Introduction This article shows the enumeration of child windows. The code is written in win 32 and can be understood with a prior knowledge of it. Although i have tried well to explain all the points as far as possible. Code: //HEADER FILES # include <windows.h> //IDENTIFIERS # define IDC_CHECKBOX1 100 ///<Identifier For 1st Check Box # define IDC_CHECKBOX2 101 ///<Identifier For 2nd Check Box # define IDC_CHECKBOX3 102 ///<Identifier For 3rd Check Box # define IDC_CHECKBOX4 103 ///<Identifier For 4th Check Box # define IDC_RADIO11 104 ///<Identifier For 1st Radio Button # define IDC_RADIO12 105 ///<Identifier For 2nd Radio Button # define IDC_RADIO13 106 ///<Identifier For 3rd Radio Button # define IDC_RADIO21 107 ///<Identifier For 1st Radio Button # define IDC_RADIO22 108 ///<Identifier For 2nd Radio Button # define IDC_RADIO23 109 ///<Identifier For 3rd Radio Button # define IDC_EDITBOX 110 ///<Identifier For Edit Control # define IDC_LISTBOX 111 ///<Identifier For List Box # define IDC_SUBMIT 112 ///<Identifier For Submit Button # define IDC_GROUP1 113 ///<Identifier For 1st Group # define IDC_GROUP2 114 ///<Identifier For 2nd Group # define IDC_GROUP3 115 ///<Identifier For 3rd Group # define IDC_RESET 116 ///<Identifier For Reset Button # define IDC_COMBOBOX 117 ///<Identifier For Reset Button # define ONE 1 ///<Macro Declaration. # define TWO 2 ///<Macro Declaration. # define THREE 3 ///<Macro Declaration. # define FOUR 4 ///<Macro Declaration. # define ZERO 0 ///<Macro Declaration. # define FIVE 5 ///<Macro Declaration. //Global Variables HANDLE ghInstance; ///< Contains the instance of the Application int gCheckonce=1; ///<used for the submit button to allow only one submission. int i; #include "res.h" /** *This function deals with first checking where a previous instance is present or not. *If there is no previous instance then it creates a windows class and then registers it to the register class. * * @return int The resulting number of bytes copied * * @note * <ul> * <li>this function is the main entry point of the program. * </ul> */ int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow ) { WNDCLASS wc; //contains the window class attributes that are registered by the RegisterClass function MSG uMsg; //structure contains message information from a thread's message queue HWND hWnd; //handle to window BOOL bRet; if( !hPrevInstance ){ wc.lpszClassName = "GenericAppClass"; //Name to identify the window class. wc.lpfnWndProc =MainWndProc; //Pointer to the window procedure for this window class wc.style = CS_OWNDC | CS_VREDRAW | CS_HREDRAW; //Specifies the class style(s) wc.hInstance = hInstance; wc.hIcon = LoadIcon( NULL, IDI_APPLICATION ); //returns the handle to an icon to be loaded on the window wc.hCursor = LoadCursor( NULL, IDC_ARROW ); //returns the handle to the cursor that has to be displayed wc.hbrBackground = (HBRUSH)( COLOR_WINDOW+11); //set the background color wc.lpszMenuName = NULL; //class have no default menu wc.cbClsExtra = 0; wc.cbWndExtra = 0; RegisterClass( &wc ); //this will register the class } ghInstance = hInstance; //CreateWindow will return the handle to a new window hWnd = CreateWindow( "GenericAppClass", //name of the window class "EXAMPLE OF TAB CONTROL", //window name WS_OVERLAPPEDWINDOW|WS_HSCROLL| WS_VSCROLL|WS_CLIPSIBLINGS, //specifies the window style 0, //set the horizontal position of the window 0, //set the vertical position of the window CW_USEDEFAULT, //set the width of the window CW_USEDEFAULT, //set the height of the window NULL, //contains valid pointer for child window NULL, //class menu is used hInstance, //Handle to the instance associated with the window NULL ); //function to show the window ShowWindow( hWnd, SW_MAXIMIZE ); //it will be executed if function will return nonzero value while( (bRet = GetMessage( &uMsg, NULL, 0, 0 )) != 0 ) //GetMessage retrieves messages for any window that belongs to the calling thread and thread messages posted to the calling thread using the