WPF 流文档“更改案例”功能
本文关键字:案例 更改案例 功能 文档 WPF | 更新日期: 2023-09-27 18:32:51
我正在为我的RichTextBox实现"更改大小写"功能,就像单词在Shift+F3中一样。它所做的只是在下标题>大>标题大小写之间切换,一旦我可以访问我需要的字符串,这非常简单。
我的问题是,如何在流文档中更改(并首先找到它)一个字符串,而不会丢失可能包含在字符串中的任何嵌入元素(丢失格式不是问题)。与单词相同,我需要此功能用于 2 种情况:
1) 鼠标选择的文本。我试过简单
this.Selection.Text = newText;
但这当然丢失了我的嵌入元素。
2)插入符号位置前的最后一个单词。任何非文本元素都是单词分隔符,但是一个单词可以是
"He<weird formatting begin>ll<weird formatting end>o".
解决方案
通过这种方式,它模仿MS WORD Shift+F3行为。在极少数情况下发生的唯一问题是 carret 被移动到单词开头而不是保持其位置。我想在 EditCommand.MoveLeftByWord.Execute(null, this) 之后短暂的睡眠;会解决这个问题,但这将是一个肮脏的黑客,我正在努力找出一个更好的解决方案。
private void ChangeCase()
{
try
{
TextPointer start;
TextPointer end;
FindSelectedRange(out start, out end);
List<TextRange> textToChange = SplitToTextRanges(start, end);
ChangeCaseToAllRanges(textToChange);
}
catch (Exception ex)
{
mLog.Error("Change case error", ex);
}
}
private void FindSelectedRange(out TextPointer start, out TextPointer end)
{
if (!this.Selection.IsEmpty)
{
start = this.Selection.Start;
end = this.Selection.End;
}
else
{
end = this.CaretPosition;
EditingCommands.MoveLeftByWord.Execute(null, this);
start = this.CaretPosition;
this.CaretPosition = end;
}
}
private static List<TextRange> SplitToTextRanges(TextPointer start, TextPointer end)
{
List<TextRange> textToChange = new List<TextRange>();
var previousPointer = start;
for (var pointer = start; pointer.CompareTo(end) <= 0; pointer = pointer.GetPositionAtOffset(1, LogicalDirection.Forward))
{
var contextAfter = pointer.GetPointerContext(LogicalDirection.Forward);
var contextBefore = pointer.GetPointerContext(LogicalDirection.Backward);
if (contextBefore != TextPointerContext.Text && contextAfter == TextPointerContext.Text)
{
previousPointer = pointer;
}
if (contextBefore == TextPointerContext.Text && contextAfter != TextPointerContext.Text && previousPointer != pointer)
{
textToChange.Add(new TextRange(previousPointer, pointer));
previousPointer = null;
}
}
textToChange.Add(new TextRange(previousPointer ?? end, end));
return textToChange;
}
private void ChangeCaseToAllRanges(List<TextRange> textToChange)
{
var textInfo = (mCasingCulture ?? CultureInfo.CurrentUICulture).TextInfo;
var allText = String.Join(" ", textToChange.Select(x => x.Text).Where(x => !string.IsNullOrWhiteSpace(x)));
Func<string, string> caseChanger = GetConvertorToNextState(textInfo, allText);
foreach (var range in textToChange)
{
if (!range.IsEmpty && !string.IsNullOrWhiteSpace(range.Text))
{
range.Text = caseChanger(range.Text);
}
}
}
private static Func<string, string> GetConvertorToNextState(TextInfo textInfo, string allText)
{
Func<string, string> caseChanger;
if (textInfo.ToLower(allText) == allText)
{
caseChanger = (text) => textInfo.ToTitleCase(text);
}
else if (textInfo.ToTitleCase(textInfo.ToLower(allText)) == allText)
{
caseChanger = (text) => textInfo.ToUpper(text);
}
else
{
caseChanger = (text) => textInfo.ToLower(text);
}
return caseChanger;
}