Proper case text as it is being entered in WPF

Question

How do I proper case text as the user enters it in a WPF form. I'm using the following code to do the proper casing which works fine, but I can't figure out how to do it on user entry.

Microsoft.VisualBasic.Strings.StrConv(txt.Text,VbStrConv.ProperCase,0);

Answer 1

        TextInfo txtinfo = Thread.CurrentThread.CurrentCulture.TextInfo;
        string titleCaseString = txtinfo.ToTitleCase(theString);

To work this in the DataBinding, you can write a WPF Binding Converter and add this logic there.

        <TextBox>
         <TextBox.Text>
            <Binding Path="ViewModelProperty" Converter="{StaticResource TitleCaseConverter}" UpdateSourceTrigger="PropertyChanged" />
         </TextBox.Text>
       </TextBox>

Answer 2

You'll want to use code like you have, or Jobi posted, in the Key_Down (or Up) event of the text control.

Answer 3

In our application we have a custom TextBox where we have overridden the PreviewTextInput event to perform validation there (we are validating the input against a regex and preventing the character from being added if it is invalid) - maybe you could do something similar?

I have had problems with custom TextBoxed before though, the caret jumping back to the start of the string was something I couldn't quite grasp either, can't remember how we got around it though.