PostThreadMessage function. { //execute if there is an error otherwise 'else' part is executed if (bRet == -1) { return 0; } else { TranslateMessage( &uMsg ); //translates virtual-key messages into character messages. DispatchMessage( &uMsg ); //dispatches a message to a window procedure } } //loops ended return (int)uMsg.wParam; // returns integer that indicates the additional information of the msg } // End of WinMain() /** * MainWndProc procedure * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] msg specifies the msg * * @return 0 returns zero. * */ LRESULT CALLBACK MainWndProc(HWND phWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { switch(uMsg ){ //call function to create all controls. case WM_CREATE: CreateControls(phWnd); ///<creates all the controls. //enumerates the child window proc. //The EnumChildWindows function enumerates the child windows that belong to the specified parent window by //passing the handle to each child window. //EnumChildProc receives the child window handles. //SubClassProc is used to intercept the messages meant for the default window into the controls window EnumChildWindows(phWnd,(WNDENUMPROC) EnumChildProc,(LONG)SubClassProc); break; //used to close the window case WM_CLOSE: if((MessageBox(phWnd, "DO YOU REALLY WANT TO EXIT ?", "Message",MB_OKCANCEL))==IDOK){ //for final exit DestroyWindow(phWnd); // POSTS THE MESSAGE WM_DESTROY TO DESTROY THE CREATED WINDOW. } break; case WM_COMMAND: //Handling Window Controllers switch(LOWORD(wParam)){ case IDC_SUBMIT: //handles the submission of the details into the list box on clicking submit if(HIWORD(wParam)==BN_CLICKED && gCheckonce==ONE){ // hiword(wParam) takes the notification AddItemsInListBox(phWnd); //displays all the details in the list box. gCheckonce=TWO; } break; case IDC_RESET: if(HIWORD(wParam)==BN_CLICKED){ for(i=ZERO; i<FOUR; i++){ //sends message to uncheck the radio buttons of the first group. SendMessage(GetDlgItem(phWnd,(IDC_RADIO11+i)),BM_SETCHECK,BST_UNCHECKED,0); //sends message to uncheck the radio buttons of the second group SendMessage(GetDlgItem(phWnd,(IDC_RADIO21+i)),BM_SETCHECK,BST_UNCHECKED,0); //sends message to uncheck the check boxes. SendMessage(GetDlgItem(phWnd,(IDC_CHECKBOX1+i)),BM_SETCHECK,BST_UNCHECKED,0); } //sends message to reset the edit box. SendMessage(GetDlgItem(phWnd,IDC_EDITBOX),WM_SETTEXT,0,(LPARAM)" "); //sends message to reset the combo box. SendMessage(GetDlgItem(phWnd,IDC_COMBOBOX),CB_SETCURSEL,0,0); //sends message to reset the list box. SendMessage(GetDlgItem(phWnd,IDC_LISTBOX),LB_RESETCONTENT,0,0); //resets the flag of the submit button to 1. gCheckonce=ONE; } break; } break; //USED TO CONTROL WINDOW case WM_DESTROY: PostQuitMessage(0); // posts the message wm_quit to quit the window. break; //TO PROVIDE DEFAULT PROCESSING ON ANY WINDOW MESSAGES default: return( DefWindowProc( phWnd, uMsg, wParam, lParam )); } return 0; } /** * CreateLabels() used to create labels for all the controls * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Parent Window * @param [in] hwndCheckBox contains the address of the check box control * */ void CreateLabels(HWND phWnd) { //LABEL FOR THE COMBO BOX CreateWindow("Static","Enter the field of Study:",WS_CHILD|WS_VISIBLE|SS_LEFT,40,80,200, 20,phWnd,NULL,ghInstance,NULL); //LABEL FOR THE BADIOBUTTONS OF FIRST GROUP CreateWindow("Static","Enter the Students Year Of Study:",WS_CHILD|WS_VISIBLE|SS_LEFT,40,160,250 ,20,phWnd,NULL,ghInstance,NULL); //LABEL FOR THE EDIT BOX CreateWindow("Static","Enter the Students Name:",WS_CHILD|WS_VISIBLE|SS_LEFT,510,80,180,20, phWnd,NULL,ghInstance,NULL); //LABEL FOR THE RADIOBUTTONS OF THE SECOND GROUP CreateWindow("Static","Enter the Students Initials:",WS_CHILD|WS_VISIBLE|SS_LEFT,510,160,180,20, phWnd,NULL,ghInstance,NULL); //LABEL FOR THE CHECK BOX CreateWindow("Static","Enter the Students Hobbies:",WS_CHILD|WS_VISIBLE|SS_LEFT,220,350,280,20, phWnd,NULL,ghInstance,NULL); } /** * CreateControls() used to create Controls for all