解析DateTime和时间（字符串）

Question

I am receiving an "Incorrect Format" error when trying to Parse a Date (DateTime) and a Time (string) together from two parts of a QueryString.

Any help appreciated in resolving this. Thanks!

var EventStartDate = Convert.ToDateTime(Request.QueryString["date"]);
string EventStartTime = Request.QueryString["time"];

DateTime newDateTime = 
  EventStartDate.Add(TimeSpan.ParseExact(EventStartTime, "H:mm:ss", null));

More detail below...

EventStartDate = 3/5/2016 12:00:00 AM

EventStartTime = 8:00:00 PM

Error:
Input string was not in a correct format.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.FormatException: Input string was not in a correct format.

Source Error: 
Line 8:          string EventStartTime = Request.QueryString["time"];
Line 9:  
Line 10:         DateTime newDateTime = EventStartDate.Add(TimeSpan.ParseExact(EventStartTime, "hh:mm:ss", null));

Answer 1

You have missed the HH . Please use HH instead of H . Hope it will work.

DateTime newDateTime = 
  EventStartDate.Add(TimeSpan.ParseExact(EventStartTime, "HH:mm:ss", null));

Answer 2

假设您的时间格式为00:00:00 ，请尝试此操作

DateTime newDateTime = EventStartDate.Add(TimeSpan.ParseExact(EventStartTime, "hh\\:mm\\:ss", null));

Answer 3

Convert.ToDateTime uses standard date and time format of your CurrentCulture settings. Looks like 3/5/2016 12:00:00 AM is not one of them. Also your CurrentCulture may have AMDesignator and PMDesignator properties as an empty strings.

You can use DateTime.ParseExact with a custom format and a specific culture setting like

var EventStartDate = DateTime.ParseExact(Request.QueryString["date"], 
                                         "M/d/yyyy hh:mm:ss tt",
                                         CultureInfo.InvariantCulture);

You said your EventStartTime is 8:00:00 PM and you try to parse it to TimeSpan but since a TimeSpan is a time interval, those designators have no meaning with them and they are not supported in as an input format as well.

If your string really have those designator, you need to remove them like;

string EventStartTime = Request.QueryString["time"].Replace("AM", "")
                                                   .Replace("PM", "").Trim();

then you can parse it to TimeSpan like;

var StartTime = TimeSpan.Parse(EventStartTime, CultureInfo.InvariantCulture);

as last, add it to your EventStartDate like;

var newDateTime = EventStartDate.Add(StartTime);