多行文本框：在状态栏中显示当前行/字符索引

Posted 2023-04-18

【中文标题】多行文本框：在状态栏中显示当前行/字符索引

【英文标题】：Multiline Textbox : Display current line/character index in statusbar

【发布时间】：2011-10-15 18:27:49

【问题描述】：

我有一个多行文本框，用户可以在其中编辑文本。 在状态栏中，我想显示当前行/字符索引。 我知道我可以获取 CaretIndex，并使用 GetLineIndexFromCharacterIndex 来获取行索引。

但我将如何将其绑定到状态栏？

【问题讨论】：

嗨。同样的问题在这里。 ***.com/questions/8988539/…

【参考方案1】：

我会为此使用附加行为。该行为可以通过SelectionChanged 监听变化，并相应地更新两个附加属性CaretIndex 和LineIndex。

<TextBox Name="textBox"
         AcceptsReturn="True"
         local:CaretBehavior.ObserveCaret="True"/>

<TextBlock Text="Binding ElementName=textBox,
                          Path=(local:CaretBehavior.LineIndex)"/>
<TextBlock Text="Binding ElementName=textBox,
                          Path=(local:CaretBehavior.CaretIndex)"/>

CaretBehavior

public static class CaretBehavior 

    public static readonly DependencyProperty ObserveCaretProperty = 
        DependencyProperty.RegisterAttached 
        (
            "ObserveCaret",
            typeof(bool),
            typeof(CaretBehavior),
            new UIPropertyMetadata(false, OnObserveCaretPropertyChanged) 
        );
    public static bool GetObserveCaret(DependencyObject obj) 
    
        return (bool)obj.GetValue(ObserveCaretProperty); 
    
    public static void SetObserveCaret(DependencyObject obj, bool value) 
    
        obj.SetValue(ObserveCaretProperty, value); 
    
    private static void OnObserveCaretPropertyChanged(DependencyObject dpo, 
                                                   DependencyPropertyChangedEventArgs e) 
    
        TextBox textBox = dpo as TextBox;
        if (textBox != null) 
         
            if ((bool)e.NewValue == true) 
            
                textBox.SelectionChanged += textBox_SelectionChanged;
             
            else 
            
                textBox.SelectionChanged -= textBox_SelectionChanged; 
             
         
    

    static void textBox_SelectionChanged(object sender, RoutedEventArgs e)
    
        TextBox textBox = sender as TextBox;
        int caretIndex = textBox.CaretIndex;
        SetCaretIndex(textBox, caretIndex);
        SetLineIndex(textBox, textBox.GetLineIndexFromCharacterIndex(caretIndex));
    

    private static readonly DependencyProperty CaretIndexProperty =
        DependencyProperty.RegisterAttached("CaretIndex", typeof(int), typeof(CaretBehavior));
    public static void SetCaretIndex(DependencyObject element, int value)
    
        element.SetValue(CaretIndexProperty, value);
    
    public static int GetCaretIndex(DependencyObject element)
    
        return (int)element.GetValue(CaretIndexProperty);
    

    private static readonly DependencyProperty LineIndexProperty =
        DependencyProperty.RegisterAttached("LineIndex", typeof(int), typeof(CaretBehavior));
    public static void SetLineIndex(DependencyObject element, int value)
    
        element.SetValue(LineIndexProperty, value);
    
    public static int GetLineIndex(DependencyObject element)
    
        return (int)element.GetValue(LineIndexProperty);
    

【参考方案2】：

RichTextBox rtb = new RichTextBox();
int offset = 0;
rtb.CaretPosition.GetOffsetToPosition(rtb.Document.ContentStart);
rtb.CaretPosition.GetPositionAtOffset(offset).GetCharacterRect(LogicalDirection.Forward);

【参考方案3】：

恕我直言，最简单可靠的方法是使用 DispatcherTimer 对 CarteIndex 和 GetLineIndexFromCharacterIndex 成员进行采样。然后为状态栏绑定公开几个 DP 上的值。