the controls * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Parent Window * */ void CreateControls( HWND phWnd ) { //TO CREATE COMBO BOX CreateComboBox(phWnd); //TO CREATE RADIOBUTTON CreateRadioButtonfirstgroup(phWnd,180); //TO CREATE LABELS FOR ALL THE CONTROLS CreateLabels(phWnd); //TO CREATE THE GROUP STRUCTURE CreateGroups(phWnd); // CreateEditBox(phWnd); CreateEditBox(phWnd); //TO CREATE SECOND SET OF RADIOBUTTONS CreateRadioButtonsecondgroup(phWnd,180); //TO CREATE CHECK BOX CreateCheckBox(phWnd,340); //TO CREATE THE SUBMIT AND RESET BUTTONS FOR THE 1ST TAB Createopbutton(phWnd); //TO CREATE LIST BOX CONTROL CreateListBox(phWnd); //used to setfocus on ComboBox SetFocus(GetDlgItem(phWnd,IDC_COMBOBOX)); } /** * CreateGroups() used to create groups for all the controls * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Parent Window * @param [in] hwndCheckBox contains the address of the check box control * */ void CreateGroups(HWND phWnd) { //CREATES THE OUTLINE FOR THE FIRST GROUP CreateWindow("Button", "SUBJECT DETAILS" , WS_CHILD | WS_VISIBLE |BS_GROUPBOX,30,50,400,250,phWnd, (HMENU)IDC_GROUP1,ghInstance,NULL); //CREATES THE OUTLINE FOR THE SECOND GROUP CreateWindow("Button", "STUDENT DETAILS" , WS_CHILD | WS_VISIBLE |BS_GROUPBOX,500,50,400, 250,phWnd,(HMENU)IDC_GROUP2,ghInstance,NULL); //CREATES THE OUTLINE FOR THE THIRD GROUP CreateWindow("Button", "HOBBIES" , WS_CHILD | WS_VISIBLE |BS_GROUPBOX,30,320,670, 120,phWnd,(HMENU)IDC_GROUP3,ghInstance,NULL); } /** * CreateRadioButtonfirstgroup() used to create Radio Button for first Group Box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] button_no Contains the Radio button no. * */ void CreateRadioButtonfirstgroup(HWND phWnd,int y_axis) { int i,x_axis; char *radiobuttonnames[]={"I","II","III"}; for(i=ZERO,x_axis=50;i<THREE;i++,x_axis+=90){ CreateWindow("Button",radiobuttonnames[i],WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_AUTORADIOBUTTON, x_axis,y_axis,50,100,phWnd,(HMENU)(IDC_RADIO11+i),ghInstance,NULL); } } /** * CreateRadioButtonsecondgroup() used to create Radio Button for second Group Box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] button_no Contains the Radio button no. * */ void CreateRadioButtonsecondgroup(HWND hWnd,int y_axis) { int i,x_axis; char *radiobuttonnames1[]={"Mr","Miss","Mrs"}; for(i=ZERO,x_axis=520;i<THREE;i++,x_axis+=90){ CreateWindow("Button",radiobuttonnames1[i],WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_AUTORADIOBUTTON, x_axis,y_axis,50,100,hWnd,(HMENU)(IDC_RADIO21+i),ghInstance,NULL); } } /** * Createopbutton() used to create submit and reset button * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] button_no Contains the Radio button no. * */ void Createopbutton(HWND phWnd) { //CREATES THE SUBMIT BUTTON CreateWindow("Button","Submit",WS_CHILD|WS_VISIBLE|BS_DEFPUSHBUTTON|WS_TABSTOP ,350,600,100,30, phWnd,(HMENU)IDC_SUBMIT,ghInstance,NULL); //CREATES THE RESET BUTTON CreateWindow("Button","Reset",WS_CHILD|WS_VISIBLE|BS_DEFPUSHBUTTON|WS_TABSTOP ,550,600,100,30, phWnd,(HMENU)IDC_RESET,ghInstance,NULL); } /** * CreateCheckBox() creates the check boxes * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Parent Window * @param [in] hwndCheckBox contains the address of the check box control * */ void CreateCheckBox(HWND phWnd,int y_axis) { int x_axis,i; char *checkboxnames[]={"Singing","Dancing","Sketching","Drawing"}; for(i=ZERO,x_axis=50;i<FOUR;i++,x_axis+=150){ CreateWindow("Button",checkboxnames[i],WS_CHILD|WS_VISIBLE|BS_AUTOCHECKBOX|WS_TABSTOP, x_axis,390,100,15,phWnd,(HMENU)(IDC_CHECKBOX1+i),ghInstance,NULL); } } /** * CreateComboBox() used to create Combo Box For first Group Box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * */ void CreateComboBox(HWND phWnd) { char *comboitem[] = { "SELECT", "MATHS", "BIOLOGY", "COMMERCE", "ARTS" }; int i; CreateWindow( "COMBOBOX", "", CBS_DROPDOWNLIST | WS_CHILD | WS_VISIBLE |WS_TABSTOP|WS_GROUP, 70, 100, 200, 500, phWnd, (HMENU) IDC_COMBOBOX, ghInstance, NULL); //Add