实施搜索和突出显示 - 当突出显示速度缓慢时如何避免延迟? [英] Implementing search&highlight - how can I avoid delays when highlight is slow?
问题描述
我有一个 RichText,想实现一个高亮搜索,就像你在 VS 或 Chrome 中看到的那样.我得到了一个相当有效的实现:
I have a RichText, and want to implement a highlighting search, like you see in VS or Chrome. I got a fairly-working implementation going:
private void _txtSearch_TextChanged(object sender, EventArgs e)
{
new RichTextNode(richTextBox1).Highlight(_txtSearch.Text);
}
public void Highlight(string text)
{
textBox.BeginUpdate(); // Extension, implemented with P/Invoke
textBox.SelectionStart = 0;
textBox.SelectionLength = textBox.Text.Length;
textBox.SelectionBackColor = textBox.BackColor;
int highlights = 0;
if (!string.IsNullOrEmpty(text))
{
int pos = 0;
string boxText = textBox.Text;
while ((pos = boxText.IndexOf(text, pos, StringComparison.OrdinalIgnoreCase)) != -1 && (highlights++) < 500)
{
textBox.SelectionStart = pos;
textBox.SelectionLength = text.Length;
textBox.SelectionBackColor = Color.Yellow;
pos += text.Length;
}
}
textBox.EndUpdate(); // Extension, implemented with P/Invoke
}
但是,我想支持大量文本 - 最多 2MB.当有大量文本时,每次更新需要 250 毫秒.对于单次搜索来说没问题 - 但是,我的搜索是增量搜索,这意味着如果用户输入 10 个字母的作品,每个字母都会在 250 毫秒后出现,这看起来很糟糕.
However, I want to support large amounts of text - up to 2MB. When there's a lot of text, each such update takes 250ms. That's OK for a single search - however, my search is incremental, which means that if the user type a 10-letter work, each letter appears after 250ms, which looks bad.
我使用计时器实现了等待:
I implemented a wait using a timer:
private void _txtSearch_TextChanged(object sender, EventArgs e)
{
performSearch.Stop();
performSearch.Interval = 100; // Milliseconds
performSearch.Start();
}
private void performSearch_Tick(object sender, EventArgs e)
{
new RichTextNode(richTextBox1).Highlight(_txtSearch.Text);
performSearch.Stop();
}
这很有效.但是,当文本很短时,它会减慢增量搜索的速度,这是次优的.我想我可以计算字符数,但这感觉就像一个黑客......
This works fairly well. However, it slows down the incremental search when the text is short, which is sub-optimal. I guess I could count the chars, but that feels like a hack...
理想情况下,我不想在有额外的击键时突出显示:
Ideally, I'd like not to highlight when additional keystrokes are coming:
private void _txtSearch_TextChanged(object sender, EventArgs e)
{
if (!_txtSearch.Magic_are_additional_TextChanged_events_already_queued())
new RichTextNode(richTextBox1).Highlight(_txtSearch.Text);
}
有没有办法做到这一点?或者计时器解决方案是我所能希望的最好的解决方案吗?
Is there a way to do this? Or is the timer solution the best I can hope for?
推荐答案
我最终使用了问题中描述的计时器解决方案,延迟了 1 毫秒.
I ended up using the timer solution described in the question, with a delay of 1ms.
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