StringFormat, ConverterCulture, and Decimal Text Field Label

Question

I would like to solve the small quirk that I had. This is not a real quirk, but rather a behavior that I would like to change, if possible.

If I use {N: 2} StringFormat / ConverterCulture, the TextBox is forced to have a decimal mark always (even during text input). I mean, you cannot delete a dot or comma at all, you should be able to figure out that you need to go to the next “field” of the number in order to edit the decimal points by clicking there or clicking “right”.

Since this non-initialist is for most users, is there a way to avoid this without resorting to rewriting formatters? I hope for something simple within the existing properties.

Example: a XAML text block is bound to a DataGrid cell,

<TextBox Name="TextBox1" Height="18" Margin="0,0,10,0" Text="{Binding SelectedItem[1], ConverterCulture=en-US, ElementName=Grid1, StringFormat={}{0:N2}, UpdateSourceTrigger=PropertyChanged}" Width="59" TextAlignment="Right" VerticalAlignment="Center" /> 

Added comments after replies:

• UpdateSourceTrigger = PropertyChanged seems to be directly related to this behavior.
• I suspect that a true complete solution may not be possible due to a logical conflict requiring both a true bi-directional update and a user trying to intervene with a new input at the same time.

Answer 1

The way the XAML event handler is installed explains that the TextBox1 control behavior: UpdateSourceTrigger=PropertyChanged sets the default behavior, which means that the source control ( TextBox1 ) is updated when the binding property changes. You can consider other TextBox events such as LostFocus and TextChanged , as shown below (C #):

 TextBox1.LostFocus += (s, e) => TextBox_LostFocus(s, e); TextBox1.TextChanged += (s, e) => TextBox_TextChanged(s, e); private void TextBox_LostFocus(object sender, RoutedEventArgs e) { // Your event handling procedure, Formatting, etc. } private void TextBox_TextChanged(object sender, RoutedEventArgs e) { // Your event handling procedure, Formatting, etc. } 

or using a simplified compact lambda-style syntax:

 TextBox1.LostFocus += (s, e) => {//Your procedure, Formatting, etc}; TextBox1.TextChanged += (s, e) => {//Your procedure, Formatting, etc}; 

The same could be declared in XAML, but I recommend implementing functionality in the code module.

Regarding your second question, namely: CultureInfo implementation: you can save the CultureInfo declaration in XAML or implement it in the code module by placing it in any of the above event handlers, for example (re: Changing the default and decimal separator in the binding of Andrey Gordeev ):

 String.Format(new CultureInfo("de-DE"), "{0:N}", valueTypeDouble); 

Hope this helps.