Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 7 years ago.
Improve this question
I searched in SO, but was not able to find responses that would work for me.
I have a dateTime value in c# and I would like to check if its got a valid value .For example if the following value is passed to datetimeupdate(which is of type datetime) I should be able to throw an exception .
datetimeupdate= 2015-07-29T19:55:10.994sdfsdf
I tried using Tryparse but it accepts string as the first parameter. But the datetimeupdate parameter is of type datetime. I am not sure how to check if the parameter has valid value.
I cannot do front end validition as this is in WebAPI and thats the value I get(with invalid characters)
What you have a string representation of a datetime. You can use TryParse() method like below; which will return TRUE if parsing succeeds.
static void Main(string[] args)
{
string str = "2015-07-29T19:55:10.994sdfsdf";
Console.WriteLine(IsvalidDateTime(str));
}
static bool IsvalidDateTime(string date)
{
DateTime dt;
return DateTime.TryParse(date, out dt);
}
using System;
public class Program
{
public static void Main()
{
try
{
string d = "2015-07-29T19:55:10.994sdfsdf";
DateTime dt = Convert.ToDateTime(d);
Console.WriteLine(dt);
}
catch(FormatException)
{
Console.WriteLine(" Date is InValid ");
}
}
}
DateTime formats quite extensively between different countries/regions.
For instance here in Sweden we follow the ISO 8601-format — yyyy-MM-dd. In the US, the standard format is M/d yyyy
So as for a the "validity" of a date; it's hard to say.
One might describe the date as 2015-07-29T19:55:10.994sdfsdf.
And it could be valid if your program could handle (and parse) that input.
The easiest solution to your problem is to use DateTime.Parse or DateTime.TryParseExact (if you know what format your date is in)
string dateString = "2015-07-30 18:00:00.142"
string dateFormat = "yyyy-MM-dd HH:mm:ss.fff"
DateTime parsedDate;
bool parseSuccess = DateTime.TryParseExact(
s: dateString,
format: dateFormat,
provider: CultureInfo.CurrentCulture,
style: DateTimeStyles.None,
result: out parsedDate
);
if (parseSuccess)
{
// valid
}
else
{
// not valid
}
If the format of the string-representation of the DateTime is unknown, you may use DateTime.Parse or DateTime.TryParse.
string dateString = "2015-07-30 18:00:00.142"
DateTime parsedDate;
if (DateTime.TryParse(dateString, out parsedDate))
{
// valid
}
else
{
// not valid
}
However, even though used quite extensively — these come with no guarantee of parsing a "correct" date, since the end-user might have entered the date in a different format than expected. And you might end up with the hours in place of the months; which could have some quite unexpected consequences.
Some reading
Custom DateTime-formats.
DateTime.TryParse
DateTime.TryParseExact
Related
When giving "12-5" or "12,5" as an input to DateTime.TryParse in .NET, it is converting it to "12-05-2020" and the return value is true. How is "12-5" equal to "12-05-2020"? In my case, the input string is the user's date of birth and it is a free text as per the requirement and the parsed value "12-05-2020" makes no sense as the date of birth cant be a future date. Is there a way to correct this without using DateTime.Parse or DateTime.ParseExact as they might throw exceptions.
Well, you have 2 tests to perform:
For a valid date syntax (say, bla-bla-bla is not one)
For a valid date value (say, 25-03-2123 is not one)
Let's check for these requirements in one if:
string userInput = "12-05-15"; // 12 May 2015
...
// We can use several formats in one go:
// DateTime.TryParseExact will try formats in the given order
string[] allowedFormats = new string[] {
"d-M-yy", "d-M-yyyy", "MMM d yyyy",
};
if (DateTime.TryParseExact(
userInput.Trim(), // let's tolerate leading/trailing whitespaces
allowedFormats,
CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None,
out var result) &&
result <= DateTime.Today &&
result >= DateTime.Today.AddYears(-150)) {
// result is
// 1. Valid date
// 2. At least 150 years ago
// 3. At most today
}
else {
// userInput doesn't meet at least one criterium
}
As #Rafalon suggested, use DateTime.TryParseExact to avoid exceptions and set the format you want.
string dateformat = "12-05";
bool answer = DateTime.TryParseExact(dateformat, "dd-MM-yyyy", CultureInfo.InvariantCulture, System.Globalization.DateTimeStyles.None, out DateTime result);
I have been trying to convert this string to a DateTime object in C#
2019-09-23T08:34:00UTC+1
I've tried using DateTime.Parse but it is throwing an exception for
"String was not recognized as a valid DateTime."
