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<HTML><LINK HREF="style.css" REL="STYLESHEET" TYPE="text/css"><HEAD><TITLE>Tutorial: Menus and Icons</TITLE></HEAD><BODY><FONT SIZE="-1">[ <A HREF="./index.html">contents</A>| <A HREF="http://www.winprog.org/">#winprog</A>]</FONT><HR><H1>Menus and Icons</H1><P>Example: menu_one</P><IMG SRC="images/menu_one.gif" ALT="[images/menu_one.gif]" ALIGN="right"><P>This is just a small section to show how to add basic menus to your window.Usually you use a pre-made menu resource. This will be in an .rc fileand will be compiled and linked into your .exe. This is rather compilerspecific, commercial compilers will have a resource editor that you can useto create your menus, but for this example I will show the text of the .rcfile so you can add it in manually. I usually have an .h file as well whichis included in both my .rc file and my .c source files. This file containsthe identifiers for controls and menu items etc.<P>For this example you can start with the window code from simple_window and add thiscode into it as instructed.<P>First the .h file. Usually called "resource.h"<PRE CLASS="LIST">#define IDR_MYMENU 101#define IDI_MYICON 201#define ID_FILE_EXIT 9001#define ID_STUFF_GO 9002</PRE>Not much there, but our menu will be pretty simple. The names and values hereare up to you for the choosing. Now we write our .rc file.<PRE CLASS="LIST">#include "resource.h"IDR_MYMENU MENUBEGIN POPUP "&File" BEGIN MENUITEM "E&xit", ID_FILE_EXIT END POPUP "&Stuff" BEGIN MENUITEM "&Go", ID_STUFF_GO MENUITEM "G&o somewhere else", 0, GRAYED ENDENDIDI_MYICON ICON "menu_one.ico"</PRE><P>You will want to add the .rc file to your project or makefile depending on what toolsyou are using.<P>You also want to <CODE>#include "resource.h"</CODE> in your source file (.c) so thatthe menu command identifiers and the menu resource id will be defined.<P>The easiest way to attach the menu and icon to your window is to specify them when youregister the window class, like this:<PRE CLASS="SNIP"> wc.lpszMenuName = MAKEINTRESOURCE(IDR_MYMENU);</PRE><PRE CLASS="SNIP"> wc.hIcon = LoadIcon(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON)); wc.hIconSm = (HICON)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(IDI_MYICON), IMAGE_ICON, 16, 16, 0);</PRE><P>Change that and see what happens. Your window should now have a File and Stuffmenu with the respective items underneath. That is assuming your .rc file wasproperly compiled and linked into your program. (again, see compiler notes)<P>The icon in the top left of the window and on the task bar should now display the small custom icon thatwe specified. If you hit Alt-Tab, the large version of the icon should be displayedin the application list.<P>I've used <CODE>LoadIcon()</CODE> to load the large icon because it's simpler, however it will onlyload icons at the default resolution of 32x32, so in order to load the smaller image, we need to use<CODE>LoadImage()</CODE>. Be aware that icon files and resources can contain multiple images, and inthis case the ones I've supplied contain the two sizes that I'm loading.<P>Example: menu_two</P><P> An alternative to using a menu resource is to create one on the fly (or when yourprogram runs). This is a bit more work programming wise, but adds flexibility andis sometimes necessary.<P>You can also use icons that aren't stored as resources, you could choose to store youricon as a seperate file and load it at runtime. This would also give you the option ofallowing the user to select an icon of their choice with the common dialogs discussed later,or something to that effect.<P>Start again from simple_window without the .h or .rc added. Now we willhandle the <CODE>WM_CREATE</CODE> message and add a menu to our window.<PRE CLASS="SNIP">#define ID_FILE_EXIT 9001#define ID_STUFF_GO 9002</PRE>Put these two id's at the top of your .c file this time, underneath your <CODE>#include</CODE>s.Next we add the following code into our <CODE>WM_CREATE</CODE> handler.<PRE CLASS="SNIP"> case WM_CREATE: { HMENU hMenu, hSubMenu; HICON hIcon, hIconSm; hMenu = CreateMenu(); hSubMenu = CreatePopupMenu(); AppendMenu(hSubMenu, MF_STRING, ID_FILE_EXIT, "E&xit"); AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&File"); hSubMenu = CreatePopupMenu(); AppendMenu(hSubMenu, MF_STRING, ID_STUFF_GO, "&Go"); AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Stuff"); SetMenu(hwnd, hMenu); hIcon = LoadImage(NULL, "menu_two.ico", IMAGE_ICON, 32, 32, LR_LOADFROMFILE); if(hIcon) SendMessage(hwnd, WM_SETICON, ICON_BIG, (LPARAM)hIcon); else MessageBox(hwnd, "Could not load large icon!", "Error", MB_OK | MB_ICONERROR); hIconSm = LoadImage(NULL, "menu_two.ico", IMAGE_ICON, 16, 16, LR_LOADFROMFILE); if(hIconSm) SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)hIconSm); else MessageBox(hwnd, "Could not load small icon!", "Error", MB_OK | MB_ICONERROR); } break;</PRE><P>This creates a menu almost the same as the one we had in the resource andattaches it to our window. A menu that is assigned to a window is automaticallyremoved when the program terminates, so we don't need to worry about getting ridof it later. If we did though, we could use <CODE>GetMenu()</CODE> and <CODE>DestroyMenu()</CODE>.