Question

我编写了一个程序来对发件人的通用位置进行地理定位，但是我在从字符串中提取IP地址时遇到了问题，例如：

   public static string getBetween(string strSource, string strStart, string strEnd)
    {
        int Start, End;
        if (strSource.Contains(strStart) && strSource.Contains(strEnd))
        {
            Start = strSource.IndexOf(strStart, 0) + strStart.Length;
            End = strSource.IndexOf(strEnd, Start);
            return strSource.Substring(Start, End - Start);
        }
        else
        {
            return "";
        }

//我已将完整的EMAIL的MIME数据捕获到字符串（txtEmail） //现在我搜索字符串......

  //THIS IS MY PROBLEM. this is always different. 
  // I need to capture only the IP address between the brackets
  string findIP = "X-Originating-IP: [XXX.XXX.XXX.XXX]"; 
  string data = getBetween(findIP, "[", "]");
  txtCustomIPAddress.Text = data;

任何想法？

Answer 1

我建议使用正则表达式

Regex rex = new Regex("X-Originating-IP\\:\\s*\\[(.*)\\]", RegexOptions.Multiline|RegexOptions.Singleline);

string ipAddrText = string.Empty;
Match m = rex.Match(headersText);
if (m.Success){
    ipAddrText = m.Groups[1].Value;
}

// ipAddrText should contain the extracted IP address here

Working Demo Here

Answer 2

与Miky类似但使用positive lookahead/behind因此我们只选择IP地址。

var str = "X-Originating-IP: [XXX.XXX.XXX.XXX]";
var m = Regex.Match(str, @"(?<=X-Originating-IP:\ \[).*?(?=])");
var ipStr = m.Success ? m.Value : null;

在C＃中从电子邮件中捕获IP地址

2 个答案: