DecimalSeparator: Key.OemPeriod vs Key.Decimal

[Koen]

Let me start by setting some context:

• our customers mostly live in Flanders, Belgium; overhere, the default culture nl-BE has  NumberDecimalSeparator = comma, and NumberGroupSeparator = blank space
• in this post, I will make a clear distinction between "Key.OemPeriod", being the 'regular' period on a keyboard, and "Key.Decimal", being the period on the numpad

Now, most Belgians have a keyboard layout of Belgium - Period. This means that:

• While typing text in for instance MS Word, the "Key.Decimal" will be interpreted as a period
• Mathematical software, like for instance MS Excel, will Always interpret the "Key.Decimal" as a decimal separator. 
  

      (yes, that's right, even though the NumberDecimalSeparator for the nl-BE culture is a comma).


Up to the RadNumericUpDown.
When the culture is set to nl-BE, this control interprets the comma as a decimal separator. So far so good.
However, when the "Key.Decimal" is pressed, this is not interpreted as a decimal separator, but just like a "Key.OemPeriod" is.
This is not the expected behavior; it should be interpreted as a decimal separator.

I'd consider this is a bug.
Is there any work-around for this issue?

I tried creating a behavior that would handle the TextBox's PreviewKeyDown event.
This kind of works, but it has some side effects which makes it not perfect. Any other way to handle this?


Thanks for your time,
Koen

[Koen]

For anyone running into the same issue, this is the behavior I finally ended up using.


public static class RadNumericUpDownBehavior

 {

 

     /// <summary>

     /// Makes sure that the num-pad period is interpreted as a decimal separator.

     ///

     /// For culture nl-BE, the NumberDecimalSeparator = comma, the NumberGroupSeparator = blank space.

     /// There is a clear distinction between "Key.OemPeriod", being the 'regular' period on a keyboard, and "Key.Decimal", being the period on the num-pad.

     ///

     /// For keyboard layout of Belgium - Period. This means that:

     /// - while typing text in for instance MS Word, the "Key.Decimal" will be interpreted as a period

     /// - mathematical software, like for instance MS Excel, will Always interpret the "Key.Decimal" as a decimal separator.

     ///                         (yes, that's right, even though the NumberDecimalSeparator for the nl-BE culture is a comma).

     ///

     /// When the culture is set to nl-BE, Telerik's RadNumericUpDown interprets the comma as a decimal separator. So far so good.

     /// However, when the "Key.Decimal" is pressed, this is not interpreted as a decimal separator, but just like a "Key.OemPeriod" is.

     /// This behavior fixes that and interpretes the "Key.Decimal" as a decimal separator.

     ///

     /// Was posted on Telerik forum: http://www.telerik.com/community/forums/wpf/numeric-up-down.aspx

     /// </summary>

     public static readonly DependencyProperty ForceNumPadPeriodDecimalSeparatorProperty =

         DependencyProperty.RegisterAttached("ForceNumPadPeriodDecimalSeparator", typeof(bool), typeof(RadNumericUpDownBehavior), new UIPropertyMetadata(false, OnForceNumPadPeriodDecimalSeparatorChanged));

 

     public static bool GetForceNumPadPeriodDecimalSeparator(RadNumericUpDown radNumericUpDown)

     {

         return (bool)radNumericUpDown.GetValue(ForceNumPadPeriodDecimalSeparatorProperty);

     }

 

     public static void SetForceNumPadPeriodDecimalSeparator(RadNumericUpDown radNumericUpDown, bool value)

     {

         radNumericUpDown.SetValue(ForceNumPadPeriodDecimalSeparatorProperty, value);

     }

 

     private static readonly FieldInfo TextBoxField = typeof(RadNumericUpDown).GetField("textBox", BindingFlags.Instance | BindingFlags.NonPublic);

 

     private static void OnForceNumPadPeriodDecimalSeparatorChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e)

     {

         if (TextBoxField == null)

             throw new InvalidOperationException("Failed to apply 'ForceNumPadPeriodDecimalSeparator'. Cannot find textBox field on type RadNumericUpDown.");

         var radNumericUpDown = (RadNumericUpDown)dependencyObject;

         if (GetForceNumPadPeriodDecimalSeparator(radNumericUpDown))

             radNumericUpDown.PreviewKeyDown += RadNumericUpDown_PreviewKeyDown;

         else

             radNumericUpDown.PreviewKeyDown -= RadNumericUpDown_PreviewKeyDown;

     }

 

     private static void RadNumericUpDown_PreviewKeyDown(object sender, KeyEventArgs e)

     {

         // Key.Decimal = Numpad . and Key.OemPeriod = Keypad .

         if (e.Key != Key.Decimal)

             return;

 

         e.Handled = true;

         var radNumericUpDown = (RadNumericUpDown)sender;

         var textBox = (TextBox)TextBoxField.GetValue(radNumericUpDown);

         var decimalSeparator = radNumericUpDown.ValueFormat == ValueFormat.Currency

                                    ? GetNumberFormatInfo(radNumericUpDown).CurrencyDecimalSeparator

                                    : GetNumberFormatInfo(radNumericUpDown).NumberDecimalSeparator;

 

         // Simulate the normal RadNumericUpDown behavior when all text is selected:

         // when a decimal separator is typed, clear all text and continue at caret position next to separator.

         if (textBox.SelectionLength == textBox.Text.Length)

