MFC General: How to process command line arguments in a MFC application?

[kirants]

Q: How to process command line arguments in a MFC application?

A:

• Derive a class from CCommandLineInfo, say 'CCustomCommandLineInfo'
  
  
  

  class CCustomCommandLineInfo : public CCommandLineInfo

  
  
• Add virtual method 'ParseParam()'
  
  
  

  {
    virtual void ParseParam(const char* pszParam, BOOL bFlag, BOOL bLast);
  }

• In 'ParseParam()', check the 'pszParam' passed. Note, that 'ParseParam()' will be called as many times as the tokens being used while launching the command line. So, if you call 'Yourapp.exe /e /o /whatever', you will see 3 calls to 'ParseParam()' each with "/e", "/o", "/whatever".
  
  
  

  class CCustomCommandLineInfo : public CCommandLineInfo
  {
    CCustomCommandLineInfo()
    {
      m_bExport = m_bOpen = m_bWhatever = FALSE;
    }
  
    //for convenience maintain 3 variables to indicate the param passed. 
    BOOL m_bExport;       //for /e
    BOOL m_bOpen;         //for /o
    BOOL m_bWhatever;     //for /whatever
   
    //public methods for checking these.
  public:
    BOOL IsExport() { return m_bExport; };
    BOOL IsOpen() { return m_bOpen; };
    BOOL IsWhatever() { return m_bWhatever; };
     
    virtual void ParseParam(const char* pszParam, BOOL bFlag, BOOL bLast)
    {
      if(0 == strcmp(pszParam, "/o"))
      {
        m_bOpen = TRUE;
      } 
      else if(0 == strcmp(pszParam, "/e"))
      {
        m_bExport = TRUE;
      }
      else if(0 == strcmp(pszParam, "/whatever"))
      {
        m_bWhatever = TRUE;
      }
    }
  };

• Instantiate an object of this class in 'InitInstance()' and parse it like below.
  
  
  

  BOOL CYourApp::InitInstance()
  {
    // Do all the stuff you want to do, like registering document tempates etc.
  
    CCustomCommandLineInfo oInfo;
    ParseCommandLine(oInfo);
    // ....
  }

• And then check
  
  
  

  BOOL CYourApp::InitInstance()
  {
    // Do all the stuff you want to do, like registering document tempates etc.
  
    CCustomCommandLineInfo oInfo;
    ParseCommandLine(oInfo);
  
    if(oInfo.IsExport())
    {
      // Do something
    }
    else if(oInfo.IsWhatever())
    {
      // Do whatever
    }
  
    // ....
  }

[Kvorak]

Just as a note, this does not work in Visual Studio if the Configuration Properties->General->Character Set field is set to Unicode. For that, the pszParam must be of type LPCTSTR. Just wanted to point that out in case it wasn't obvious to anybody else.