自定义TextBox用户控件在WPF中实现转换器

Question

I'm trying to build a Custom User Control , a custom TextBox to be exact. The idea is as the user types in the TextBox the text is converted to uppercase and displayed. But I cannot get it to work.

CustomTextBox UserControl:

<UserControl x:Class="SOFWpf.CustomTextBox"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
             xmlns:converters="clr-namespace:SOFWpf.Converters"
             mc:Ignorable="d" 
             d:DesignHeight="300" d:DesignWidth="300">
    <UserControl.Resources>
        <converters:CaseConverter x:Key="CaseConverter" />
    </UserControl.Resources>

    <TextBox Text="{Binding Path=., Converter={StaticResource CaseConverter}}"/>

UserControl's Code-Behind:

  public string Text
  {
     get { return (string)GetValue(TextProperty); }
     set { SetValue(TextProperty, value); }
  }

  public static readonly DependencyProperty TextProperty =
      DependencyProperty.Register("Text", typeof(string), typeof(CustomTextBox), new UIPropertyMetadata(""));

Usage:

<local:CustomTextBox Text="a b c"/>

Converter:

   public class CaseConverter : IValueConverter
   {
      public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
      {
         string text = value as string;

         return text?.ToUpper();
      }

      public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
      {
         string text = value as string;

         return text?.ToLower();
      }
   }

Answer 1

You need to add binding Path=Text:

<TextBox Text="{Binding Path=Text, Converter={StaticResource CaseConverter}}"/>

And in the user control constructor set DataContext to this:

public CustomTextBox()
{
    InitializeComponent();
    DataContext = this;
}