C++ Code Example For A List Box

class TVendDlg : public TDialog {
public:
    virtual void SetupWindow();
    virtual void VendDel(RTMessage Msg)
      = [ID_FIRST + ID_DELX_];
    virtual void VendChs(RTMessage Msg)
      = [ID_FIRST + ID_CHS1_];
    virtual void VendPrn(RTMessage Msg)
      = [ID_FIRST + ID_VPRN_];
    char Vncode[MAXCCODE];
    char Vnname[MAXCNAME];
    char Vnstreet[MAXCSTREET];
    char Vnstreet2[MAXCSTREET];
    char Vncity[MAXCCITY];
    char Vnstate[MAXCSTATE];
    char Vnzip[MAXCZIP];
    char VnTell1[MAXCTF1];
    char VnFax1[MAXCTF1];
    char Vnatt[MAXATT];
    char VnPaytrm[MAXTERM];
    char VnNote1[MAXNOTE];
    char VnNote2[MAXNOTE];

TEdit *Edit1,*Edit2,*Edit3,*Edit4,*Edit5,*Edit6,*Edit7,*Edit8,*Edit9,*Edit10,
*Edit11,*Edit12,*Edit13;

    TVendDlg(PTWindowsObject AParent, LPSTR name);
    virtual BOOL CanClose();
};

class ListBoxDialog : public TDialog
{
public:
  ListBoxDialog(PTWindowsObject AParent, LPSTR AName)
    : TDialog(AParent, AName) {};
  virtual void SetupWindow();
  virtual void HandleListBoxMsg(RTMessage Msg)
    = [ID_FIRST + ID_LISTBOX];
};

void TVendDlg::VendChs(RTMessage)
{
  int       a;
  streambuf *inn = cin.rdbuf();
  ifpstream ifile;
  Globalvar = 0;
  GetApplication()->ExecDialog(new ListBoxDialog(this, "VENDORDIALOG"));

    // if the Global variable, “Globalvar” is set to 1 from the
    // “ListBoxDialog::HandleListBoxMsg(RTMessage Msg)” member
    // function, then proceed.
    if( Globalvar == 1) {

    // set the global flag, “hasbeenselected”, to signal a vendor
    // has been selected from the list box.
    hasbeenselected = 1;

        // display the retrieved vendor data in the vendor data entry
        // screen after the selection in the list box has been clicked
        // by the user. the data for the selected vendor will be
                // assigned to the edit controls in the vendor data entry
                // screen.
        ifile.open("vend.txt", ios::in | ios::binary);
        inn = ifile.rdbuf();
        // position the filestream ofthe binary vendor
        // data file to the calculated filestream offset
        // value of the selected list box item.
        inn -> seekpos(offsetvar, ios::in);
        for(a=0; a<MAXCCODE-1; a++) Vncode[a] = ifile.readByte();
        Vncode[MAXCCODE-1] = 0;
        Edit1->SetText(Vncode);
        for(a=0; a<MAXCNAME-1; a++) Vnname[a] = ifile.readByte();
        Vnname[MAXCNAME-1] = 0;
        Edit2->SetText(Vnname);
        for(a=0; a<MAXCSTREET-1; a++) Vnstreet[a] = ifile.readByte();
        Vnstreet[MAXCSTREET-1] = 0;
        Edit3->SetText(Vnstreet);
        for(a=0; a<MAXCSTREET-1; a++) Vnstreet2[a] = ifile.readByte();
        Vnstreet2[MAXCSTREET-1] = 0;
        Edit4->SetText(Vnstreet2);
        for(a=0; a<MAXCCITY-1; a++) Vncity[a] = ifile.readByte();
        Vncity[MAXCCITY-1] = 0;
        Edit5->SetText(Vncity);
        for(a=0; a<MAXCSTATE-1; a++) Vnstate[a] = ifile.readByte();
        Vnstate[MAXCSTATE-1] = 0;
        Edit6->SetText(Vnstate);
        for(a=0; a<MAXCZIP-1; a++) Vnzip[a] = ifile.readByte();
        Vnzip[MAXCZIP-1] = 0;
        Edit7->SetText(Vnzip);
        for(a=0; a<3; a++) VnTell1[a] = ifile.readByte();
        VnTell1[3] = '-';
        for(a=0; a<3; a++) VnTell1[4+a] = ifile.readByte();
        VnTell1[7] = '-';
        for(a=0; a<4; a++) VnTell1[8+a] = ifile.readByte();
        VnTell1[MAXCTF1-1] = 0;
        Edit8->SetText(VnTell1);
        for(a=0; a<3; a++) VnFax1[a] = ifile.readByte();
        VnFax1[3] = '-';
        for(a=0; a<3; a++) VnFax1[4+a] = ifile.readByte();
        VnFax1[7] = '-';
        for(a=0; a<4; a++) VnFax1[8+a] = ifile.readByte();
        VnFax1[MAXCTF1-1] = 0;
        Edit9->SetText(VnFax1);
        for(a=0; a<MAXATT-1; a++) Vnatt[a] = ifile.readByte();
        Vnatt[MAXATT-1] = 0;
        Edit10->SetText(Vnatt);
        for(a=0; a<MAXTERM-1; a++) VnPaytrm[a] = ifile.readByte();
        VnPaytrm[MAXTERM-1] = 0;
        Edit11->SetText(VnPaytrm);
        for(a=0; a<MAXNOTE-1; a++) VnNote1[a] = ifile.readByte();
        VnNote1[MAXNOTE-1] = 0;
        Edit12->SetText(VnNote1);
        for(a=0; a<MAXNOTE-1; a++) VnNote2[a] = ifile.readByte();
        VnNote2[MAXNOTE-1] = 0;
        Edit13->SetText(VnNote2);
        ifile.close();

