C# - System.FormatException类型的未处理异常 - List List to List int

Question

我收到错误"FormatException未处理" - 就此:

           List<int> myStringList = LoadHours.ConvertAll(s => Int32.Parse(s));

我需要能够进行加法和除法,这就是为什么我试图将它们转换为整数.所以我不知道如何处理这个,我需要将它们转换回字符串吗？

代码:

           //string txt = "Account: xxx123xxx\r\nAppID 10: 55 Hours 4 Minutes\r\n\r\nAccount: xxx124xxx\r\nAppID 730: 62 Hours 46 Minutes\r\nAppID 10: 3 Hours 11 Minutes\r\n\r\nAccount: xxx125xxx\r\nAppID 10: 0 Hours 31 Minutes\r\n";
           string path = @"Hours.txt";
           string text = File.ReadAllText(@"Hours.txt");
           Regex pattern = new Regex(@"^((AppID (?<appid>\d+): ((?<hours>\d+) Hours )?((?<minutes>\d+) Minutes)?)|(Account: (?<account>xxx\d+xxx)))", RegexOptions.Multiline);

           string[] lines = File.ReadAllLines(path);

           int HrElapsed;
           int MinElapsed;

           Int32.TryParse(HoursElapsed(), out HrElapsed);
           Int32.TryParse(MinutesElapsed(), out MinElapsed);

           List < string > LoadHours = new List < string > ();
           List < string > LoadMinutes = new List < string > ();

           // Iterate through lines
           foreach(string line in lines) {
            //Check if line matches your format here
            Match match = pattern.Match(line);
            LoadHours.Add(match.Groups["hours"].Value);
            LoadMinutes.Add(match.Groups["minutes"].Value);
            //File.WriteAllText(@"Hours.txt", Regex.Replace(File.ReadAllText(@"Hours.txt"), @"AppID \d+:\s(\d+\s\w+\s\d+\s\w+)",LogTime));
           }
           List < int > myStringList = LoadHours.ConvertAll(s => Int32.Parse(s));
           List < int > myStringList2 = LoadMinutes.ConvertAll(s => Int32.Parse(s));

           for (int i = 0; i < myStringList.Count; ++i)

            {
            myStringList[i] = myStringList[i] + HrElapsed;
           }

           for (int i = 0; i < myStringList2.Count; ++i) {
            myStringList2[i] = myStringList2[i] + MinElapsed;
           }

           string[] the_array = myStringList.Select(i => i.ToString()).ToArray();
           string[] the_array2 = myStringList2.Select(i => i.ToString()).ToArray();

           Regex re = new Regex(@"^((AppID (?<appid>\d+): ((?<hours>\d+) Hours )?((?<minutes>\d+) Minutes)?)|(Account: (?<account>xxx\d+xxx)))", RegexOptions.Multiline);
           string hackount = "";
           (from m in re.Matches(text).Cast < Match > ()

            let acc = m.Groups["account"].Value
            let app = m.Groups["appid"].Value
           // let hrs = m.Groups["hours"].Value
           // let mins = m.Groups["minutes"].Value
           let timHours = the_array
            let timMinutes = the_array2
            let obj = new {
            Account = acc == "" ? hackount : (hackount = acc), AppId = app, Time = the_array, the_array2
           }
           where app != ""
           select obj

           ).ToList().ForEach(Console.WriteLine);

Hours.txt文件包括:

Account: xxx123xxx
AppID 10: 1 Hours 5 Minutes

Account: xxx124xxx
AppID 10: 2 Hours 6 Minutes
AppID 10: 3 Hours 7 Minutes

Account: xxx125xxx
AppID 10: 4 Hours 8 Minutes

我只是想修改小时和分钟的数字.计算经过的时间(程序打开的时间长度)并将其添加到已存储在文本文件中的金额.然后将其保存回文件,而不是将其输出到控制台.(我解析文件并使用正则表达式来抓取数字,我想我需要做的是如果语句分钟> 60转换类似于此afaik):

                    int TotalHours = HrElapsed + HrStored;
                    int TotalMinutes = MinElapsed + MinStored;

                    // Just making sure the minutes don't end up as "141 minutes" so it's incrementing hours. 
                    if (TotalMinutes >= 60)
                    {
                        int remainder = TotalMinutes % 60;
                        int whole = TotalMinutes / 60;
                        TotalMinutes = remainder;
                        TotalHours = TotalHours + whole;
                    }

Answer 1

这是因为您忘记检查正则表达式匹配是否成功。

if (match.Success) // You need this check 
{
     LoadHours.Add(match.Groups["hours"].Value);
     LoadMinutes.Add(match.Groups["minutes"].Value);
}

实际上match.Groups["hours"].Value当匹配失败时只会返回一个空字符串。随后Int32.Parse(String.Empty)会抛出一个FormatException

一个简单的测试：

 Regex pattern = new Regex(@"(?<hours>\d+)d");
 Match match = pattern.Match("Textwithoutdigits");
 var value = match.Groups["hours"].Value;
 Console.WriteLine(value == String.Empty); // <-- Will print true