验证时区字符串并将其作为分钟返回

我觉得很好。我只想说出这些小组的名字(为了清楚起见):

Match tzre = new Regex(@"^(?<sign>\+|-)?(?<hour>0?[0-9]|1[0-2])(?<mins>00|15|30|45)$").Match(tz);

也许可以将您的转换改为:

tz = (tzg["sign"].Value == "+" || tzg["sign"].Value == "" ? 1 : -1) 
    * int.Parse(tzg["hour"].Value) * 60 
    + int.Parse(tzg["mins"])

尝试将不同的组设置为

new TimeSpan(h, m, 0).TotalMinutes();

string tz = userList.Rows[0][1].ToString().Trim();
//Timezones can take the form of + or - followed by hour and then minutes in 15 minute increments.
Match tzre = new Regex(@"^(\+|-)?(0?[0-9]|1[0-2])(00|15|30|45)$").Match(tz);
if (!tzre.Success)
{
    throw new
        myException("Row 1, column 2 of the CSV file to be imported must be a valid timezone: " + tz);
}
GroupCollection tzg = tzre.Groups;
tz = (new TimeSpan(int.Parse(tzg[1].Value + tzg[2].Value), int.Parse(tzg[3].Value), 0).TotalMinutes).ToString();