lobsampledlg.cpp

vc在线考试系统源码

/************************************************************
@author  Chandar
@version 1.0
Development Environment        :  Visual C++ 6.0
Name of the File               :  LOBSampleDlg.cpp
Creation/Modification History  :
                                  01-Aug-2001     Created

File Overview

This file implements the class CLOBSampleDlg used to handle the
dialog box function and events
***************************************************************/


#include "stdafx.h"
#include "LOBSample.h"
#include "LOBSampleDlg.h"


#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CLOBSampleDlg dialog


/*********************
Constructor definition
**********************/
CLOBSampleDlg::CLOBSampleDlg(CWnd* pParent /*=NULL*/)
	: CDialog(CLOBSampleDlg::IDD, pParent)
{  
	//{{AFX_DATA_INIT(CLOBSampleDlg)
	//}}AFX_DATA_INIT
	// Note that LoadIcon does not require a subsequent DestroyIcon in Win32
	m_hIcon = AfxGetApp()->LoadIcon(IDR_MAINFRAME);
	
	//Set the variables for existing and new picture to empty string
	m_ExistingPicture="";
	m_NewPicture="";
}


void CLOBSampleDlg::DoDataExchange(CDataExchange* pDX)
{
	CDialog::DoDataExchange(pDX);
	//{{AFX_DATA_MAP(CLOBSampleDlg)
	DDX_Control(pDX, IDC_COMBOPRODUCT, m_product);
//	DDX_Control(pDX, IDC_NEWPICTURE, m_newPicture);
//	DDX_Control(pDX, IDC_EXISTPICTURE, m_ExistPicture);
	//}}AFX_DATA_MAP
}

BEGIN_MESSAGE_MAP(CLOBSampleDlg, CDialog)
	//{{AFX_MSG_MAP(CLOBSampleDlg)
	ON_WM_PAINT()
	ON_WM_QUERYDRAGICON()
	ON_BN_CLICKED(IDC_BUTTON_BROWSE, OnButtonBrowse)
	ON_BN_CLICKED(IDC_BUTTON_UPDATE, OnButtonUpdate)
	ON_CBN_SELCHANGE(IDC_COMBOPRODUCT, OnSelchangeComboproduct)
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CLOBSampleDlg message handlers


/********************************************************************
This function is called just before displaying the dialog box to 
initialize dialog box
It calls the functions to retrieve the product  names 
from database and displays them in list box on dialog box
********************************************************************/
BOOL CLOBSampleDlg::OnInitDialog()
{
    CDialog::OnInitDialog();

	// Set the icon for this dialog.  The framework does this automatically
	//  when the application's main window is not a dialog
	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon
	
	// TODO: Add extra initialization here
    
	//Open the connection to database using ADODBHandler object
	BOOL check=dbObj.OpenDatabase();

	 if (check==TRUE)   //if connected
	 {
		 try
		 {
			  //Get the database function to get product names and ids
	          _RecordsetPtr pnames= dbObj.GetProductNames();
	          
	          
			  if (pnames!=NULL)

              //Loop till the end of recordset
	          while (!pnames->GetadoEOF())
			  {
                 //Get the product name. It is string type
		         _bstr_t name=pnames->Fields->GetItem("product_name")->GetValue().bstrVal;
	             
				 //Get the product id. It is integer type
				 long productId=pnames->Fields->GetItem("product_id")->GetValue().lVal;

				 //Add the product name to the list box on dialog box
	             int index=m_product.AddString(name);

				 //Add the product id for above name as item data of list box item
				 //This id is returned when list box item is selected
				 m_product.SetItemData(index,productId);

				 //Move to next row in the recordset
	             pnames->MoveNext();
				 
	             
			  }
            
       	      //Close the database connection    	 
	          dbObj.CloseDatabase();
		 }
		 //Catch COM errors
		 catch( _com_error &e)
		 { 
            // get info from _com_error
            _bstr_t error="Source: " + e.Source() + "Description: "+ e.Description();
	       	MessageBox(error,"Error");
		    EndDialog(0);   //End the dialog on error
		 }
		 //Catch unhandled exception
		 catch(...)
		 {
           	MessageBox("Unhandled Exception","Error");
		    EndDialog(0);
		 }
		

	 }
	 //if cannot connect to database, display message
	 else
	 {
		 MessageBox("Cannot Connect to Database","Connection Error");
         EndDialog(0);
	 }




	return TRUE;  // return TRUE  unless you set the focus to a control
}



/***************************************************************
This function is called whenever dialog box needs repainting 
ie whenever it is shown or resized or uncovered by other windows
It is used to paint the existing and new image of the 
product on the dialog box
****************************************************************/
void CLOBSampleDlg::OnPaint() 
{
	CPaintDC dc(this);
	if (IsIconic())
	{
		 // device context for painting

		SendMessage(WM_ICONERASEBKGND, (WPARAM) dc.GetSafeHdc(), 0);

		// Center icon in client rectangle
		int cxIcon = GetSystemMetrics(SM_CXICON);
		int cyIcon = GetSystemMetrics(SM_CYICON);
		CRect rect;
		GetClientRect(&rect);
		int x = (rect.Width() - cxIcon + 1) / 2;
		int y = (rect.Height() - cyIcon + 1) / 2;

		// Draw the icon
		dc.DrawIcon(x, y, m_hIcon);
	}
	//Redraw the dialog box to show the image on it
	else
	{
	    //check is existing picture is not empty 
		if (m_ExistingPicture!=(_bstr_t)"")
        {   
			//Set the rectangular area of dialog box foe existing image
			bounds.SetRect(213,92,420,280);
			
			//Load the image from image file
			image.Open(m_ExistingPicture);
		    
			//Draw the image on dialog box
			image.DrawImage(&dc, bounds);
			
		}
		//check if new picture is selected
		if (m_NewPicture!=(_bstr_t)"" && m_flag==FALSE)
		{
			//Load the new picture from file
		   image.Open(m_NewPicture);

		   //Set the rectangular area for drawing new image
		   bounds.SetRect(213,305,420,496);

           //Draw the image
		   image.DrawImage(&dc, bounds);
		}
		
			CDialog::OnPaint();
	}
}
/****************************************************************************
// The system calls this to obtain the cursor to display while the user drags
//  the minimized window.
*****************************************************************************/
HCURSOR CLOBSampleDlg::OnQueryDragIcon()
{
	return (HCURSOR) m_hIcon;
}


/*****************************************************************************
This function defines the message handler for click event of the Browse button
on dialog box.
******************************************************************************/
void CLOBSampleDlg::OnButtonBrowse() 
{
	 //create a common dialog box object. The parameter TRUE is for Open dialog
     // box. FALSE indicates SAVE dialog box

	  //set the files to be shown by Open File Dialog box
	  static char BASED_CODE filter[] = 
                "Image Files (*.bmp, *.jpg,*.gif)"\
                "|*.bmp;*.jpg;*.gif||";
     
	  CFileDialog cfdlg(TRUE,0, 0,0,filter, this);
       
	 
	  //Display the dialog box and get return value
	  if (cfdlg.DoModal()==IDOK)
	  {
        //Get the name of selected file into m_NewPicture variable
	    m_NewPicture =cfdlg.GetPathName();
	
		//Set m_flag to false
	    m_flag=FALSE;


		//Call the paint function of dialog box. FALSE indicates only some areas
		//need repainting. TRUE repaints whole dialog box
	    Invalidate(FALSE);
	  }
	 

}

/****************************************************************************
This function defines the message handler for the Update button on the dialog
box. It updates the new image for the selected product into the database
****************************************************************************/
void CLOBSampleDlg::OnButtonUpdate() 
{
     //Check if user has selected a product and new image file
	 if(m_product.GetCurSel()==CB_ERR || m_NewPicture==(_bstr_t)"")
		 
		 MessageBox("Select a Product and New Image");
	 
	 else
	 {
	    //Get the product id of the selected product   
     	int productid = m_product.GetItemData(m_product.GetCurSel());

		//Open database connection
	    BOOL check=dbObj.OpenDatabase();

	    if (check==TRUE)     //if connected
		{
          //update the image for the selected product
		  BOOL update=dbObj.SetImage(productid,m_NewPicture);

	      	  
		}
		//if cannot connect to database display message
	    else
		    MessageBox("Cannot Connect to Database","Connection Error");
	}	
	 m_NewPicture="";
	
}


/**************************************************************************
This function defines the message handler for selection change event of the
list box. It gets the product from list box and displays the existing image
from database onto the dialog box
**************************************************************************/
void CLOBSampleDlg::OnSelchangeComboproduct() 
{
	if(m_ExistingPicture!=(_bstr_t)"")
	{
		//Delete the temporary file created to dislay the image if it exists
		CFile::Remove(m_ExistingPicture); 

		//Set existing picture file string to empty string
		m_ExistingPicture="";
	}
	
	//Open database connection
	 BOOL check=dbObj.OpenDatabase();

	 if (check==TRUE)     //if connected
	 {
		  
		  BOOL  getimagecheck;
		  
		  //Get the product id of the selected product
          int productid=m_product.GetItemData(m_product.GetCurSel()); 
         
		 try
		 {
             //Get the image for seleted product from database
		     getimagecheck= dbObj.GetImage(productid);
	   
			if (!getimagecheck)   //if false
			{
				MessageBox("Image does not exists");
				m_ExistingPicture="";
			}
			else
		      m_ExistingPicture = dbObj.strCurAppPath +"image.bmp";
		  
		 	//Set the flag for painting the dialog box
		    m_flag=TRUE; 

			 
		 }
		 //Catch COM errors
         catch( _com_error &e)
		 {   
            // get info from _com_error
             _bstr_t error="Source: " + e.Source() + "Description: "+ e.Description();
	         MessageBox(error,"Error");
		     EndDialog(0);
		 }
		 //Catch Unhandled exceptions
		 catch(...)
		 {
           	 MessageBox("Unhandled Exception","Error");
		     EndDialog(0);
		 }

		 //Close database connection
          dbObj.CloseDatabase();
          
         if (m_NewPicture==(_bstr_t("")))
		 {    
			 //define a rectangular area covering new and old image frames
			 bounds.SetRect(212,92,421,494);
		 }
		 else
		 {
			 //Define a rectangular area covering  old image frame
			 bounds.SetRect(212,92,421,280);
			 
		      
		 }

		 //Paint the defined rect on dialog box
	     InvalidateRect(bounds);
		      
     }
	 //if not connected to database, display message
     else   
	 {
		 MessageBox("Cannot Connect to Database","Connection Error");
     }	 
     
}



/*********************************************************
This message handler is called when Exit button on dialog
box is clicked.
*********************************************************/
void CLOBSampleDlg::OnCancel() 
{
	// TODO: Add extra cleanup here
	if(m_ExistingPicture!=(_bstr_t)"")
	{
		//Delete the temporary file created to dislay the image if it exists
		CFile::Remove(m_ExistingPicture); 

		//Set existing picture file string to empty string
		m_ExistingPicture="";
	}
	
	CDialog::OnCancel();
}