Introduction
The following are some tricks and tips that I have explored across my projects. Just I want to share it with you all. May be you are all well known about something or all things in this article. But, just I am looking for beginners to take advantage of this article.
Drag & Drop option for your application
- Add
WS_EX_ACCEPTFILES
style to your application’s extended styles.
- Add
WM_DROPFILES
message handler to your application.
void CYourDialog::OnDropFiles(HDROP hDropInfo)
{
CString sFile;
char *s=sFile.GetBufferSetLength(255);
int numFiles=DragQueryFile(hDropInfo,0xFFFFFFFF,s,255);
sFile.ReleaseBuffer();
for(int i=0;i<numFiles;i++)
{
s=sFile.GetBufferSetLength(255);
DragQueryFile(hDropInfo,i,s,255);
sFile.ReleaseBuffer();
MessageBox(sFile);
}
CDialog::OnDropFiles(hDropInfo);
}
Limiting MFC application to one instance
Put the following code in OnInitInstance()
.
BOOL bFound=FALSE;
HANDLE hMutexOneInstance = CreateMutex(NULL,TRUE,_T("UniqueInstanceName"));
if(GetLastError() == ERROR_ALREADY_EXISTS)
bFound = TRUE;
if(hMutexOneInstance)
ReleaseMutex(hMutexOneInstance);
if(bFound) return FALSE;
Getting the IP Address
Include the Winsock header file.
#include <WinSock.h>
Include the wsock32 library.
#pragma comment(lib,"wsock32.lib")
BOOL CFun::GetIPAddress(CString &IPAddress)
{
WORD wversion;
WSADATA wsData;
char name[255];
PHOSTENT hostinfo;
wversion=MAKEWORD(1,1);
char *ip;
if(WSAStartup(wversion,&wsData)==0)
{
if(gethostname(name,sizeof(name))==0)
{
if((hostinfo=gethostbyname(name))!=NULL)
{
int count=0;
while(hostinfo->h_addr_list[count])
{
ip=inet_ntoa(*(struct in_addr*)hostinfo->h_addr_list[count]);
CString st;st.Format("%s",ip);
IPAddress+=st;
++count;
}
}
else return FALSE;
}
else return FALSE;
}
else return FALSE;
return TRUE;
}
Moving a Captionless dialog
void CYourDialog::OnLButtonDown(UINT nFlags, CPoint point)
{
CDialog::OnLButtonDown(nFlags,point);
PostMessage(WM_NCLBUTTONDOWN, HTCAPTION, MAKELPARAM(point.x,point.y));
}
Creating a Hollow brush
CBrush *br=CBrush::FromHandle((HBRUSH)GetStockObject(HOLLOW_BRUSH));
Reading Bitmap from a file
HBITMAP hbitmap=(HBITMAP) ::LoadImage( AfxGetApp()->m_hInstance,
"c:\\test.bmp",
IMAGE_BITMAP,
LR_DEFAULTSIZE,
LR_DEFAULTSIZE,
LR_LOADFROMFILE);
Painting background with an image
BOOL CYourDialog::OnEraseBkgnd(CDC* pDC)
{
CBitmap mybitmap;
mybitmap.LoadBitmap(IDB_BITMAP1);
CDC mymemdc;
mymemdc.CreateCompatibleDC(pDC);
mymemdc.SelectObject(&mybitmap);
PDC->BitBlt(0,0,100,100,&mymemdc,0,0,SRCCOPY);
return 1;
}
Sending message to all windows
::SendMessage(HWND_BROADCAST,WM_CLOSE,0,0);
Registering an extension for your application
The following function can be used with any type of VC applications (Dialog based, SDI, MDI....). The core is, the following code will register its application directly to the Registry. Doc/View Architecture has its own way to register its document's extension (CWinApp::RegisterShellFileTypes(BOOL bCompat=FALSE)
).
