Win32 Tips

Some C++ Tips and Functions

2011-05-13T12:59:00.000-07:00

A simple C++ function to tokenize a string

#include <vector>
#include <string>
#include <sstream>
using namespace std;
vector<string>  getTokens(string str){
 string buf;  // Have a buffer string
 stringstream ss(str);  // Insert the string into a stream
 vector tokens;  // Create vector to hold our words
 while (ss >> buf)
    tokens.push_back(buf);
 return tokens;
}

A more complex tokenize function

void Tokenize(const string& str,
                      vector& tokens,
                      const string& delimiters = " ")
{
     // Skip delimiters at beginning.
    string::size_type lastPos = str.find_first_not_of(delimiters, 0);
     // Find first "non-delimiter".
    string::size_type pos     = str.find_first_of(delimiters, lastPos);
    while (string::npos != pos || string::npos != lastPos)
    {
         // Found a token, add it to the vector.
        tokens.push_back(str.substr(lastPos, pos - lastPos));
         // Skip delimiters.  Note the "not_of"
        lastPos = str.find_first_not_of(delimiters, pos);
         // Find next "non-delimiter"
        pos = str.find_first_of(delimiters, lastPos);
    }
}

Usage:

 vector<string> tokens;
  string str("Split,me up!Word2 Word3.");
  Tokenize(str, tokens, ",<'> " );
  vector <string>::iterator iter;
  for(iter = tokens.begin();iter!=tokens.end();iter++){
    cout<< (*iter) << endl;
 }

Write a number to a string

int                   myInteger;
string              myString;
ostringstream myStream;
 // Copy Integer to String Stream
myStream << myInteger;
 // Assign characters in stream to std::string
myString = myStream.str();

A stream can be cleared in the following way:

myStream.str("");

Replace a vector element

vector  theVector;
 //populate the vector
theVector.at(2) = "new string";

Transform HTML color code string to COLORREF

The string parameter is assumed to be in '#FFFFFF' format.

COLORREF transformHTML(string color){
 string s1(color, 1,2);
 string s2(color, 3,2);
 string s3(color, 5,2);

 long r = strtol(s1.c_str(), NULL, 16);
 long g = strtol(s2.c_str(), NULL, 16);
 long b = strtol(s3.c_str(), NULL, 16);

 return RGB (r,g,b);
}

Determine Whether A String is in Upper Case

bool isUpper(string line){
 const char *str = line.c_str();
 while(*str != '\0'){
  if(IsCharLower(*str))
   return false;
  *str++;
 }
 return true;
}
A Windows IsCharLower function is used.

Convert str::string to char

Use the c_str() function.

Example:

string str = "test string";
const char *ch = str.c_str();

Pass string arrays to functions

This actually refers to C.
You declare a string array in the calling function as follows:

 char arr[10][30];

The second dimension must always have the exact number of elements in the function declaration:

 int functionName(char  (*arr) [30], int numberOfElements 10);

The brackets around the array name are important. You also passthe number of elements in the first dimension as an argument to the function.

Make Sure Only One Instance of the Application Is Running

2009-03-25T10:01:00.000-07:00

Place the following code in your WinMain:


// Look for the running instance of the application
char* szTitle = "My Title";
if (FindWindow(NULL, szTitle)){
  SetForegroundWindow(FindWindow(NULL, szTitle));
  return FALSE;
}

First, it looks for a window that has the same title as your application. If it finds it, it will make it active.
Another approach is to use a mutex:


BOOL IsFirstInstance()
{
HANDLE hMutex = CreateMutex(NULL, FALSE, "PUT A GUID HERE");
if(hMutex && GetLastError() == ERROR_ALREADY_EXISTS)
{
ReleaseMutex(hMutex);
return FALSE;
}
ReleaseMutex(hMutex);
return TRUE;
}

You call the above-mentioned function in your "InitInstance" method of your application.

How to Launch Internet Properties Control Applet

2009-03-25T10:00:00.001-07:00

Use the following code:


WinExec("rundll32 inetcpl.cpl LaunchConnectionDialog", SW_SHOW);

Measure Time In Milliseconds

2009-03-25T09:58:00.001-07:00

Use the DWORD GetTickCount(void) function.
The return value is the number of milliseconds that have elapsed since the system was started.
Example Code:


DWORD dwStart = GetTickCount();

Stop if this has taken too long:


if( GetTickCount() - dwStart >= TIMELIMIT )
Cancel();

Measure Time In Milliseconds

2009-03-25T09:58:00.000-07:00

Use the DWORD GetTickCount(void); function.

The return value is the number of milliseconds that have elapsed since the system was started.