<P>The code for the icons is pretty simple, we call <CODE>LoadImage()</CODE> twice, to load theicon as both a 16x16 size and a 32x32 size. We can't use <CODE>LoadIcon()</CODE> at allbecause it will only load resources, not files. We specify <CODE>NULL</CODE> for the instancehandle parameter because we aren't loading a resource from our module, and instead of a resourceID we pass in the name of the icon file we want to load. Finally, we pass in the <CODE>LR_LOADFROMFILE</CODE> flag to indicate that we want the function to treat the string we give itas a filename and not a resource name.<P>If each call succeeds we assign the icon handle to our window with <CODE>WM_SETICON</CODE>, and if itfails we pop up a message box letting us know something went wrong.<P><B>NOTE:</B> that the <CODE>LoadImage()</CODE> calls will fail if the icon file isn't in the currentworking directory of the program. If you are using VC++ and you run the program from the IDE, the currentworking directory will be the one the project file is in. However if you run the program from the Debug orRelease directories from explorer or the command shell, then you'll need to copy the icon file into that directoryin order for the program to find it. If all else fails, specify the full path to the icon, <CODE>"C:\\Path\\To\\Icon.ico"</CODE>.<P>Okay now that we have our menu, we need to make it do something. This ispretty simple, all we need to do is handle the <CODE>WM_COMMAND</CODE> message. Also we'll need to check which command we are getting and act accordingly. Now our<CODE>WndProc()</CODE> should look something like this.<PRE CLASS="SNIP">LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam){ switch(Message) { case WM_CREATE: { HMENU hMenu, hSubMenu; hMenu = CreateMenu(); hSubMenu = CreatePopupMenu(); AppendMenu(hSubMenu, MF_STRING, ID_FILE_EXIT, "E&xit"); AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&File"); hSubMenu = CreatePopupMenu(); AppendMenu(hSubMenu, MF_STRING, ID_STUFF_GO, "&Go"); AppendMenu(hMenu, MF_STRING | MF_POPUP, (UINT)hSubMenu, "&Stuff"); SetMenu(hwnd, hMenu); hIcon = LoadImage(NULL, "menu_two.ico", IMAGE_ICON, 32, 32, LR_LOADFROMFILE); if(hIcon) SendMessage(hwnd, WM_SETICON, ICON_BIG, (LPARAM)hIcon); else MessageBox(hwnd, "Could not load large icon!", "Error", MB_OK | MB_ICONERROR); hIconSm = LoadImage(NULL, "menu_two.ico", IMAGE_ICON, 16, 16, LR_LOADFROMFILE); if(hIconSm) SendMessage(hwnd, WM_SETICON, ICON_SMALL, (LPARAM)hIconSm); else MessageBox(hwnd, "Could not load small icon!", "Error", MB_OK | MB_ICONERROR); } break; case WM_COMMAND: switch(LOWORD(wParam)) { case ID_FILE_EXIT: break; case ID_STUFF_GO: break; } break; case WM_CLOSE: DestroyWindow(hwnd); break; case WM_DESTROY: PostQuitMessage(0); break; default: return DefWindowProc(hwnd, Message, wParam, lParam); } return 0;}</PRE>As you can see we've got our <CODE>WM_COMMAND</CODE> all set up, and it even has another <CODE>switch()</CODE> in it.This <CODE>switch()</CODE>'s on the value of the low word of <CODE>wParam</CODE>, which in the case of <CODE>WM_COMMAND</CODE>contains the control or menu id that sent the message.<P>We obviously want the Exit menu item to close the program. So in the <CODE>WM_COMMAND</CODE>,<CODE>ID_FILE_EXIT</CODE> handler you can use the following code to do just that.<PRE CLASS="SNIP">PostMessage(hwnd, WM_CLOSE, 0, 0);</PRE><P>Your WM_COMMAND handler should now look like this:<PRE CLASS="SNIP"> case WM_COMMAND: switch(LOWORD(wParam)) { case ID_FILE_EXIT: PostMessage(hwnd, WM_CLOSE, 0, 0); break; case ID_STUFF_GO: break; } break;</PRE>I leave it up to you to make the other menu command <CODE>ID_STUFF_GO</CODE> do something.<H3>The program file icon</H3>You may have noticed that the <CODE>menu_one.exe</CODE> file now shows up as the custom icon we added as a resource, whereas the <CODE>menu_two.exe</CODE> file does not, since we are loading an external file. WindowsExplorer simply displays the first icon (numerically by ID) in the program files resources, so since we only have one icon, that's what it is displaying. If you want to be sure that a certainicon is displayed with your program file, simply add it as a resource and assign it a very low ID... like <CODE>1</CODE>.You don't even need to refer to the file in your program, and you can load completely different icons foryour windows if you choose.<HR><FONT SIZE="-1">Copyright © 1998-2003, Brook Miles (<A HREF="mailto:forger(nospam)winprog.org">theForger</A>). All rights reserved.</FONT><SCRIPT language="JavaScript"><!-- var re = /\(nospam\)/ig; var str; for(i = 0;i < document.links.length;i++) { str = "" + document.links(i).href; if(str.search(re) != -1) document.links(i).href = str.replace(re, "@"); str = "" + document.links(i).innerHTML; if(str.search(re) != -1) document.links(i).innerHTML = str.replace(re, "@"); }--></SCRIPT></BODY></HTML>?? 快捷鍵說明
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