BOOL RegisterExtension(CString sExt, CString sDescription)
{
sDescription.Replace(" ","");
sExt.Replace(" ","");
if(sExt.IsEmpty()) return FALSE;
if(sDescription.IsEmpty()) return FALSE;
sExt.Replace(".","");
sExt="."+sExt;
CString str=GetCommandLine();
CString app;
int index=str.Find(":",0);
index=str.Find(":",index+1);
if(index==-1) app=str;
else app=str.Mid(0,index-1);
app.Replace("\"","");
app+=" \"%1\"";
HKEY hkey;
RegOpenKeyEx(HKEY_CLASSES_ROOT,"",0,KEY_QUERY_VALUE,&hkey);
DWORD dw;
RegCreateKeyEx(hkey, sExt.operator LPCTSTR() , 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL,&hkey, &dw );
CString key=sDescription;
RegSetValueEx(hkey,"",0,REG_SZ,(BYTE *)key.operator LPCTSTR(),
key.GetLength());
RegCloseKey(hkey);
RegOpenKeyEx(HKEY_CLASSES_ROOT,"",0,KEY_QUERY_VALUE,&hkey);
RegCreateKeyEx (hkey, key, 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL, &hkey, &dw);
RegCreateKeyEx (hkey, "shell", 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL,&hkey, &dw);
RegCreateKeyEx (hkey, "open", 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL,&hkey, &dw);
RegCreateKeyEx (hkey, "command", 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL,&hkey, &dw);
RegSetValueEx(hkey,"",0,REG_SZ, (LPBYTE)(LPCTSTR)app,app.GetLength());
RegCloseKey(hkey);
RegOpenKeyEx(HKEY_CLASSES_ROOT,key,0,KEY_QUERY_VALUE,&hkey);
RegCreateKeyEx (hkey, "DefaultIcon", 0L, NULL,
REG_OPTION_NON_VOLATILE,
KEY_ALL_ACCESS,
NULL,&hkey, &dw);
app.Replace(" \"%1\"",",0");
RegSetValueEx(hkey,"",0,REG_SZ, (LPBYTE)(LPCTSTR)app,app.GetLength());
RegCloseKey(hkey);
return TRUE;
}
Getting screen resolution
void GetScreenResolution(int &xValue, int &yValue)
{
xValue = GetSystemMetrics ( SM_CXSCREEN ) ;
yValue = GetSystemMetrics ( SM_CYSCREEN ) ;
}
Getting path of executable for a file
char buff [MAX_PATH] ;
FindExecutable ( "C:\\myhtml.htm", NULL, buff ) ;
Changing color of a progress bar control
CProgressCtrl::SendMessage ( PBM_SETBARCOLOR, 0, RGB ( 255, 0, 0 ) ) ;
Setting a system wide cursor
Define OEMRESOURCE
in stdafx.h.
#define OEMRESOURCE
HCURSOR hcur1 = AfxGetApp()->LoadCursor(IDC_YOURCURSOR);
HCURSOR hcur2 = CopyCursor(hcur1);
SetSystemCursor(hcur2,OCR_NORMAL);
Getting directory list in your combobox
m_combo.Dir ( DDL_DIRECTORY, "C:\\Windows\\*.*" ) ;
m_combo.SetCurSel ( 1 ) ;
Parsing your commandline information
CCommandLineInfo cmdInfo;
AfxGetApp()->ParseCommandLine(cmdInfo);
MessageBox(cmdInfo.m_strFileName)
to be continued...
Dear Friends
I didn't describe any of the codes above. I have not enough time to spend for that. Just I have presented the code.
None of the articles can satisfy one's expectations. But, each article should be a seed for your technical growth. Thus, I believe that this would be a seed. Thank you all.
Naren started coding during 1999 with FORTRAN, then COBOL, PASCAL, C, C++, VC++ ..... C#, Java, ASP so on, till today. He claims himself as techie who loves coding, but he is not even sure which technology or platform he loves, most of the time Windows, some time WinCE, some time Linux, nowadays Android and embedded platforms. He can do some query stuffs with Oracle, SQL Server, MySQL. He strongly believes that C/C++ is a must for all programmers, "if you know C/C++, you can do programming on any language". He is an electronic gadget guy who likes to buy small gadgets all the time, at least he will do window shopping on a gadget shop. His interest always have been with Automation in any form, call it a little automated program sitting in his Laptop or a home automation program runs on his mobile. Apart from coding, he likes to do...???