sdk/samples/all in on code/Visual Studio 2008/ATLShellExtIconOverlayHandler/FileIconOverlayExt.cpp

   1 /****************************** Module Header ******************************\
   2 * Module Name:  FileIconOverlayExt.cpp
   3 * Project:      ATLShellExtIconOverlayHandler
   4 * Copyright (c) Microsoft Corporation.
   5 *
   6 * Icon overlays are small images placed at the lower-left corner of the icon
   7 * that represents a Shell object. They are normally added to an object's icon
   8 * to provide some extra information. For instance, a commonly used icon
   9 * overlay is the small arrow that indicates that the icon represents a link,
  10 * rather than the actual file or folder. In addition to the standard icon
  11 * overlays that are provided by the system, you can request custom icon
  12 * overlays for specified Shell objects by implementing and registering an
  13 * icon overlay handler.
  14 *
  15 * FileIconOverlayExt in ATLShellExtIconOverlayHandler demonstrates a shell
  16 * icon overlay handler for files with "Sample" in the file paths. After
  17 * installing the icon overlay handler, any file with "Sample" in its file
  18 * path, e.g. "D:\Sample.txt", shows an icon overlay in Windows Explorer.
  19 *
  20 * This source is subject to the Microsoft Public License.
  21 * See http://www.microsoft.com/opensource/licenses.mspx#Ms-PL.
  22 * All other rights reserved.
  23 *
  24 * THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND,
  25 * EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED
  26 * WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR PURPOSE.
  27 \***************************************************************************/
  28
  29 #pragma region Includes
  30 #include "stdafx.h"
  31 #include "FileIconOverlayExt.h"
  32 #pragma endregion
  33
  34
  35 /////////////////////////////////////////////////////////////////////////////
  36 // CFileIconOverlayExt IShellIconOverlayIdentifier methods.
  37 //
  38
  39 //
  40 //   FUNCTION: CFileIconOverlayExt::GetOverlayInfo(LPWSTR, int, int*, DWORD*)
  41 //
  42 //   PURPOSE: Provides the location of the icon overlay's bitmap. This method
  43 //            is first called during initialization, it returns the fully
  44 //            qualified path of the file containing the icon overlay image,
  45 //            and its zero-based index within the file. The icon can be
  46 //            contained in any of the standard file types, including .exe,
  47 //            .dll, and .ico. After initialization is complete, the Shell
  48 //            calls GetOverlayInfo when it needs to display the handler's
  49 //            icon overlay. The method should return the same file name and
  50 //            index that it did during initialization. Although the Shell
  51 //            uses the image that is cached in the system image list rather
  52 //            than loading the image from the file, an icon overlay is still
  53 //            identified by its file name and index.
  54 //
  55 IFACEMETHODIMP CFileIconOverlayExt::GetOverlayInfo(
  56         LPWSTR pwszIconFile, int cchMax, int* pIndex, DWORD* pdwFlags)
  57 {
  58         // Get the module's full path
  59         GetModuleFileNameW(_AtlBaseModule.GetModuleInstance(), pwszIconFile,
  60                 cchMax);
  61
  62         // Use the first icon in the resource
  63         *pIndex = 0;
  64
  65         *pdwFlags = ISIOI_ICONFILE | ISIOI_ICONINDEX;
  66
  67         return S_OK;
  68 }
  69
  70
  71 //
  72 //   FUNCTION: CFileIconOverlayExt::GetPriority(int*)
  73 //
  74 //   PURPOSE: Specifies the priority of an icon overlay. This method is
  75 //            called only during initialization. It assigns a priority value
  76 //            to the handler's icon overlay. The value can range from zero to
  77 //            100, where 100 is the lowest priority. The purpose of this
  78 //            priority value is to help the Shell resolve the conflict that
  79 //            arises when multiple icon overlays are specified for a single
  80 //            object. The Shell first uses an internal set of rules to
  81 //            determine the highest priority icon overlay. If these rules do
  82 //            not resolve the conflict, the values assigned to the icon
  83 //            overlays by GetPriority determine priority. The priority value
  84 //            set by GetPriority is not a reliable way to resolve conflicts
  85 //            between unrelated icon overlay handlers. There is no way for
  86 //            your handler to determine what priority values other handlers
  87 //            are using. Normally, you should set the value to zero. However,
  88 //            the priority value is useful when you have implemented two or
  89 //            more icon overlay handlers that can request icon overlay icons
  90 //            for the same object. By setting the priority values
  91 //            appropriately, you can specify which of the requested icon
  92 //            overlays will be displayed.
  93 //
  94 IFACEMETHODIMP CFileIconOverlayExt::GetPriority(int* pPriority)
  95 {
  96         // Request the highest priority
  97         *pPriority = 0;
  98
  99         return S_OK;
 100 }
 101
 102
 103 //
 104 //   FUNCTION: CFileIconOverlayExt::IsMemberOf(LPCWSTR, DWORD)
 105 //
 106 //   PURPOSE: Specifies whether an icon overlay should be added to a Shell
 107 //            object's icon or not. The Shell calls this method to determine
 108 //            whether it should display a handler's icon overlay for a
 109 //            particular object. It specifies the object by passing its name
 110 //            to the method. If a handler wants to have its icon overlay
 111 //            displayed, IsMemberOf returns S_OK. If not, it returns S_FALSE.
 112 //            Icon overlay handlers are normally intended to work with a
 113 //            particular group of files. A typical example is a file class,
 114 //            identified by a specific file name extension. An icon overlay
 115 //            handler can request an icon overlay for all members of the file
 116 //            class. Some handlers request an icon overlay only if a member
 117 //            of the file class is in a particular state. However, icon
 118 //            overlay handlers are free to request their icon overlay for any
 119 //            object that they want.
 120 //
 121 IFACEMETHODIMP CFileIconOverlayExt::IsMemberOf(LPCWSTR pwszPath,
 122                                                                                            DWORD dwAttrib)
 123 {
 124         // If the file name contains "Sample", add the overlay
 125         if (wcsstr(pwszPath, L"Sample") != 0)
 126                 return S_OK;
 127         else
 128                 return S_FALSE;
 129 }