items in the Combo Box for(i=ZERO;i<FIVE;i++) SendMessage(GetDlgItem(phWnd,IDC_COMBOBOX), CB_ADDSTRING, 0, (LPARAM) comboitem[i]); } /** * CreateEditBox() used to create submit and reset button * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] button_no Contains the Radio button no. * */ void CreateEditBox(HWND phWnd) { //CREATES THE EDIT BOX CreateWindow("Edit",NULL,WS_CHILD|WS_VISIBLE |WS_BORDER|WS_GROUP|WS_TABSTOP,700,70,180,40, phWnd,(HMENU)IDC_EDITBOX, ghInstance,NULL); } /** * CreateListBox() used to create List Box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * */ void CreateListBox(HWND phWnd) { //CREATES THE LIST BOX CreateWindow("ListBox",NULL,WS_CHILD|WS_VISIBLE |WS_BORDER |WS_VSCROLL , 200,480,200,50,phWnd,(HMENU)IDC_LISTBOX,ghInstance,NULL); } /** * AddItemsToListBox() used to retrieve text from all the controls and add those in List Box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window */ void AddItemsInListBox(HWND phWnd) { //CALL FUNCTION TO RETRIEVE THE SELECTED STRING FROM THE COMBO BOX RetrieveTextFromComboBox(phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE CHECK BOX 1 SELECTD OR N0T checkbox(GetDlgItem(phWnd,IDC_CHECKBOX1),phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE CHECK BOX 2 IS SELECTD OR N0T checkbox(GetDlgItem(phWnd,IDC_CHECKBOX2),phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE CHECK BOX 3 IS SELECTD OR N0T checkbox(GetDlgItem(phWnd,IDC_CHECKBOX3),phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE CHECK BOX 3 IS SELECTD OR N0T checkbox(GetDlgItem(phWnd,IDC_CHECKBOX4),phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 1 OF RADIO GROUP 1 IS SELECTD OR N0T radiocheck(IDC_RADIO11,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 2 OF RADIO GROUP 1 IS SELECTD OR N0T radiocheck(IDC_RADIO12,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 3 OF RADIO GROUP 1 IS SELECTD OR N0T radiocheck(IDC_RADIO13,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 1 OF RADIO GROUP 2 IS SELECTD OR N0T radiocheck(IDC_RADIO21,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 2 OF RADIO GROUP 2 IS SELECTD OR N0T radiocheck(IDC_RADIO22,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE RADIO BUTTON 3 OF RADIO GROUP 2 IS SELECTD OR N0T radiocheck(IDC_RADIO23,phWnd); //CALL FUNCTION TO CHECK THAT WEATHER THE TEXT IS AVILABLE IN EDIT CONTROL OR N0T EditText(phWnd); } /** * radiocheck() used to check whether or not Radio Buttons are checked * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * @param [in] Button_no Identifier of Radio Button. * */ void radiocheck(int pButton_no,HWND phWnd) { char* edittext; int i; //RETURN TRUE IF RADIO BUTTON IS SELECTED if(SendMessage( GetDlgItem(phWnd,pButton_no),BM_GETCHECK,0,0) == BST_CHECKED) { //Retrieve the length of the text associated with the CheckBox i = GetWindowTextLength( GetDlgItem(phWnd,pButton_no)); //Allocate memory of i length edittext = (char*)malloc((i+1)*sizeof(char)); //Retrieve the string associated with the Radio Buttons GetWindowText( GetDlgItem(phWnd,pButton_no), edittext,i+1); //Add that string in to the List box SendMessage(GetDlgItem(phWnd,IDC_LISTBOX),LB_ADDSTRING,0,(LPARAM) edittext); free(edittext); } } /** * EditText() used to retrieve text from Edit Text control of first group box and add it to the list box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * */ void EditText(HWND phWnd) { char *edittext; ///<contains the address of the Buffer //call RetrieveText() to retrieve text from the Edit Control of First Group Box edittext=RetrieveText( GetDlgItem(phWnd,IDC_EDITBOX)); //add that string in the List box SendMessage(GetDlgItem(phWnd,IDC_LISTBOX),LB_ADDSTRING,0,(LPARAM) edittext); free(edittext); } /** * RetrieveTextFromComboBox() used to retrieve selected text from combo box * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * */ void RetrieveTextFromComboBox(HWND phWnd) { char *edittext; int CBIndex; (LRESULT) CBIndex = SendMessage(GetDlgItem(phWnd,IDC_COMBOBOX),CB_GETCURSEL,0,0); //checks