获取程序大图标方案

获取文件的图标

在win7的文件状态栏中能显示最大256x256的程序应用图标。

在XP下测试无法正常获取256的巨型图标

Shell提供了一个函数 SHGetFileInfo 可以获取文件信息，在使用此函数有需要处理Icon句柄的释放（DestroyIcon），否则每次会有3个GDI句柄泄漏问题。

使用此函数后会一次性产生47个GDI句柄，只要Icon句柄释放，就不会再增长。现在还未找到处理多处理啊的调用所产生的这些GDI句柄。

 

注意：

  GHGetFileInfo 和 DestoryIcon 成对调用。

 

测试环境

   Win7 and XE2

 

 

View Code

unit Unit4;



interface



uses

  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;



type

  TForm4 = class(TForm)

    btn1: TButton;

    procedure btn1Click(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;



var

  Form4: TForm4;



implementation



uses

  ShellApi, Commctrl, ShlObj;



{$R *.dfm}





const

  SHIL_LARGE     = $00;  //The image size is normally 32x32 pixels. However, if the Use large icons option is selected from the Effects section of the Appearance tab in Display Properties, the image is 48x48 pixels.

  SHIL_SMALL     = $01;  //These images are the Shell standard small icon size of 16x16, but the size can be customized by the user.

  SHIL_EXTRALARGE= $02;  //These images are the Shell standard extra-large icon size. This is typically 48x48, but the size can be customized by the user.

  SHIL_SYSSMALL  = $03;  //These images are the size specified by GetSystemMetrics called with SM_CXSMICON and GetSystemMetrics called with SM_CYSMICON.

  SHIL_JUMBO     = $04;  //Windows Vista and later. The image is normally 256x256 pixels.

  IID_IImageList: TGUID= '{46EB5926-582E-4017-9FDF-E8998DAA0950}';



function GetImageListSH(SHIL_FLAG:Cardinal): HIMAGELIST;

type

  _SHGetImageList = function (iImageList: integer; const riid: TGUID; var ppv: Pointer): hResult; stdcall;

var

  Handle        : THandle;

  SHGetImageList: _SHGetImageList;

begin

  Result:= 0;

  Handle:= LoadLibrary('Shell32.dll');

  if Handle<> S_OK then

  try

    SHGetImageList:= GetProcAddress(Handle, PChar(727));

    if Assigned(SHGetImageList) and (Win32Platform = VER_PLATFORM_WIN32_NT) then

      SHGetImageList(SHIL_FLAG, IID_IImageList, Pointer(Result));

  finally

    FreeLibrary(Handle);

  end;

end;





procedure GetIconFromFile(aFile:String; var aIcon : TIcon;SHIL_FLAG:Cardinal);

var

  aImgList    : HIMAGELIST;

  SFI         : TSHFileInfo;

Begin

    //Get the index of the imagelist

    SHGetFileInfo(PChar(aFile), FILE_ATTRIBUTE_NORMAL, SFI,

                 SizeOf( TSHFileInfo ), SHGFI_ICON or SHGFI_LARGEICON or SHGFI_SHELLICONSIZE or

                 SHGFI_SYSICONINDEX or SHGFI_TYPENAME or SHGFI_DISPLAYNAME );



    if not Assigned(aIcon) then

    aIcon:= TIcon.Create;

    //get the imagelist

    aImgList:= GetImageListSH(SHIL_FLAG);

    //extract the icon handle

    aIcon.Handle:= ImageList_GetIcon(aImgList, Pred(ImageList_GetImageCount(aImgList)), ILD_NORMAL);



    DestroyIcon(SFI.hIcon);

    ImageList_Destroy(aImgList);

end;



procedure TForm4.btn1Click(Sender: TObject);

var

  icon:TIcon;

begin

  icon := TIcon.Create;

  try

    GetIconFromFile(ParamStr(0), icon, SHIL_JUMBO);

    canvas.Draw(10, 100, icon);

    Canvas.TextOut(10, 80, inttostr(icon.Handle));



    GetIconFromFile(ParamStr(0), icon, SHIL_SYSSMALL);

    canvas.Draw(10+ 280 , 100, icon);

    Canvas.TextOut(10 + 280, 80, inttostr(icon.Handle));



    GetIconFromFile(ParamStr(0), icon, SHIL_EXTRALARGE);

    canvas.Draw(10+ 280 + 150 , 100, icon);

    Canvas.TextOut(10+ 280 + 150, 80, inttostr(icon.Handle));



    GetIconFromFile(ParamStr(0), icon, SHIL_LARGE);

    canvas.Draw(10+ 280 + 150 +50 , 100, icon);

    Canvas.TextOut(10+ 280 + 150 +50, 80, inttostr(icon.Handle));



    GetIconFromFile(ParamStr(0), icon, SHIL_SMALL);

    canvas.Draw(10+ 280 + 150 +50 +40, 100, icon);

    Canvas.TextOut(10+ 280 + 150 +50 +40, 80, inttostr(icon.Handle));

  finally

    icon.Free;

  end;



end;



end.

 

详细内容可以看

http://www.codeproject.com/Articles/2532/Obtaining-and-managing-file-and-folder-icons-using

有比较详细的使用说明