    }

  }

  VENDORDIALOG DIALOG DISCARDABLE LOADONCALL PURE MOVEABLE 30, 18, 208, 108
STYLE WS_POPUP | WS_DLGFRAME
FONT 10, "COURIER"
BEGIN
  CONTROL "Vendor Name                   Vend. Code   ", 10055, "static", SS_LEFT | WS_CHILD, 20, 3, 188, 8
  CONTROL "&Exit" IDCANCEL, "BUTTON", WS_CHILD | WS_VISIBLE | WS_TABSTOP, 20, 93, 48, 12
  CONTROL "Vendor Listing", 10056, "static", SS_LEFT | WS_CHILD, 75, 93, 200, 8
  CONTROL "LISTBOX" ID_LISTBOX, "LISTBOX", WS_CHILD | WS_VISIBLE | WS_BORDER | WS_VSCROLL | 0x3L, 20, 15, 168, 73
END
}

oid ListBoxDialog::SetupWindow()
{
  long int   fileoffset, sizeofdatafile;
  int        a,fileinfo,t;
  streambuf  *inn = cin.rdbuf();
  ifpstream  ifile;

  // this will loop around the “vend.txt” binary data file of
  // vendors and add a data record to the list box, which includes
  // vendor name and vendor code.
  fileinfo = open("vend.txt", ios::in | ios::binary);
  sizeofdatafile = filelength(fileinfo);
  close(fileinfo);
  ifile.open("vend.txt", ios::in | ios::binary);
  inn = ifile.rdbuf();
  fileoffset  = 0;
  do {

        // initialize the char array, “char_array”, with space characters.
        for(a=0; a<100; a++) char_array[a] = 32;

        // read the vendor name and vendor code from the file stream.
        inn -> seekpos(fileoffset, ios::in);
            for(a=0; a<MAXCCODE-1; a++) char_array[32+a] = ifile.readByte();
        inn -> seekpos(fileoffset+MAXCCODE-1, ios::in);
        for(a=0; a<MAXCNAME-1; a++) char_array[a] = ifile.readByte();

            // mask out white space characters.
            for(a=0; a<100; a++) {
            if(char_array[a]<33 || char_array[a]>126) char_array[a] = 32;
            }

                // read the sequential position of the record in the binary text file.
                inn -> seekpos(fileoffset+VENDLEN-5, ios::in);
                for(a=0; a<5; a++) char_array[70+a] = ifile.readByte();
                // null space the end of the char array to  suppress trailing random chars.
                char_array[99] = 0;

                    // convert the char array to lower case.
                    strlwr(char_array);

                        // add the vendor name and vendor code pair to the list box control.
                        SendDlgItemMsg(ID_LISTBOX, LB_ADDSTRING, 0, (LONG) char_array);

  // advance to the next record in the binary text file.
  fileoffset = fileoffset + VENDLEN;

  } while(fileoffset<sizeofdatafile);

  ifile.close();

}

void ListBoxDialog::HandleListBoxMsg(RTMessage Msg)
{
  long int   a, convert_to_number[5];
  DWORD      Idx;

  // if the exit button is clicked, then exit and reset global variable to 0.
  if ( Msg.LP.Hi == LBN_SELCANCEL ) Globalvar = 0;

    // if a selection is made, then reset the global variable to 1 and proceed to calculate the
    // filestream offset after getting the list box index of the selection, “Idx”.
    if ( Msg.LP.Hi == LBN_SELCHANGE ) {

        // initialize the char array, “char_array”, with space characters.
        for(a=0; a<80; a++) char_array[a] = 32;

        Globalvar = 1;

        // get the index of the selected list box item.
        Idx = SendDlgItemMsg(ID_LISTBOX, LB_GETCURSEL, 0, 0L);

        char_array[79] = 0;

        // use the index to retrieve the contents of the selected list box row into a char array, “char_array”.
        SendDlgItemMsg(ID_LISTBOX, LB_GETTEXT, (WORD)Idx, (DWORD) char_array);

        // close the list box window after retrieving info into the char array from above.
        CloseWindow();

                // this will take the auto-generated sequential
            // position of the vendor record stored in each record of the binary text file, “vend.txt”
            // from the char array and convert it to a numerical value to be multiplied by the defined constant,
            // “VENDLEN”. this will produce the filestream offset I call “offsetvar”, which is used to locate the
            // vendor data in the member function “VendChs” of the “TVendDlg” dialog class, which will populate
            // the edit controls in the vendor data entry screen.
                for(a=0; a<5; a++) {
                convert_to_number[a] = 0;
                if(char_array[70+a] == 48) convert_to_number[a] = 0;
                if(char_array[70+a] == 49) convert_to_number[a] = 1;
                if(char_array[70+a] == 50) convert_to_number[a] = 2;
                if(char_array[70+a] == 51) convert_to_number[a] = 3;
                if(char_array[70+a] == 52) convert_to_number[a] = 4;
                if(char_array[70+a] == 53) convert_to_number[a] = 5;
                if(char_array[70+a] == 54) convert_to_number[a] = 6;
                if(char_array[70+a] == 55) convert_to_number[a] = 7;
                if(char_array[70+a] == 56) convert_to_number[a] = 8;
                if(char_array[70+a] == 57) convert_to_number[a] = 9;
            }
                offsetvar = ( (convert_to_number[0] * 10000) + (convert_to_number[1] * 1000) + (convert_to_number [2] * 100) + (convert_to_number [3] * 10 ) + (convert_to_number[4] * 1) ) * VENDLEN;

    }

}