTime.DateTime:= Value;
end;

接下来我们需要添加实际的属性编辑器类.在刚刚实施的{$R * .dfm}下面创建这个类：

type
  TDateTimeEditor = class(TDateTimeProperty)
  public
    procedure Edit; override;
    function GetAttributes: TPropertyAttributes; override;
    function GetValue: String; override;
    procedure SetValue(const Value: String); override;
  end;

procedure TDateTimeEditor.Edit;
var
  F: TDateTimeDialog;
begin
  //Initialize the property editor window
  F:= TDateTimeDialog.Create(Application);
  try
    F.DateTime:= GetFloatValue;
    if F.ShowModal = mrOK then begin
      SetFloatValue(F.DateTime);
    end;
  finally
    F.Free;
  end;
end;

function TDateTimeEditor.GetAttributes: TPropertyAttributes;
begin
  //Makes the small button show to the right of the property
  Result := inherited GetAttributes + [paDialog];
end;

function TDateTimeEditor.GetValue: String;
begin
  //Returns the string which should show in Object Inspector
  Result:= FormatDateTime('m/d/yy h:nn:ss ampm',GetFloatValue);
end;

procedure TDateTimeEditor.SetValue(const Value: String);
begin
  //Assigns the string typed in Object Inspector to the property
  inherited;
end;

最后,我们需要添加一个注册过程来执行这个新的属性编辑器的实际注册：

procedure Register;
begin
  RegisterPropertyEditor(TypeInfo(TDateTime),nil,'',TDateTimeEditor);
end;

现在在对RegisterPropertyEditor的这个调用中有一个重要的理解.由于第2和第3个参数为零和空字符串,这意味着编辑器将应用于TDateTime的所有实例.查看此过程以获取有关使特定于某些组件和属性实例的更多信息.

这是安装后的最终结果…

贡献的定制财产编辑的一些好的资源如下：

> how to make custom component property?
> http://delphi.about.com/library/bluc/text/uc092501d.htm
> http://www.sandownet.com/propedit.html