Localized numeric editbox

• Download demo project - 23 Kb
• Download source - 1 Kb

Introduction

Microsoft provides to developers rich collection of GUI controls. The edit box control is very useful, but has one diasadvantage: it does not supports the numeric decimals. This article describes the creation of numeric edit box.

Background

The Microsoft's controls are localized. For example, if you change the local time format from the "Regional Options" dialog, CDateTimeCtrl change it time format. The presented numeric edit box is localized as well. By the creation time it loads the locale decimal point delimiter and use it. Here is the code:

///
/// Constructor.
///
CNumericEdit::CNumericEdit()
{
    // determine the decimal delimiter buffer size    
    const int nBuffLen = ::GetLocaleInfo( LOCALE_USER_DEFAULT, 
        LOCALE_SDECIMAL, NULL, 0 );
    _ASSERT( nBuffLen > 0 );    

    // get the decimal number delimiter    
    const int nResult = ::GetLocaleInfo( LOCALE_USER_DEFAULT, 
        LOCALE_SDECIMAL, 
        m_strDelim.GetBuffer(nBuffLen), nBuffLen );
    _ASSERT(nResult != 0);
    m_strDelim.ReleaseBuffer();    
}</CODE>

Using the code

You should do following steps:

1. Place the edit box control on the dialog.
2. Assotiate the CEdit dialog class member to the edit box control.
3. Include the "NumericEdit.h" to the your dialog class header.
4. Replace the CEdit with CNumericEdit.

   //
   // Example of using the code
   //
   #include "NumericEdit.h"
   
   // some code
   
   protected:
       // some code
   	
       CNumericEdit m_editNumeric;
   	
       // some code
   

Points of Interest

Microsoft says about WM_SETTINGCHANGE :

The system sends the WM_SETTINGCHANGE message to all top-level windows when the SystemParametersInfo function changes a system-wide setting or when policy settings have changed.

I checked it, it works. Currently the numeric edit box control sets it's locale by creation time. It will be much better the control to react to operation system changes. But the WM_SETTINGCHANGE message is sent only to top-level windows, not to child windows. The possible solution is to handle the WM_SETTINGCHANGE in main window and delegate the WM_SETTINGCHANGE message to all child windows, but it seams ugly. I continue find other solution of this problem.

History

• 12.08.2003 - First version of the code.

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