Get Current Input Language NumberDecimalSeparator?

Question

Hallo,

I am trying to get NumberDecimalSeparator for the current input language.

I have a system with English (OS language) and I have a german keyboard.

following code still gives ". " dot as a decimal separator but the right one is ",". How do i get the decimal separator from the keyboard?.

InputLanguage.CurrentInputLanguage.Culture.NumberFormat.NumberDecimalSeparator

I have textboxes in my application and i want to allow the numbers with only "," or "." depending on the keyboard or language settings. How do i do that?.

Thanks

Answer 1

The settings come from what the user's locale settings are, not any attached keyboard. In the user's local settings they specify what the decimal separator (and other values) are to use. Again, this is completely independent of any keyboard characters.

To get the current UI settings (based upon the user's settings) then you use CultureInfo.CurrentUICulture. This is the system settings overridden with any user-customized settings. There is a related property CultureInfo.CurrentCulture which is the non-UI variant. Honestly I don't know why you'd ever need it.

Once you have the CultureInfo for the UI then NumberFormat.CurrentDecimalSeparator is what you want.

   ' Get current user's decimal separator  
   Dim separator = System.Globalization.CultureInfo.CurrentUICulture.NumberFormat.CurrentDecimalSeparator  

Note that most UIs automatically handle using the UI culture so you don't need to do anything special. You'd only need it if you wanted to do custom parsing but also note that the framework can handle this as well.

   Dim text = "1.234"  
   Dim result As Double  
     
   If (Double.TryParse(text, NumberStyles.Any., CultureInfo.CurrentUICulture, [ByRef] result))  
      # Valid double  
   End If  

You can customize NumberStyles to limit the options.

Alternatively consider using a MaskedTextBox if your UI framework supports it.

Answer 2

Maybe you can test with NLS API
Like :

            Dim sbDataUser As StringBuilder = New StringBuilder(128)
            If (GetLocaleInfoEx(LOCALE_NAME_USER_DEFAULT, LOCALE_SDECIMAL, sbDataUser, sbDataUser.Capacity) <> 0) Then
                Dim sbDataSystem As StringBuilder = New StringBuilder(128)
                If (GetLocaleInfoEx(LOCALE_NAME_SYSTEM_DEFAULT, LOCALE_SDECIMAL, sbDataSystem, sbDataSystem.Capacity) <> 0) Then
                    MessageBox.Show(String.Format("Decimal Separator (User) : {0}{1}Decimal Separator (System) : {2}", sbDataUser.ToString(), vbCrLf, sbDataSystem.ToString()), "Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
                End If
            End If

with declarations :

<DllImport("Kernel32.dll", SetLastError:=True, CharSet:=CharSet.Unicode)>
Public Shared Function GetLocaleInfoEx(lpLocaleName As String, LCType As UInteger, lpLCData As StringBuilder, cchData As Integer) As Integer
End Function

Public Const LOCALE_NAME_USER_DEFAULT = Nothing
Public Const LOCALE_NAME_INVARIANT = ""
Public Const LOCALE_NAME_SYSTEM_DEFAULT = "!x-sys-default-locale"

Public Const LOCALE_SDECIMAL = &HE  ' Decimal separator, eg "." For 1,234.00