whether or not any value is selected in the combo box if not retuns -1 if (CBIndex != -1) { edittext=RetrieveText( GetDlgItem(phWnd,IDC_COMBOBOX)); //ADD THE RETRIEVED TEXT TO THE LIST BOX SendMessage(GetDlgItem(phWnd,IDC_LISTBOX),LB_ADDSTRING,0,(LPARAM) edittext); free(edittext); } } /** * RetrieveText() used to retireve text from th edit control * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Window * */ char* RetrieveText(HWND phWnd) { char *edittext; int textlength; //Retrieve text length (LRESULT) textlength = SendMessage( phWnd,WM_GETTEXTLENGTH,0,0); edittext=(char*)calloc(textlength+1,sizeof(char)); //retrieve the string entered in the Edit Control SendMessage( phWnd,WM_GETTEXT,textlength+1,(LPARAM) edittext); return edittext; } /** * checkbox() used to check whether or not check boxes are checked * * This continues into the more detailed description of the function. * * @param [in] hWnd Contains the address of the Parent Window * @param [in] hwndCheckBox contains the address of the check box control * */ void checkbox(HWND phwndCheckBox , HWND phWnd) { char * edittext; int i; //RETURN TRUE IF CHECK BOX IS SELECTED if(SendMessage(phwndCheckBox,BM_GETCHECK,0,0)==BST_CHECKED) { //retrieve the length of the text associated with the CheckBox i = GetWindowTextLength(phwndCheckBox); //Allocate memory of i length edittext = (char*)malloc((i+1)*sizeof(char)); //retrieve the string associated with the CheckBox i = GetWindowText( phwndCheckBox, edittext,(i+1) ); //add that string in to the List box SendMessage(GetDlgItem( phWnd, IDC_LISTBOX ),LB_ADDSTRING,0,(LPARAM) edittext); free(edittext); } } /** *This function enumerates child procedure. * * @note * <ul> * <li>this function enumerates the procedures of all the controls in the order of their creation. * </ul> */ BOOL CALLBACK EnumChildProc(HWND handle,LPARAM lParam) { WNDPROC SubclassWndProc; SubclassWndProc=(WNDPROC) SetWindowLong(handle,GWL_WNDPROC,(LONG)lParam); /**The SetWindowLong function changes an attribute of the specified window. *GWL_USERDATA in this we are attaching the address of the previous window proc. */ SetWindowLong(handle,GWL_USERDATA,(LONG)SubclassWndProc); return TRUE; } /** *This function calls for the sub class procedure. * * @note * <ul> * <li>this function allows the user to move from one control to the another with the help of tab. * <li>this function allows the user to submit or reset the details entered with the help of tab. * </ul> */ LRESULT CALLBACK SubClassProc(HWND phWnd, UINT uMsg, WPARAM wParam, LPARAM lParam) { int id=GetDlgCtrlID(phWnd); switch(uMsg){ //this is used to handle keyboard events. case WM_CHAR: switch(wParam){ //this is used for the tab key event. case VK_TAB: SetFocus(GetNextDlgTabItem(GetParent(phWnd),phWnd,FALSE)); break; //this is used for the enter key event. case VK_RETURN: if(id==IDC_RESET||id==IDC_SUBMIT){ SendMessage(phWnd,BM_CLICK,0,0); } break; } break; } return CallWindowProc((WNDPROC)GetWindowLong(phWnd,GWL_USERDATA),phWnd,uMsg,wParam,lParam); }
hi please try to understand the code ,every line has a comment, even after that if you have a problem please feel free to ask me i will help you line by line
see when we create controls and want to enumerate it as a child proc, what we do is that we retrieve the handle of the controls one after the other in the order of their creation and pass it back to the window procedure that needed it . this enumeration helps us to call all the keep a single or same procedure for all the controls , by enumerating their handles
see the order of creation is the order in which you create the controls. system has nothing to do with the creation order. if you write code to create Radio Button 1 ,then edit box, then RadioButton 2, they will be creted in the same order.
see in my code go through the create controls function . in that i have created combo box first,then radiobuttons..................... what ever is the order of creation ,same is the order of enumeration.