I'm sorry but you seem like a victim of garbage in, garbage out.
That's an unusual format, that's why before I suggest a solution for you, first thing I want to say is "Fix your input first if you can".
Let's say you can't fix your input, then you need to consider a few things;
First of all, if your string has some parts like UTC and/or GMT, there is no custom date and time format specifier to parse them. That's why you need to escape them as a string literal. See this question for more details.
Second, your +1 part looks like a UTC Offset value. The "z" custom format specifier is what you need for parse it but be careful, this format specifier is not recommended for use with DateTime values since it doesn't reflect the value of an instance's Kind property.
As a solution for DateTime, you can parse it like I would suggest;
var s = "2019-09-23T08:34:00UTC+1";
DateTime dt;
if(DateTime.TryParseExact(s, "yyyy-MM-dd'T'HH:mm:ss'UTC'z", CultureInfo.InvariantCulture,
DateTimeStyles.AdjustToUniversal, out dt))
{
Console.WriteLine(dt);
}
which gives you 2019-09-23 07:34:00 as a DateTime and which has Utc as a Kind property.
As a solution for DateTimeOffset - since your string has a UTC Offset value you should consider to parse with this rather than Datetime
-, as Matt commented, you can use it's .DateTime property to get it's data like;
var s = "2019-09-23T08:34:00UTC+1";
DateTimeOffset dto;
if(DateTimeOffset.TryParseExact(s, "yyyy-MM-dd'T'HH:mm:ss'UTC'z", CultureInfo.InvariantCulture,
DateTimeStyles.None, out dto))
{
Console.WriteLine(dto.DateTime);
}
which gives you the same result DateTime but Unspecified as a .Kind property.
But, again, I strongly suggest you to fix your input first.
Use TryParseExact to convert the string to datetime. Here is the sample code to covert the given format(s) to datetime
private static DateTime ParseDate(string providedDate) {
DateTime validDate;
string[] formats = {
"yyyy-MM-ddTHH:mm:ss"
};
var dateFormatIsValid = DateTime.TryParseExact(
providedDate, formats, CultureInfo.InvariantCulture, DateTimeStyles.None, out validDate);
return dateFormatIsValid ? validDate: DateTime.MinValue;
}
Then, use this function to convert the string. I am replacing UTC+1 to empty string
static void Main(string[] args) {
string strdatetime = "2019-09-23T08:34:00UTC+1";
DateTime dateTime = ParseDate(strdatetime.Replace("UTC+1", ""));
Console.WriteLine(dateTime);
}
All,
I'm really new to C# after years of VBA Programming. I have made an attempt at trying to convert a US date which is passed into the script via a parameter into a UK date. (Apologies if this is a really basic question - I am still working through training materials)
The issue I am having is passing the UK date out as a parameter.
Code below:
using System.Globalization;
namespace Dynamic.Script_8D643DCA79B170B
{
// Please use caution when modifying class name, namespace or attributes
[OpenSpan.TypeManagement.DynamicTypeAttribute()]
[OpenSpan.Design.ComponentIdentityAttribute("Script-8D643DCA79B170B")]
public sealed class Program
{
public void Dateformat(Datetime USdate, Datetime UKdate)
{
string value = USdate;
string format = "dd/MM/yyyy";
DateTime result;
if (DateTime.TryParseExact(value, format, CultureInfo.InvariantCulture, DateTimeStyles.None, out result))
{
Console.WriteLine(result.ToString(format));
}
else
{
Console.WriteLine("Date invalid");
}
}
}
}
Essentially I would like to pass a date formatted as MM/dd/YYYY into the script and convert it into UK date format dd/MM/YYYY as a variable. Any help and guidance on how to adapt the above script would be much appreciated.
*****Edit**********
Thanks for all your help and advice so far, I have been able to develop a new script see below:
public string Dateformat(string USdate)
{
string date = USdate; // en-US formatted date
// Convert to DateTime
DateTime parsedDate = DateTime.ParseExact(date, "MM/dd/yyyy", CultureInfo.InvariantCulture);
// Output in en-GB format
return parsedDate.ToString("dd/MM/yyyy");
}
The issue I am having with the above script is that the string was not recognized as a valid DateTime. See screenshot:
The USdate I am passing into the script is formatted in DateTime.
