隐藏/显示XAML元件或块LostFocus事件

Question

我有含有两个StackPanels，每个包含一个文本框和一个按钮的页面：

<StackPanel x:Name="Row1"> 
<TextBox x:Name="TextBox1" Text="" GotFocus="OnFocusHandler" LostFocus="OffFocusHandler"/> 
<Button x:Name="Button1" Content="Convert" Click="OnClickHandler" Visibility="Collapsed"/> 
</StackPanel> 

<StackPanel x:Name="Row2"> 
<TextBox x:Name="TextBox2" Text="" GotFocus="OnFocusHandler" LostFocus="OffFocusHandler"/> 
<Button x:Name="Button2" Content="Convert" Click="OnClickHandler" Visibility="Collapsed"/> 
</StackPanel> 

我想执行以下操作：

• 当一个文本框具有焦点，另一个文本框必须隐藏并且相应的按钮必须显示
• 当文本框不在焦点时，我们回到原始显示：只有空的文本框可见
• 我不想让按钮能够触发OffFocusHandler

这是当前的代码，我有三个处理程序：

private void OnFocusHandler(object sender, RoutedEventArgs e) 
{ 
    TextBox SenderTextBox = (TextBox)sender; 

    if (SenderPanel.Name == "TextBox1") 
    { 
     Button1.Visibility = Visibility.Visible; 
    } 
    else if (SenderPanel.Name == "TextBox2") 
    { 
     Button2.Visibility = Visibility.Visible; 
    } 
} 

private void OffFocusHandler(object sender, RoutedEventArgs e) 
{ 
    TextBox1.Text = ""; 
    TextBox2.Text = ""; 
    Button1.Visibility = Visibility.Collapsed; 
    Button2.Visibility = Visibility.Collapsed; 
} 

private void OnClickHandler(object sender, RoutedEventArgs e) 
{ 
    // some stuff unrelated to my issue 
} 

如何避免点击按钮来触发代码是OffFocusHandler？ 有没有另外一种方法来编码？我是一个完整的初学者，所以我可能不会认为正确的方法。

Answer 1

您可以将其绑定到Xaml中的TextBox.IsFocused属性，并使用BooleanToVisibilityConverter来显示/隐藏该按钮。

实施例：

<Window x:Class="WpfApplication4.MainWindow" 
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
     xmlns:local="clr-namespace:WpfApplication4" 
     Title="MainWindow" Height="300" Width="400" Name="UI" > 
    <Window.Resources> 
     <BooleanToVisibilityConverter x:Key="BoolTovisible" /> 
    </Window.Resources> 

    <Grid> 
     <StackPanel x:Name="Row1" Height="54" VerticalAlignment="Top"> 
      <TextBox x:Name="TextBox1" Text="" /> 
      <Button x:Name="Button1" Content="Convert" Visibility="{Binding ElementName=TextBox1, Path=IsFocused, Converter={StaticResource BoolTovisible}}"/> 
     </StackPanel> 

     <StackPanel x:Name="Row2" Margin="0,60,0,0" Height="51" VerticalAlignment="Top"> 
      <TextBox x:Name="TextBox2" Text="" /> 
      <Button x:Name="Button2" Content="Convert" Visibility="{Binding ElementName=TextBox2, Path=IsFocused, Converter={StaticResource BoolTovisible}}"/> 
     </StackPanel> 
    </Grid> 
</Window>