学习官方示例 - TApplication.Icon

本例同时包含了 TOpenPictureDialog 控件的一些用法.

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代码文件:

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unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtDlgs, StdCtrls;

type
  TForm1 = class(TForm)
    OpenPictureDialog1: TOpenPictureDialog;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var 
  Done: Boolean;
begin
  OpenPictureDialog1.DefaultExt := GraphicExtension(TIcon);
  OpenPictureDialog1.FileName := GraphicFileMask(TIcon);
  OpenPictureDialog1.Filter := GraphicFilter(TIcon);
  OpenPictureDialog1.Options := [ofFileMustExist, ofHideReadOnly, ofNoChangeDir];

  Done := False;
  while not Done do {这个循环是让你必须找一个}
  begin
    if OpenPictureDialog1.Execute then
      if not (ofExtensionDifferent in OpenPictureDialog1.Options) then
        begin
          Application.Icon.LoadFromFile(OpenPictureDialog1.FileName);
          Done := True;
        end
    else
      Done := True;
  end;
end;

end.

窗体文件:

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object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 106
  ClientWidth = 142
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  PixelsPerInch = 96
  TextHeight = 13
  object Button1: TButton
    Left = 32
    Top = 56
    Width = 75
    Height = 25
    Caption = 'Button1'
    TabOrder = 0
    OnClick = Button1Click
  end
  object OpenPictureDialog1: TOpenPictureDialog
    Left = 56
    Top = 24
  end
end