完成触发从WPF中的文本框中的事件的作业

Question

您好我想把我正在做的事情从代码后面在正在应用在文本框中的样式的触发器中。我想要的是防止使用代码隐藏来做到这一点，并使用触发器。有什么办法可以做到这一点？

我的文本框

<TextBox Name="myTextBox" Style="{StaticResource txtBoxStyle}"/> 

我的风格

<Style x:Key="txtBoxStyle" TargetType="{x:Type TextBox}"> 
    <Setter Property="Foreground" Value="Silver"/> 
    <Setter Property="MaxLength" Value="6"/> 
</Style> 

从代码的活动

private void myTextBox_LostFocus(object sender, RoutedEventArgs e) 
{ 
    if (myTextBox.Text.Length == 0) 
     myTextBox.Text = "000000"; 
} 

private void myTextBox_GotFocus(object sender, RoutedEventArgs e) 
{ 
    if (myTextBox.Text == "000000") 
     myTextBox.Clear(); 
} 

private void myTextBox_PreviewKeyDown(object sender, KeyEventArgs e) 
{ 
    if (!(e.Key >= Key.D0 && e.Key <= Key.D9) && e.Key != Key.Back) 
     e.Handled = true; 
} 

private void myTextBox_TextChanged(object sender, TextChangedEventArgs e) 
{ 
    if (myTextBox.Text == "000000") 
     myTextBox.Foreground = Brushes.Silver; 
    else 
    {     
     myTextBox.Foreground = Brushes.Black; 

     if(myTextBox.Text.Length == 6) 
      myButton.Visibility = Visibility.Visible; 
     else 
      myButton.Visibility = Visibility.Hidden; 
    } 
} 

背后感谢提前！

Answer 1

编辑：对这个逻辑使用触发器不是一个好主意，并且由于其自引用（导致堆栈溢出）很可能失败，值转换器也有点问题。要封装复杂的逻辑并通过Style应用，请使用attached behavior。

---

<Style TargetType="{x:Type TextBox}"> 
    <Style.Triggers> 
     <MultiDataTrigger> 
      <MultiDataTrigger.Conditions> 
       <Condition Binding="{Binding IsFocused, RelativeSource={RelativeSource Self}}" Value="False"/> 
       <Condition Binding="{Binding Text, RelativeSource={RelativeSource Self}}" Value=""/> 
      </MultiDataTrigger.Conditions> 
      <MultiDataTrigger.Setters> 
       <Setter Property="Text" Value="000000"/> 
      </MultiDataTrigger.Setters> 
     </MultiDataTrigger> 
     <MultiDataTrigger> 
      <MultiDataTrigger.Conditions> 
       <Condition Binding="{Binding IsFocused, RelativeSource={RelativeSource Self}}" Value="True"/> 
       <Condition Binding="{Binding Text, RelativeSource={RelativeSource Self}}" Value="000000"/> 
      </MultiDataTrigger.Conditions> 
      <MultiDataTrigger.Setters> 
       <Setter Property="Text" Value=""/> 
      </MultiDataTrigger.Setters> 
     </MultiDataTrigger> 
     <Trigger Property="Text" Value="000000"> 
      <Setter Property="Foreground" Value="Silver"/> 
     </Trigger> 
    </Style.Triggers> 
    <!-- If (Text != "000000") Foreground = Brushes.Black --> 
    <Setter Property="Foreground" Value="Black"/> 
</Style> 

其设置按钮的可见性不应该在这种风格，但通过按钮来处理逻辑。键盘事件不能被翻译。

按钮风格：

<Style TargetType="{x:Type Button}"> 
    <Setter Property="Visibility" Value="Hidden"/> <!-- Normal state --> 
    <Style.Triggers> 
     <DataTrigger Binding="{Binding Text.Length, ElementName=myButton}" Value="6"> 
      <Setter Property="Visibility" Value="Visible"/> 
     </DataTrigger> 
    </Style.Triggers> 
</Style>