wzdxchng.cpp

《vc++扩展编程实例》源码。运用Visual C++ 5.0或6.0的高级编程技巧

// WzdXchng 
//

#include "stdafx.h"
#include "WzdXchng.h"
#include "WzdStr.h"
#include <afxpriv.h>

/////////////////////////////////////////////////////////////////////////////
// CWzdXchng


void AFXAPI DDX_Text(CDataExchange* pDX, int nIDC, CByteArray& value)
{
	CWzdString str;
	HWND hWndCtrl = pDX->PrepareEditCtrl(nIDC);
	if (pDX->m_bSaveAndValidate)
	{
		int nLen = ::GetWindowTextLength(hWndCtrl);
		::GetWindowText(hWndCtrl, str.GetBufferSetLength(nLen), nLen+1);
		str.ReleaseBuffer();
		int size=str.GetLength();
		if (size%2)
		{
			AfxMessageBox("Please enter even number of digits.");
			pDX->Fail();            // throws exception
		}
		size/=2;
		value.SetSize(size);
		str.GetBinary(value.GetData(),size);
	}
	else
	{
		str.PutBinary(value.GetData(),value.GetSize());
		AfxSetWindowText(hWndCtrl, str); //sets window text only if it's different
	}
}

void AFXAPI DDV_MaxChars(CDataExchange* pDX, CByteArray const& value, int nBytes)
{
	if (pDX->m_bSaveAndValidate && value.GetSize() > nBytes)
	{
		CString str;
		str.Format("Maximum characters you can enter is %d!",nBytes);
		AfxMessageBox(str, MB_ICONEXCLAMATION);
		str.Empty(); // will not return after exception
		pDX->Fail();
	}
	else if (pDX->m_hWndLastControl != NULL && pDX->m_bEditLastControl)
	{
		// set edit box not to allow more then these bytes
		// note that this function depends on being called right after the DDX function
		::SendMessage(pDX->m_hWndLastControl, EM_LIMITTEXT, nBytes*2, 0);
	}
}