Example Code:

DWORD dwStart = GetTickCount();

Stop if this has taken too long:

if( GetTickCount() - dwStart >= TIMELIMIT )

Cancel();

Retrieve Menu Item Text with GetMenuItemInfo function

2009-03-25T09:57:00.000-07:00


MENUITEMINFO MenuItem;
HMENU hmenu, hsubmenu;
HWND hwnd; //handle to main window
char szString[256];
int countLast =0;
//Initialize MENUITEMINFO structure:
memset(&MenuItem,0, sizeof(MenuItem));
MenuItem.cbSize = sizeof(MenuItem);
MenuItem.fMask =MIIM_TYPE; 
MenuItem.fType = MFT_STRING;
//Important - the dwTypeData and cch data members must also be initialized to receive the string.
MenuItem.cch = 256; 
MenuItem.dwTypeData = szString;
hmenu = GetMenu(hwnd); //get the menu
hsubmenu = GetSubMenu(hmenu,0); //get the first submenu

countLast = GetMenuItemCount(hsubmenu); //count number of items in the submenu; starts with 0;

GetMenuItemInfo(hsubmenu, 0, --countLast, &MenuItem );

MessageBox(NULL, MenuItem.dwTypeData, "Last Menu Item", MB_OK);

Use Bold or Underlined Font

2009-03-25T09:55:00.000-07:00

1. Define a static HFONT variable:

static HFONT hFont;

2. In the response to the WM_INITDIALOG message, create a font with desired features, using CreateFont function:


HFONT CreateFont(
int nHeight, // logical height of font 
int nWidth, // logical average character width 
int nEscapement, // angle of escapement 
int nOrientation, // base-line orientation angle 
int fnWeight, // font weight 
DWORD fdwItalic, // italic attribute flag 
DWORD fdwUnderline, // underline attribute flag 
DWORD fdwStrikeOut, // strikeout attribute flag 
DWORD fdwCharSet, // character set identifier 
DWORD fdwOutputPrecision, // output precision 
DWORD fdwClipPrecision, // clipping precision 
DWORD fdwQuality, // output quality 
DWORD fdwPitchAndFamily, // pitch and family 
LPCTSTR lpszFace // pointer to typeface name string 
);

Use the pre-defined FW_BOLD parameter for fnWeight for Bold text.
Set fdwUnderline parameter to TRUE for underlined text.

Use default values for most of the other parameters.

Here is a simple helper function:


HFONT SimpleCreateFont( int Height, BOOL Bold, BOOL Italic, BOOL Underline,
BOOL StrikeOut, DWORD Family, char* FaceName )
{
HFONT Ret;
int Weight;
Weight = Bold ? FW_BOLD : FW_NORMAL;
Ret = CreateFont( Height, 0, 0, 0, Weight,
Italic, Underline, StrikeOut, DEFAULT_CHARSET, OUT_DEFAULT_PRECIS,
CLIP_DEFAULT_PRECIS, DEFAULT_QUALITY, DEFAULT_PITCH | Family, FaceName );
return( Ret );
}

3. Use the WM_SETFONT message to tell child control to use new font


SendMessage( GetDlgItem( hwnd, ID_WEB ), WM_SETFONT, (WPARAM)hFont, 0 );

Enable a Button Depending On Whether There is Any Text in the Edit Box

2009-03-25T08:58:00.000-07:00

Use this function:


int EntryFieldMessages(HWND hDlg,WPARAM wParam) { 
char buffer[1024]; 
//Get a handle to the button
HWND hIdOk = GetDlgItem(hDlg,1005);
switch (HIWORD(wParam)) {
case EN_CHANGE:
if (GetDlgItemText(hDlg,1004,
buffer, sizeof(buffer))) {
// There is some text in the entry field. Enable the IDOK button. 
EnableWindow(hIdOk,1);
}
else // no text, disable the IDOK button
EnableWindow(hIdOk,0);
break;
}
return 1;
}

in response to WM_COMMAND message, i.e.:


case 1004:
{
switch (HIWORD(wParam)){
case EN_CHANGE:
return EntryFieldMessages(hwnd,wParam);
}
break;
}

1004 represents an edit box identifier, of course.

Set Foreground Color to an Individual Edit Box or Static Control

2009-03-25T08:56:00.002-07:00

If you have several edit boxes but want to set color to one of them only,
capture the WM_CTLCOLOREDIT message and get the handle to that edit box.


case WM_CTLCOLOREDIT: 
//Get Handle to that control first

if((HWND)lParam==GetDlgItem(hwnd,IDC_TEXTBOX)){
HDC hDC = (HDC)wParam;
COLORREF color = RGB(192,0,0); // red color
SetTextColor(hDC, color);
//Optionally, set background color 
//SetBkColor(hDC, RGB(255,255,0)); /* yellow */
}
return GetStockObject(WHITE_BRUSH);
break;

For a static control use WM_CTLCOLORSTATIC message:
Example:


HDC hdcStatic = (HDC)wParam;
SetTextColor(hdcStatic, RGB(255, 0, 0)); //red color

Set the background mode to transparent to use the parent window's background color and return NULL_BRUSH:


SetBkMode(hdcStatic,TRANSPARENT); 
return GetStockObject(NULL_BRUSH);

A more detailed explanation at http://www.geocities.com/Heartland/Meadows/9818/win32tut/lesson4.html

How to Get a Handle to a Control

2009-03-25T08:56:00.001-07:00

Use GetDlgItem function:


 HWND GetDlgItem(
 HWND hDlg,       // handle of dialog box
 int nIDDlgItem   // identifier of control
 );

Create A Combo Box on a Toolbar

2009-03-25T07:37:00.000-07:00

const int nDropHeight = 100;

Create a dummy button on a toolbar. Separator style recommended.

