I have string which contains a time (obtained from a DB):
string user_time = "17:10:03"; //Hours:minutes:seconds
DateTime time_now = DateTime.Now;
How do I compare this string to a DateTime? I'd like something like this:
if(time_now > user_time)
{
//Do something
}
else
{
//Do something
}
DateTime supports comparison, but first you need to parse the date-time string, DateTime.Parse() should suffice:
var dateTimeStr = "17:10:03";
var user_time = DateTime.Parse( dateTimeStr );
var time_now = DateTime.Now;
if( time_now > user_time )
{
// your code...
}
Bear in mind, that comparing dates/times sometimes requires awareness of time-zones to make the comparison meaningful.
The problem is that DateTime.Now includes a date, "17:10:03" doesn't. Do it like this:
Dim dbaseTime As TimeSpan = TimeSpan.Parse("17:10:03")
If DateTime.Now.TimeOfDay > dbaseTime Then
Console.WriteLine("Let's go home")
End If
Do everything in your power to convert that string column type to a datetime column.
You can use DateTime.Compare() along with DateTime.Parse() to convert the string to a DateTime object.
DateTime.Parse Will convert the string into a DateTime object which you can then use to compare.
if (DateTime.Now > DateTime.Parse(user_time))
{
...
}
But you really shouldn't store a time as a string, you should use the native time or datetime format of your database, that way you could use the value of the time in your queries, and index them properly.
if (time_now > Date.Parse(DBString)) {
} else {
}
Related
how i can check a string for a time:
for example I want to input 12:22 and the program must check with dateTime.
The Programm is in C#
Use DateTime.TryParse and if it returns true, the string is a valid date.
Looks like you want to check for a Timespan and not for a datetime, therefore use TimeSpan.TryParse instead.
If you want a specific format, use TimeSpan.TryParseExact.
http://msdn.microsoft.com/en-us/library/3z48198e(v=vs.110).aspx
http://msdn.microsoft.com/en-us/library/dd784009(v=vs.110).aspx
The correct approach here is to not use DateTime but to use TimeSpan as you are dealing with a time rather than a date.
var inputText = "12:22"; // get this from whatever your input is
TimeSpan result;
if (!TimeSpan.TryParse(inputText, out result))
{
// handle error
}
else
{
// everything okay
}
Use DateTime.TryParseExact Method as the following:
if (DateTime.TryParseExact(timeStringValue, timeStringFormat,
new CultureInfo("en-US"),
DateTimeStyles.None,
out dateTimeValue))
{
}
else
{
}
You can try in this way,
TimeSpan t1 = (Convert.ToDateTime(TextBox1.Text)).TimeOfDay;
TimeSpan t2 = DateTime.Now.TimeOfDay;
if(t1 == t2) // Something as you want
Let us know the Output.
I want to display a message only when the datetime is before or on todays date. Here is what I have:
var todaysdate = DateTime.Today;
if (acct.maturityDate <= todaysdate )
{
maturityText.Visible = true;
}
I get a message saying that (acct.maturityDate <= todaysdate ).
Cannot apply operator '<=' to operands of type 'string' and 'system.datetime', candidates are bool <=(system.datetime,system.datetime) (in struct datetime).
Any help is appreciated.
As the error says, maturityData is a string and not a DateTime you need to convert it:
var todaysdate = DateTime.Today;
if (DateTime.Parse(acct.maturityDate) <= todaysdate ) {
maturityText.Visible = true;
}
I'm making a direct parse there, you might want to consider TryParse or ParseExact depending on your needs.
This means that the property acct.maturityDate is of the type string and not the expected type System.DateTime. Convert/parse the property to a DateTime and your problem should be solved, or make sure the property is already a DateTime.
As mentioned in my comment, the type of maturityDate is a string. using DateTime.Parse() would allow you to resolve your issues and so will DateTime.TryParseExact()
Converting to the correct type will allow you to use the correct operators.
Firstly you have to change maturityDate to DateTime type, and then you should use DateTime.Compare method you can refer to this link
If maturityDate must be left as-is, you can either use the DateTime.Parse, DateTime.TryParse, or DateTime.TryParseExact methods.
Parse will throw an exception if maturity date cannot be parsed.
TryParse and TryParseExact will not throw exceptions, but will allow you to make a decision based on whether the date is able to be parsed.
TryParseExact allows you to parse your date even if it doesn't match a standard DateTime format. You simply specify the format string, as well as culture and style information, in the method parameters.
Parse Example:
var todaysdate = DateTime.Today;
if (DateTime.Parse(acct.maturityDate) <= todaysdate ) {
maturityText.Visible = true;
}
TryParse Example:
var todaysdate = DateTime.Today;
DateTime dt;
if (DateTime.TryParse(acct.maturityDate, out dt)
{
if (dt <= todaysdate)
{
maturityText.Visible = true;
}
}
TryParseExact Example:
var todaysdate = DateTime.Today;
DateTime dt;
// use whatever format string matches appropriately
if (DateTime.TryParseExact(acct.maturityDate, "YYYY-MM-dd HH:mm:ss"
, CultureInfo.InvariantCulture
, DateTimeStyles.None, out dt)
{
if (dt <= todaysdate)
{
maturityText.Visible = true;
}
}
I have a function that checks for null values then converts dates if they are not null
the below function just had "08/09/13" sent to it (English format) and i got "String was not recognized as a valid DateTime."
anyone help me as to why? do i need to tell the something somewhere is uses English format?
