c# - 无法解决“字符串未被识别为有效的日期时间问题”c#

Question

我的程序运行良好，现在我已经开始接收

String was not recognized as a valid DateTime.

我似乎无法解决的错误。我已经到处寻找解决方案，但没有解决问题。任何建议将不胜感激。

public Form1()
{
    InitializeComponent();

    DirectoryInfo dir = new DirectoryInfo(@"../Debug/");
    FileInfo[] files = dir.GetFiles("*.txt");

    Dictionary<FileInfo, DateTime> filesWithDueDate = new Dictionary<FileInfo, DateTime>();

    foreach (FileInfo file in files)
    {
        string dueDate = File.ReadAllText(file.FullName);

        Regex regex = new Regex(@"\d{2}/\d{2}/\d{4}");
        Match mat = regex.Match(dueDate);

        // Error happens here //
        DateTime duedate = Convert.ToDateTime(mat.ToString());

        filesWithDueDate.Add(file, duedate);
    }

    var sortedFiles = filesWithDueDate.OrderBy(a => a.Value).Select(b => b.Key.Name).ToArray();

    listBox1.Items.AddRange(sortedFiles);
}

Answer 1

你应该使用 TryParse 模式并在它失败时抛出一个好的异常

DateTime dateValue;
bool tryParseAttempt = DateTime.TryParse(mat.ToString(), out dateValue);
if(!tryParseAttempt)
{
    throw new ArgumentException(string.Format("Cannot parse value to DateTime.  '{0}'", mat.ToString());
}

参见 https://msdn.microsoft.com/en-us/library/ch92fbc1(v=vs.110).aspx