什么正则表达式将匹配文本,不包括HTML标记内的内容？

Question

我正在为搜索结果页面编写代码,需要突出显示搜索字词.这些术语碰巧发生在表格单元格中(应用程序正在迭代GridView行单元格),这些表格单元格可能包含HTML.

目前,我的代码看起来像这样(相关的帅哥如下所示):

const string highlightPattern = @"<span class=""Highlight"">$0</span>";
DataBoundLiteralControl litCustomerComments = (DataBoundLiteralControl)e.Row.Cells[CUSTOMERCOMMENTS_COLUMN].Controls[0];

// Turn "term1 term2" into "(term1|term2)"
string spaceDelimited = txtTextFilter.Text.Trim();
string pipeDelimited = string.Join("|", spaceDelimited.Split(new[] {" "}, StringSplitOptions.RemoveEmptyEntries));
string searchPattern = "(" + pipeDelimited + ")";

// Highlight search terms in Customer - Comments column
e.Row.Cells[CUSTOMERCOMMENTS_COLUMN].Text = Regex.Replace(litCustomerComments.Text, searchPattern, highlightPattern, RegexOptions.IgnoreCase);

令人惊讶的是它有效.但是,有时我匹配的文本是HTML,如下所示:

<span class="CustomerName">Fred</span> was a classy individual.

如果你搜索"类"我希望突出显示代码将"class"包装在"classy"中,但当然不是HTML属性"class"恰好在那里!如果您搜索"Fred",则应突出显示.

那么什么是一个好的正则表达式,以确保匹配只发生在html标签之外？它不一定是超级铁杆.我认为,只需确保匹配不在<和>之间就行了.

Answer 1

这个正则表达式应该完成这项任务:(?<!<[^>]*)(regex you want to check: Fred|span)它检查<[^>]*从匹配的字符串开始,不可能匹配正向后退的正则表达式.

修改后的代码:

const string notInsideBracketsRegex = @"(?<!<[^>]*)";
const string highlightPattern = @"<span class=""Highlight"">$0</span>";
DataBoundLiteralControl litCustomerComments = (DataBoundLiteralControl)e.Row.Cells[CUSTOMERCOMMENTS_COLUMN].Controls[0];

// Turn "term1 term2" into "(term1|term2)"
string spaceDelimited = txtTextFilter.Text.Trim();
string pipeDelimited = string.Join("|", spaceDelimited.Split(new[] {" "}, StringSplitOptions.RemoveEmptyEntries));
string searchPattern = "(" + pipeDelimited + ")";
searchPattern = notInsideBracketsRegex + searchPattern;

// Highlight search terms in Customer - Comments column
e.Row.Cells[CUSTOMERCOMMENTS_COLUMN].Text = Regex.Replace(litCustomerComments.Text, searchPattern, highlightPattern, RegexOptions.IgnoreCase);