c# - 如何检查文本中是否包含 "not allowed"单词或符号？

Question

假设我有一个包含允许的符号和单词的列表，如下所示:

+ - TEXT \s

有效字符串是不包含其他符号或单词的字符串。

例如，以下是有效的字符串:

TEXT + TEXT
TEXT - TEXT

以下不是:

NUMBER + TEXT
TEXT / TEXT

我需要一些帮助来构建可用于应用此类验证的正则表达式。我的问题是我无法将符号与正则表达式中的单词组合起来。

例如，当验证符号时，上面的代码工作正常:

(?n)[^\s\+-] # it is matching everything that is not a "space", "+" or "-"

但是如果我尝试添加一个词，表达式匹配它的字符，而不是词本身:

(?n)[^\s\+-\bTEXT\b]

我尝试了不同的正则表达式(用|、() 分隔参数)但失败了。

谁能告诉谁来解决这个问题？

Answer 1

您可以依赖Replace。示例代码:

string input = "TEXT+TEXT";
List<string> allAllowed = new List<string>() { "+", "-", "TEXT", @"\s" };

//In case of having allowed words sharing common parts (e.g., TEXT & SUBTEXT), 
//you would have to order the list by word-length to avoid problems
//allAllowed = allAllowed.OrderByDescending(x => x.Length).ToList();

string outString = input;
foreach (string allowed in allAllowed)
{
    outString = outString.Replace(allowed, "").Trim();

    //As suggested by Erresen via comments I am including Trim() 
    //because in the provided samples the blank spaces are not invalid characters.
}

bool inputIsValid = (outString == "");