由网友(楛囗)分享简介：我有一个foreach语句正在搜索名单，其中在一个字符串值;字符串＆GT; 。如果当前行被读取包含字符串，我想取代它，但有一些注意事项。I have a foreach statement that is searching for a string value within a List. If t...

我有一个foreach语句正在搜索名单，其中在一个字符串值;字符串＆GT; 。如果当前行被读取包含字符串，我想取代它，但有一些注意事项。

I have a foreach statement that is searching for a string value within a List<string>. If the current line being read contains the string, I want to replace it, but with certain caveats.

foreach (string shorthandValue in shorthandFound)
{
    if (currentLine.Contains(shorthandValue))
    {
        // This method creates the new string that will replace the old one.
        string replaceText = CreateReplaceString(shorthandValue);
        string pattern = @"(?<!_)" + shorthandValue;
        Regex.Replace(currentLine, pattern, replaceText);
        // currentline is the line being read by the StreamReader.
     }
}

我试图让系统忽略的字符串，如果一个下划线（ pceded的 shorthandValue 是$ P $_ ）。否则，我希望它被替换（即使它是在该行的开始）。

I'm trying to get the system to ignore the string if the shorthandValue is preceded by an underscore character ("_"). Otherwise, I want it to be replaced (even if it is at the start of the line).

我是谁不这样做是否正确？

What am I not doing correctly?

更新

这是主要工作正常：

Regex.Replace(currentFile, "[^_]" + Regex.Escape(shorthandValue), replaceText);

然而，虽然它并忽略下划线，它它除去shorthandValue串之前的任何空间。因此，如果该行读取。这是一个test123，和test123被替换，我结束了这样的结果：

However, while it does ignore the underscore, it it removing any space before the shorthandValue string. So if the line read "This is a test123.", and the "test123" is replaced, I end up with this result:

这是aVALUEOFTHESHORTHAND。

"This is aVALUEOFTHESHORTHAND."

为什么空间被删除？

再次更新

我改变了正则表达式回到我的。（小于？！_），这是preserving空格

I changed the regex back to my (?<!_) and it is preserving the spaces.

推荐答案

您正则表达式是正确的。的问题是，Regex.Replace返回一个新字符串

Your regex is correct. The problem is that Regex.Replace returns a new string.

正在忽略了返回的字符串。

You are ignoring the returned string.