WPF richTextBox问题

Question

如果一行文本被包装到另一行,我如何以编程方式确定字符串中断点的位置.

示例:输入字符串="这是对包装的文本行的测试".

      Based on the width of the richTextBox it could display:


            This is a test of a wrapped line of
            text.

我需要确定的是被包裹的单词行中的偏移量.在上面的例子中,单词"文本".

当我从richTextBox中提取Xaml时,我得到原始文本解包.

谢谢,

鲍勃克林格

Answer 1

我发现的技巧使用 TextPointer 类及其 GetCharacterRec 方法。

RichTextBox 保存一个 FlowDocument。流文档中的文本包含在 Run 对象中（有点简化，但它有效）。该代码在第一次运行开始时找到 TextPointer。然后它获取第一个字符的边界矩形。接下来，代码一次向前移动一个字符，获取一个新的边界矩形，并检查新矩形的底部是否与原始矩形不同。如果底部不同，那么我们就在一条新线上。然后，TextPointer 可以获取中断之前或之后的文本。

public partial class Window1 : Window
{
    public Window1()
    {
        InitializeComponent();
    }

    private void inspect(object sender, RoutedEventArgs e)
    {
        TextPointer pointer = FindRun(inBox.Document);

        string textAfterBreak = FindBreak(pointer);

        outBox.Text = textAfterBreak;
    }

    private string FindBreak(TextPointer pointer)
    {
        Rect rectAtStart = pointer.GetCharacterRect(LogicalDirection.Forward);

        pointer = pointer.GetNextInsertionPosition(LogicalDirection.Forward);
        Rect currentRect = pointer.GetCharacterRect(LogicalDirection.Forward);

        while (currentRect.Bottom == rectAtStart.Bottom)
        {
            pointer = pointer.GetNextInsertionPosition(LogicalDirection.Forward);
            currentRect = pointer.GetCharacterRect(LogicalDirection.Forward);
        }

        string textBeforeBreak = pointer.GetTextInRun(LogicalDirection.Backward);
        string textAfterBreak = pointer.GetTextInRun(LogicalDirection.Forward);

        return textAfterBreak;
    }

    private TextPointer FindRun(FlowDocument document)
    {
        TextPointer position = document.ContentStart;

        while (position != null)
        {
            if (position.Parent is Run)
                break;

            position = position.GetNextContextPosition(LogicalDirection.Forward);
        }

        return position;
    }
}

<Window x:Class="LineBreaker.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
            <RowDefinition></RowDefinition>
        </Grid.RowDefinitions>
        <RichTextBox Grid.Row="0" Name="inBox">
        </RichTextBox>
        <Button Grid.Row="1" Click="inspect">Find Break</Button>
        <TextBox Name="outBox" Grid.Row="2"/>
    </Grid>
</Window>