Question

我正在尝试构建一个自定义用户控件，一个自定义TextBox。这个想法就是用户在TextBox中键入文本转换为大写并显示。但我无法让它发挥作用。

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的代码隐藏：

  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(""));

用法：

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

转换器：

   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

您需要添加绑定Path = Text：

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

在用户控件构造函数中将DataContext设置为：

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

自定义TextBox用户控件在WPF中实现转换器

1 个答案: