Change Key in WPF KeyDown

Question

Legacy app conversion issue. VB6 TextBox_KeyDown() allows key to be changed (e.g. force keystroke to upper case but there are many other uses). How can this be done in WPF?

The only way I can see is too handle all TextBox keystrokes. In effect, reimplement TextBox editing. I'd rather not go there.

Answer 1

Very quick and dirty solution. Assuming you want to bind the TextBox.Text value to something, you could write a converter which simply calls ToUpper() on the string.

In the sample below the textbox is bound to itself. This is most likely NOT what you want in production, but it possible can inspire.

<local:UpperConverter x:Key="toUpperConverter" />

...

<TextBox Text="{Binding RelativeSource={RelativeSource Mode=Self},
                                Path=Text, Mode=OneWay, Converter={StaticResource toUpperConverter},
                                UpdateSourceTrigger=PropertyChanged}" />

...

class UpperConverter:IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return value.ToString().ToUpper();
        }