Thanks
public static DateTime DateTimeCheck(object objDateTime)
{
if (objDateTime == null || objDateTime == "")
return default(DateTime);
return Convert.ToDateTime(objDateTime);
}
I don't understand why you passed an object as a parameter instead of string first of all.
Try this instead;
public static DateTime DateTimeCheck(object objDateTime)
{
...
return DateTime.ParseExact(objDateTime.ToString(),"dd/MM/yy",CultureInfo.InvariantCulture);
}
Of course, this throws exception if your object is not formatted same as with "dd/MM/yy".
Take a look at;
Custom Date and Time Format Strings
You can use the overloaded method that accepts the culture information:
Convert.ToDateTime(o, new CultureInfo("en-Gb"));
To get or set the current culture you can use:
System.Threading.Thread.CurrentThread.CurrentCulture
You might be in a different culture with a different default date format. However you can use ParseExact to parse in the expected format. For example:
CultureInfo provider = CultureInfo.InvariantCulture;
DateTime result = DateTime.ParseExact("25/12/82","dd/MM/yy",provider);
I know this not what you are looking for but that's how to be sure that some object has date time value in it something like that :
public static DateTime DateTimeCheck(object objDateTime)
{
DateTime dateTime ;
if (objDateTime != null)
{
if (DateTime.TryParse(objDateTime.ToString(), out dateTime))
{
return Convert.ToDateTime(objDateTime);
}
}
return default(DateTime);
}
Try this:
DateTime.ParseExact((string)objDateTime,"dd/MM/yyyy",CultureInfo.InvariantCulture);
I want to add a date in session (date1) like this:
Session["DateLesson"] = date1.ToString("dd.MM.yyyy");
Now from the session I want take this value:
var asd = Session["DateLesson"];
/*asd = "20.04.2012"*/
var datelesson = DateTime.Parse((string) asd);
And it gives me this exception:
FormatException not recognized as a valid DateTime
A period is not a valid/standard separator character in most locales. You'll need to use DateTime.ParseExact() in combination with a format string to tell the function how to read it. More importantly, if reading it back to a datetime is your main goal, why not just put the datetime in the session as is? That seems way more efficient, easier, and more maintainable to me.
Why persist your date as a string?
You could simply store it like this:
Session["DateLesson"] = date1;
And then retrieve it like this:
var datelesson = (DateTime)Session["DateLesson"];
string value = "20.04.2012";
DateTime datetime = DateTime.ParseExact(value, "dd.MM.yyyy", null);
This will return 4/20/2012 12:00:00:00 AM
Don't keep value as a string but as an object of the initial type:
public DateTime? DateLesson
{
get
{
DateTime? dateTime = Session["DateLesson"] as DateTime?;
if (dateTime.HasValue) // not null
{
// use dateTime.Value
}
}
set
{
Session["DateLesson"] = value;
}
}
I want today's date in mm/dd/yyyy format from a DateTime variable. How to get it?
I need to check this with some date variable so it must be also in date variable format?plz help
Ex: i need to get today date in mm/dd/yyyy format and i already date which is datetime datatype in mm/dd/yyyy format and i have to compare them
You should use DateTime.Today:
DateTime today = DateTime.Today; // As DateTime
string s_today = today.ToString("MM/dd/yyyy"); // As String
Edit: You edited your post to add another question, so here comes my edit to supply at least some sort of answer.
Update While you can use DateTime.Compare() you should use plain comparisson:
if(today < otherdate)
{
// Do something.
}
Alternatively, you can use DateTime-variables to check against other DateTime-variables using the DateTime.Compare() method. Both otpions will work and it comes down to preference and what you want to do with the result.
int result = DateTime.Compare(today, otherdate);
if(result < 0)
MessageBox.Show("Today is earlier than the 'otherdate'");
elseif(result > 0)
MessageBox.Show("Today is later than the 'other date'");
else
MessageBox.Show("Dates are equal...");
string datestring = DateTime.Now.ToString("MM/dd/yyyy");
MSDN say: Custom Date and Time Format Strings
To convert DateTime variable to string in the specified format:
DateTime d = ...;
string s = d.ToString("MM/dd/yyyy");
If you want to compare only date part of DateTime, not time part:
DateTime d1 = DateTime.Parse("10/10/2011");
DateTime d2 = DateTime.Parse("01/01/2011");
if (d1.Date > d2.Date)
{
// do the stuff
}
DateTime.Now.ToString("MM/dd/yyyy");
DateTime.Today.ToString("MM/dd/yyyy");
DateTime.Parse is what you are looking for...