Today I want to show a few samples how you can use the extended dialogs from MS Windows (Find Files, Find Computer, Select Icon etc) in own code. 

Usually the MessageDlg is most used from standard dialogs but inside of Windows you'll find a lot of other useful dialogs too. 

The any such dialog is declared in the Shell32.dll library and you can use it so: 

1. Select an icon 
this dialog is a same which you'll see when you'll edit an icon of any lnk-file (icon on desktop, for example) 

Declaration: 
function PickIconDlgA(OwnerWnd: HWND; lpstrFile: PAnsiChar; var nMaxFile: LongInt; var lpdwIconIndex: LongInt): LongBool; stdcall; external 
'SHELL32.DLL' index 62; 

Example (icon of current application will be changed!): 

procedure TForm1.Button4Click(Sender: TObject); 
var 
  FileName: array[0..MAX_PATH-1] of Char; 
  Size, Index: LongInt; 
begin 
  Size := MAX_PATH; 
  FileName := 'c:\windows\system\shell32.dll'; 
  if PickIconDlgA(0, FileName, Size, Index) then 
  begin 
    if (Index <> -1) then 
      Application.Icon.Handle := ExtractIcon(hInstance, FileName, Index); 
  end; 
end; 


Of course, you can define any other file and in the dialog you'll see available icons of this executable file. 

2. Find Computer 

Declaration: 
function SHFindComputer(pidlRoot: PItemIDList; pidlSavedSearch: PItemIDList): Boolean; stdcall; external 'Shell32.dll' index 91; 

Example: 

begin 
  SHFindComputer(nil, nil); 
end; 

3. Find Files 

Declaration: 
function SHFindFiles(pidlRoot: PItemIDList; pidlSavedSearch: PItemIDList): Boolean; stdcall; external 'Shell32.dll' index 90; 

Example: 

begin 
  SHFindFiles(nil, nil); 
end; 

Here the first parameter is a folder where you want to begin a search (nil is a Desktop). The second parameter allow to define a previous saved state of search process. 

IMPORTANT: 
Note that SHFindFiles and SHFindComputer are not modal dialogs (these dialogs will be started in separated thread) so the result of function will be  True  if dialog is created succesfully. 

4. Shutdown dialog 

Declaration: 
procedure ExitWindowsDialog(ParentWnd: HWND); stdcall; external 'Shell32.dll' index 60; 

Example: 

begin 
  ExitWindowsDialog(0) 
end; 


5. RestartDialog 
this dialog allow to ask end-user about Windows restarting and is used when changes are made to system that require a shutdown/restart before they will take effect. 

Declaration: 
function RestartDialog(ParentWnd: HWND; Reason: PAnsiChar; Flags: LongInt): LongInt; stdcall; external 'Shell32.dll' index 59; 

Example: 
begin 
  if RestartDialog(0, 'I want to call a RestartDialog ', EW_RESTARTWINDOWS) 
= IDYES then 
    ShowMessage('succesfully started') 
end; 

You can define any reason of restarting (second parameter - additionally to default text or nil for default only) and use the another flag (one from the next available): 

EWX_LOGOFF 
EWX_SHUTDOWN 
EWX_REBOOT 
EW_RESTARTWINDOWS 
EW_REBOOTSYSTEM 
EW_EXITANDEXECAPP 

This dialog is very useful for application which have embedded install procedure. 

6. OutOfSpace 
Will display a notification dialog about "Out Of Space" for some defined drive. 

Declaration: 
procedure SHHandleDiskFull(Owner: HWND; Drive: UINT); stdcall; external 
'Shell32.dll' index 185; 

Example: 

begin 
  SHHandleDiskFull(0, 2); 
end; 

Note that second parameter is Drive number where 0 is A:, 1 is B:, 2 is C: etc 

Of course, in the Shell32.dll you'll find other dialogs too (Object Properties, Map Network Drive, Browse For Folder etc) and you can use these dialogs without any problems. 

IMPORTANT: 

Don't forget to add ShlObj and ShellAPI units into uses-clause.

    本文转自 OldHawk  博客园博客，原文链接：http://www.cnblogs.com/taobataoma/archive/2007/08/20/862457.html，如需转载请自行联系原作者