I've tried with several different format strings but I can't get it to parse a date like:
date = "10/16/13";
DateTime endDate = DateTime.ParseExact(date, "M-dd-yy", CultureInfo.InvariantCulture);
What am I missing?!
For it to parse the date your format needs to be the same. Change "M-dd-yy" to "M/dd/yy" Assuming that the month is a single digit and the day is always 2 digits.
Here you go this should work just fine. You just need to be aware that it will set a default time of 12:00 am because you are not specifying the time in your string.
class Program
{
static void Main(string[] args)
{
string date = "10/16/13";
//This is usually the safer way to go
DateTime result;
if(DateTime.TryParse(date, out result))
Console.WriteLine(result);
//I think this is what you were trying to accomplish
DateTime result2 = Convert.ToDateTime(date, CultureInfo.InvariantCulture);
Console.ReadKey();
}
}
I am using below code
DateTime dtt=new DateTime();
dtt = Convert.ToDateTime(FromDate);
// DateTime dtt = DateTime.Parse(FromDate); //this also gives the same error
con = new MySqlConnection(conString);
con.Open();
for (int i = 1; i <= TotalDays; i++)
{
string updateHotelBooking = "Update tbl_hotelbookingdetail set `BookedRoom`=`BookedRoom`+"+1+", `AvailableRoom`=`TotalRoom`-`BookedRoom` where `HotelID`="+HotelID+" AND `CurrentDate`='"+dtt.ToString("dd-MM-yyyy")+"'";
MySqlCommand cmd7=new MySqlCommand(updateHotelBooking,con);
cmd7.ExecuteNonQuery();
dtt = dtt.AddDays(1);
}
This code is in one of my webservice which I am using for iPhone application.
here FromDate is string with value in this formate 15-11-2011 which is coming from the application in string format. I am converting it to DateTime because in loop of total days
I need to add day to dtt.
It is working fine on local host with dtt value 15-11-2011 00:00:00
but when I published it,it gives error
String was not recognize as valid DateTime
This is almost certainly because your server uses a different culture by default - and your code is just using the current thread culture.
You can specify this using DateTime.Parse - or specify the pattern explicitly with DateTime.ParseExact or DateTime.TryParseExact - but we need to know more about where the string is coming from to suggest the best approach. Is it from the user? If so, you should use the user's culture to parse it. Is it a specific format (e.g. from an XML document) instead? If so, parse using that specific format.
Ideally, get rid of the string part entirely - if you're fetching it from a database for example, can you store it and fetch it as a DateTime instead of as a string? It's worth trying to reduce the number of string conversions involved as far as possible.
EDIT: To parse from a fixed format of dd-MM-yyyy I would use:
DateTime value;
if (DateTime.TryParseExact(text, "dd-MM-yyyy",
CultureInfo.InvariantCulture,
DateTimeStyles.AssumeUniversal,
out value))
{
// Value will now be midnight UTC on the given date
}
else
{
// Parsing failed - invalid data
}
What are you culture settings on your local machine and on the server?
The DateTime conversion is dependent on the current culture - dates are written quite differently in different countries.
One way to make the conversion "predictible" is to use the invariant culture:
DateTime dtt = Convert.ToDateTime(FromDate, CultureInfo.InvariantCulture);
the server date format may be in mm/dd/yyyy and you are trying to pass dd/mm/yyyy
using System;
using System.Globalization;
public class Example
{
public static void Main()
{
string[] dateValues = { "30-12-2011", "12-30-2011",
"30-12-11", "12-30-11" };
string pattern = "MM-dd-yy";
DateTime parsedDate;
foreach (var dateValue in dateValues) {
if (DateTime.TryParseExact(dateValue, pattern, null,
DateTimeStyles.None, out parsedDate))
Console.WriteLine("Converted '{0}' to {1:d}.",
dateValue, parsedDate);
else
Console.WriteLine("Unable to convert '{0}' to a date and time.",
dateValue);
}
}
}
// The example displays the following output:
// Unable to convert '30-12-2011' to a date and time.
// Unable to convert '12-30-2011' to a date and time.
// Unable to convert '30-12-11' to a date and time.
// Converted '12-30-11' to 12/30/2011.
Check this for more details
Log (or otherwise provide feedback to yourself) what FromDate is. Maybe it's empty?
May the Language Settings on the Server are different so it does not recognize the dd-MM-yyyy - try using DateTime.ParseExact(dateString, "dd-MM-yyyy", CultureInfo.InvariantCulture);