         {

             textBox.Text = decimalSeparator;

             textBox.Select(textBox.Text.Length, 0);

         }

         else

         {

             var caretLocation = textBox.SelectionStart;

             textBox.Text = textBox.Text.Insert(caretLocation, decimalSeparator);

             textBox.Select(caretLocation + 1, 0);

         }

     }

 

     /// <summary>

     /// This is the same implementation as the internal one on RadNumericUpDown

     /// </summary>

     /// <param name="radNumericUpDown"></param>

     /// <returns></returns>

     internal static NumberFormatInfo GetNumberFormatInfo(RadNumericUpDown radNumericUpDown)

     {

         return radNumericUpDown.NumberFormatInfo ?? CultureInfo.CurrentCulture.NumberFormat;

     }

 }

[Koen]

To close this issue, I think there are 2 bugs in the RadNumericUpDown:


- It interpretes "Key.Decimal" and  "Key.OemPeriod" as being the same, while "Key.Decimal" should always be a decimal separator.
- It uses NumberStyles.Any to parse text, instead of choosing the right NumberStyle depending on RadNumericUpDown.ValueFormat,
  causing http://www.telerik.com/community/forums/wpf/numeric-up-down/numericupdown-allows-to-enter-commas.aspx
 

Regards,
Koen

[Konstantina]

Hi Koen,

Thank you for your feedback.

We will consider making difference between the pressing of Key.Decimal and Key.OemPeriod keys if we receive more clients' requests. Now, they mean the same for RadNumericUpDown - a dot.

Regards,
Konstantina
Telerik

[Jakkie Esschert van den]

Being Dutch I'd like to see the same, or perhaps a mode which treats both a dot and a comma as decimal separator. Nobody here seems to use thousand separators, so both a dot and a comma are generally considered to be a decimal separator. 

[Vladi]

Hello,

As Konstantina mentioned if we get enough demand for such feature we may consider implementing it as built-in feature in one of our future releases of RadNumericUpDown control.

You could workaround this issue by handling the inputted symbols for example in the PreviewKeyDown event of the control and implementing a parsing that would consider the entered symbol as decimal separator.

Regards,
Vladi
Telerik

[Technique]

Hi,

I am french Candian and we also use both the dot and the comma as decimal separators.
The comma is mostly used though.

In every software that uses numbers, the Key.Decimal is mapped to the culture of the computer.
I really don't get why you didn't implement this as it is a normal behavior and it seems to be a source of problem for the most part of the world.

I am using the GridView and this bugs me quite a lot, if we write "999.99" when the cell ends its edition, the value saved is "0,00" only because of the dot. It is frustrating to have to customize all the Telerik controls we use in order to have a basic functionality.

If there is a fix or a workaround for this, please let me know.

[Vladi]

Hello,

As we see that such feature may be desirable to be implemented as a built-in feature in the RadNumericUpDown control you can use our feedback portal where you can add any feature request, bug report and any general feedback about RadControls for WPF and Siverlight.

You can access the feedback portal from here.

Regards,
Vladi
Telerik

[Tore]

Hello, I got the desired behavior for the Norwegian culture using only XAML, we we also use comma as the NumberDecimalSeparator. Also here, users will be used to using both the comma or the period as the decimal separator. 

Example:

Where the XML namespace global is: 
 xmlns:global="clr-namespace:System.Globalization;assembly=mscorlib"

<telerik:RadNumericUpDown IsEnabled="{Binding IsEditMode, FallbackValue=false}" 
Value="{Binding TheaterTemperatureSurgeryStart}" Width="50" Minimum="15" Maximum="30" SmallChange="1" 
Margin="2" ValueFormat="Numeric">
    <telerik:RadNumericUpDown.NumberFormatInfo>
       <global:NumberFormatInfo NumberDecimalDigits="0" NumberDecimalSeparator="," />
    </telerik:RadNumericUpDown.NumberFormatInfo>
</telerik:RadNumericUpDown> 

[Kalin]

Hi Tore,

The best solution I can suggest you for this particular scenario would be to insert the NumberDecimalSeparator of the NumericUpDown control whenever "," or "." are typed in the input field. In order words to insert for example "." in the both cases. You can achieve that by hooking to the PreviewKeyDown of the control and implementing the following event handler:

private void RadNumericUpDown_PreviewKeyDown(object sender, KeyEventArgs e)
{
    var num = sender as RadNumericUpDown;

    if (e.Key == Key.Decimal || e.Key == Key.OemComma || e.Key == Key.OemPeriod)
    {
        var textBox = e.OriginalSource as System.Windows.Controls.TextBox;
        if (!textBox.Text.Contains(num.NumberDecimalSeparator))
        {
            textBox.Text += num.NumberDecimalSeparator;
            textBox.CaretIndex = textBox.Text.Length;
        }

        e.Handled = true;
    }
}

Hope this helps.

Regards,
Kalin
Telerik

 

 

[Jolanta]

Hi, 

is there any possibility to set a decimal and group separator for numeric format, for the whole report, in the standalone telerik designer?

[Stef]

Hi Jolanta,

I believe your question is related to Telerik Reporting and Report Globalization.

Please check the linked article and if you need further help, post a question in the corresponding product's forum. Feel free to use the support ticketing system as well, where we can exchange projects and code examples.

Regards,
Stef
Telerik