无法将字符串转换为DateTime

Question

I want to get a max date from the List<>.

But I don't know how to convert x.time to DateTime.

It always show error like this in exception: String was not recognized as a valid DateTime .

Here my code to do this:

List<DTOSaveFromFile> lst = Load();

public static List<DTOSaveFromFile> Load()
{
   string[] data = File.ReadAllLines(dataPath);
   return (from i in data select new DTOSaveFromFile(i)).ToList<DTOSaveFromFile>();
}

foreach (var rows in lst)
{
    DateTime biggest = lst
        Select(x => DateTime.ParseExact(x.time, "d/M/yyyy", System.Globalization.CultureInfo.InvariantCulture)) //to get the list of `string` of `time` from your List<DTOSaveFromFile> + //To convert it to DateTime 
        .Max(); //Get the max among the DateTime
}

x.time from class:

public class DTOSaveFromFile
{
    public string reportName { get; set; }
    public string eMail { get; set; }
    public string time { get; set; }
}

How to resolve this problem? Thanks.

Answer 1

Add the format for your DateTime.ParseExact to handle that 05-01-2016 case

string[] formats = new string[] {"d/M/yyyy", "d-M-yyyy"}; //notice the dash

Then your query would be like:

string[] formats = new string[] {"d/M/yyyy", "d-M-yyyy"}; //notice the dash
DateTime biggest = lst
        .Select(x => DateTime.ParseExact(x.time, formats, //now use formats here
                    System.Globalization.CultureInfo.InvariantCulture, 
                    System.Globalization.DateTimeStyles.AssumeLocal)) //to get the list of `string` of `time` from your List<DTOSaveFromFile> + //To convert it to DateTime 
        .Max(); //Get the max among the DateTime

Note that there is additional parameters you may need to all in your DateTime.ParseExact , which is System.Globalization.DateTimeStyles.AssumeLocal .

Also, whenever you find an error due to new format , just add that format in the formats array