我现在已经使用了太长时间，试图找出一个问题，我认为这不会那么难。
这是交易：
我正在使用 C# 和 WPF 编写一个小型应用程序。
我有一个包含 FlowDocument 的 RichTextBox。
我在我的richtextbox 下方添加了一个小文本框和一个按钮。
然后用户输入他/她希望搜索的词，并按下按钮。
然后，richtextbox 将跳转到该单词的第一次出现。
只要它跳到正确的行就足够了——它还可以通过单词选择、突出显示或放置光标——只要richTextBox滚动到单词，任何事情都可以。
继续按下按钮，将跳转到下一个出现的单词，依此类推，直到文档结束。
正如我所说 - 我认为这是一项简单的任务 - 但是我在解决这个问题时遇到了严重的问题。
这应该做的工作：
public bool DoSearch(RichTextBox richTextBox, string searchText, bool searchNext)
{
TextRange searchRange;
// Get the range to search
if(searchNext)
searchRange = new TextRange(
richTextBox.Selection.Start.GetPositionAtOffset(1),
richTextBox.Document.ContentEnd);
else
searchRange = new TextRange(
richTextBox.Document.ContentStart,
richTextBox.Document.ContentEnd);
// Do the search
TextRange foundRange = FindTextInRange(searchRange, searchText);
if(foundRange==null)
return false;
// Select the found range
richTextBox.Selection.Select(foundRange.Start, foundRange.End);
return true;
}
public TextRange FindTextInRange(TextRange searchRange, string searchText)
{
// Search the text with IndexOf
int offset = searchRange.Text.IndexOf(searchText);
if(offset<0)
return null; // Not found
// Try to select the text as a contiguous range
for(TextPointer start = searchRange.Start.GetPositionAtOffset(offset); start != searchRange.End; start = start.GetPositionAtOffset(1))
{
TextRange result = new TextRange(start, start.GetPositionAtOffset(searchText.Length);
if(result.Text == searchText)
return result;
}
return null;
}
FindTextInRange 中 for() 循环的原因不幸的是 range.Text 会去除非文本字符，因此在某些情况下 IndexOf 计算的偏移量会略低。
我使用了不同的方法。使用文本框设置关键字；这在按钮单击时搜索关键字。找到关键字；突出显示它并专注于该关键字。
// Index of Current Result Found (Counts Characters not Lines or Results)
private int IndexOfSearchResultFound;
// Start Position Index of RichTextBox (Initiated as 0 : Beggining of Text / 1st Char)
private int StartOfSelectedKeyword;
private int EndOfSelectedKeyword;
private void btnSearch_Click(object sender, EventArgs e)
{
// Reset Keyword Selection Index. (0 is the Staring Point of the Keyword Selection)
IndexOfSearchResultFound = 0;
// Specify the End of the Selected Keyword; using txt_Search.Text.Lenght (Char Ammount).
EndOfSelectedKeyword = txt_Search.Text.Length;
// If txt_Search.Text is not Empty
if (txt_Search.Text.Length > 0)
{
// Find Keyword in RichTextBox.Text
IndexOfSearchResultFound = FindKeyword(txt_Search.Text.Trim(), StartOfSelectedKeyword, rtb_Hosts.Text.Length);
// If string was found in RichTextBox; Highlight it and Focus on Keyword Found Location
if (IndexOfSearchResultFound >= 0)
{
// Focus on Currently Found Result
rtb_Hosts.Focus();
// Highlight the search string
rtb_Hosts.Select(IndexOfSearchResultFound, EndOfSelectedKeyword);
// Sets a new Starting Position (after the Position of the Last Result Found)
// To be Ready to Focus on the Next Result
StartOfSelectedKeyword = IndexOfSearchResultFound + EndOfSelectedKeyword;
}
}
}
private int FindKeyword(string _SearchKeyword, int _KeywordSelectionStart, int _KeywordSelectionEnd)
{
// De-Select Previous Searched String (Keyword)
if (_KeywordSelectionStart > 0 && _KeywordSelectionEnd > 0 && IndexOfSearchResultFound >= 0)
{ rtb_Hosts.Undo(); }
// Set the return value to -1 by default.
int retVal = -1;
// A valid Starting index should be specified.
// if indexOfSearchText = -1, Means that Search has reached the end of Document
if (_KeywordSelectionStart >= 0 && IndexOfSearchResultFound >= 0)
{
// Find Keyword
IndexOfSearchResultFound = rtb_Hosts.Find(_SearchKeyword, _KeywordSelectionStart, _KeywordSelectionEnd, RichTextBoxFinds.None);
// Determine whether the text was found in richTextBox
retVal = IndexOfSearchResultFound;
}
// Return the index to the specified Keyword text.
return retVal;
}
我唯一无法实现的是返回到第一个搜索结果
这是一个变体，它将找到最接近插入符号位置的匹配项。
private TextRange FindText(string findText)
{
var fullText = DoGetAllText();
if (string.IsNullOrEmpty(findText) || string.IsNullOrEmpty(fullText) || findText.Length > fullText.Length)
return null;
var textbox = GetTextbox();
var leftPos = textbox.CaretPosition;
var rightPos = textbox.CaretPosition;
while (true)
{
var previous = leftPos.GetNextInsertionPosition(LogicalDirection.Backward);
var next = rightPos.GetNextInsertionPosition(LogicalDirection.Forward);
if (previous == null && next == null)
return null; //can no longer move outward in either direction and text wasn't found
if (previous != null)
leftPos = previous;
if (next != null)
rightPos = next;
var range = new TextRange(leftPos, rightPos);
var offset = range.Text.IndexOf(findText, StringComparison.InvariantCultureIgnoreCase);
if (offset < 0)
continue; //text not found, continue to move outward
//rtf has broken text indexes that often come up too low due to not considering hidden chars. Increment up until we find the real position
var findTextLower = findText.ToLower();
var endOfDoc = textbox.Document.ContentEnd.GetNextInsertionPosition(LogicalDirection.Backward);
for (var start = range.Start.GetPositionAtOffset(offset); start != endOfDoc; start = start.GetPositionAtOffset(1))
{
var result = new TextRange(start, start.GetPositionAtOffset(findText.Length));
if (result.Text?.ToLower() == findTextLower)
{
return result;
}
}
}
}
如果您想突出显示匹配项，那么只需将此方法更改为 void 并在找到匹配项时执行此操作：
textbox.Selection.Select(result.Start, result.End);