Command identifier associated with the button:

button.idCommand = CM_DUMMY;

Get the button size:


RECT rect; 
SendMessage(g_hToolBar, TB_GETITEMRECT, 8, (LPARAM)&rect);
rect.top = 1;
rect.bottom = rect.top + nDropHeight;

Create a combo box window:


HWND hCombo = CreateWindowEx(0, szComboBox, NULL,
WS_CHILD|WS_VISIBLE|CBS_DROPDOWNLIST|CBS_HASSTRINGS|CBS_AUTOHSCROLL,
rect.left, rect.top, 100,50,
hwndToolBar, (HMENU)1100, hInst, NULL);

if(hCombo == NULL)
{
MessageBox(0, "Combo Creation Failed!", "Error!",

MB_ICONEXCLAMATION | MB_OK | MB_SYSTEMMODAL);
}

Create Toolbar Tips

2009-03-25T07:33:00.000-07:00

Declare:
LPNMTTDISPINFO TTtext;
Example:


 case WM_NOTIFY:
  TTtext = (LPNMTTDISPINFO)lParam;
  if(TTtext->hdr.code==TTN_GETDISPINFO)
   switch(TTtext->hdr.idFrom){
   case CM_RED_CIRCLE:
    TTtext->lpszText = "Red Circle";
    break;

   case CM_GREEN_SQUARE:
    TTtext->lpszText = "Green Square";
    break;
   case CM_BLUE_CIRCLE:
    TTtext->lpszText = "Blue Circle";
    break;

   case CM_YELLOW_SQUARE:
    TTtext->lpszText = "Yellow Square";
    break;

   }
     break;

How to Trap Enter key on Edit Box

2009-03-24T17:21:00.000-07:00

In order to trap the keypress you'll need to subclass the edit window.
Here's how to do it.
First, you'll need to store the original window proc in a global, so declare it as such:
FAR PROC DefEditProc;

Then you'll need to create a window proc to trap the message. Here's one that will do what you need:


LRESULT CALLBACK MyEditProc(HWND hDlg, UINT message,
  WPARAM wParam, LPARAM lParam) {
    switch(message) {
         case WM_CHAR:
              if( wParam == 13 ) {
      /* User pressed ENTER -- do what you want here. */
                   return(0);
              }
              else return( (LRESULT)CallWindowProc
                ((WNDPROC)DefEditProc,hDlg,message,wParam,lParam) );
         break;
         default:
               return( (LRESULT)CallWindowProc((WNDPROC)DefEditProc,
                 hDlg,message,wParam,lParam) );
         break;
    }
    return(0);
}

Everything else below should occur when you're initializing the window containing the edit box:

Store the Edit window handle into EditWnd. You can do this several ways...if you created the edit window in a dialog box you can do this:
HWND EditWnd = GetDlgItem(hDlg,IDC_EDIT1);

Otherwise you should already have a handle to the edit window -- just store it in EditWnd. Then do the actual subclassing:

DefEditProc = (WNDPROC)GetWindowLong(EditWnd,GWL_WNDPROC);
SetWindowLong(EditWnd,GWL_WNDPROC,(long)MyEditProc);

Display Last Error

2009-03-24T17:20:00.000-07:00


LPVOID lpMsgBuf;
if(SomeHandle==NULL){
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf,
0,
NULL
);
// Display the string.
MessageBox( NULL, lpMsgBuf, "GetLastError", MB_OK|MB_ICONINFORMATION );
// Free the buffer.
LocalFree( lpMsgBuf );
}

Attach Menu to Dialog-based Application

2009-03-24T17:18:00.001-07:00

1. Create menu resource MYMENU.
2. Use the following code in response to the WM_INITDIALOG message


HMENU hMenu = LoadMenu(hInst, MAKEINTRESOURCE(MYMENU));
SetMenu( hwnd,hMenu);

Retrieving the Path of the Running Application

2009-03-24T17:17:00.000-07:00


int GetAppPath(LPTSTR pstr,int length){
int ret,i;
// this gets the name of the running app
ret=GetModuleHandle(NULL,pstr,length);
if(!ret)return 0;
i=lstrlen(pstr)-1;
for(;i>=0;i--){
// replace backslash with a terminating null
 if(pstr[i]==TEXT('\\')){
  pstr[i]=TEXT('\0');
  break;
 }
}
return lstrlen(pstr); //return the length of the final string
}

Attach Icon to the Title bar of Dialog-based Application

2009-03-24T17:01:00.000-07:00


HICON hIcon = LoadIcon (hInst, MAKEINTRESOURCE (DLG_ICON));
SendMessage (hwnd, WM_SETICON, (WPARAM) ICON_SMALL, (LPARAM) hIcon);