Automatically capitalize all input in WPF

I recommend creating a custom Textbox class and override an event to automatically capitalize the text. First, this depends on if you want the text to be capitalize as they type or after input is finished.

E.g. for after input is finished

public class AutoCapizalizeTextBox: TextBox
{
  public AutoCapitalizeTextBox()
  {
  }

  public AutoCapitlizeTextBox()
  {
  }

  protected override void OnLostFocus(EventArgs e)
  {
    this.Text = this.Text.ToUpper();

    base.OnLostFocus(e);
  }
}

If you want to capitalize the input for a single TextBox rather than all TextBoxes like above, you can use the following:

<TextBox CharacterCasing="Upper"/>

You can case all input into TextBox controls with the following property:

CharacterCasing="Upper"

To apply to all TextBox controls in the entire application create a style for all TextBox controls:

<Style TargetType="{x:Type TextBox}">
    <Setter Property="CharacterCasing" Value="Upper"/>
</Style>