How to compare time from datetime in hh:mm:ss format in C# ?

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hi all,
i have visual studio winform c#
i want to compare the time from DateTime in hh:mm format in a specific range.
but it is not working

in my source code below the range is [start_time ,End_time].

In other words, from the datetime i want to extract the time only
e.g: 2015-04-05 2:14:00 extract only 2:14:00
and compare it with a specific range that has also the same format.

What I have tried:

C#

DateTime current_time = DateTime.Now;
var End_time=current_time.ToString("hh:mm"); //End_time
var start_time = current_time.AddHours(-2).ToString("hh:mm");//start_time 

DataTable dchild= new DataTable();
string query=SELECT DATE_FORMAT( date_created,  '%h:%i:%s' ) time_created from table ;
adap_child = new MySqlDataAdapter(query, strconnection);
            adap_child.Fill(dchild);   
  
foreach (DataRow items in dchild.Rows)
{
  var  date_to_be_compared = (int)items["time_created"];
if(time_to_compared >=start_time && date_to_be_compared<=End_time)//error appears here
   {
     //code
    }
else
{
//code
}

}

Posted 7-Apr-16 2:23am

Armel_Djient

Updated 7-Apr-16 6:44am

phil.o

v2

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Comments

Richard MacCutchan 7-Apr-16 9:03am

Why are you converting the DateTime values to strings? Just compare them using the numeric values.

Armel_Djient 7-Apr-16 9:55am

because i want to fetch only the time from DateTime. Is there another way to fetch only time without converting the DateTime values to string?

PIEBALDconsult 7-Apr-16 9:57am

Yes, as Solution 1 states.

PIEBALDconsult 7-Apr-16 9:56am

Please don't do that.

2 solutions

Solution 2

Change what you get back from the SELECT to be the DATETIME value that is actually stored in the DB. Then get the TimeOfDay part and use that everywhere else!

Try something like:

C#

DateTime current_time = DateTime.Now;
TimeSpan End_time=current_time.TimeOfDay; //End_time
TimeSpan start_time = End_time.SubtractHours(-2);//start_time 

DataTable dchild= new DataTable();
string query = "SELECT date_created FROM table";
adap_child = new MySqlDataAdapter(query, strconnection);
adap_child.Fill(dchild);   
  
foreach (DataRow items in dchild.Rows)
{
  TimeSpan time_to_be_compared = ((DateTime)items["date_created"]).TimeOfDay;
  if (start_time <= time_to_be_compared && time_to_be_compared <= End_time)
  {
     //code
  }
  else
  {
     //code
  }
}

Posted 7-Apr-16 6:43am

Matt T Heffron

Updated 7-Apr-16 6:46am

v2

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F-ES Sitecore · Accepted Answer · 2016-04-07T03:37:00

Solution 1

You can get the time as a TimeSpan object

C#

DateTime current_time = DateTime.Now;
DateTime date_to_be_compared = DateTime.ParseExact("12 Aug 2014 13:45:22", "dd MMM yyyy HH:mm:ss", System.Globalization.CultureInfo.CurrentCulture);

TimeSpan ts_current = current_time.TimeOfDay;
TimeSpan ts_compare = date_to_be_compared.TimeOfDay;

if (ts_current > ts_compare)
{
    System.Diagnostics.Debug.WriteLine("Current time is after compare time");
}
else
{
    System.Diagnostics.Debug.WriteLine("Current time is not after compare time");
}

Posted 7-Apr-16 3:37am

F-ES Sitecore

Comments

Armel_Djient 7-Apr-16 10:07am

thanks for your reply. the problem in your source code is :
DateTime date_to_be_compared = DateTime.ParseExact("12 Aug 2014 13:45:22", "dd MMM yyyy HH:mm:ss", System.Globalization.CultureInfo.CurrentCulture);

the date_to_be_compared that you parse is static "12 Aug 2014 13:45:22" .
But mine is not.
in my source code, the date_to_be_compared is fetched from the datatable in this format "hh:mm"

PIEBALDconsult 7-Apr-16 10:11am

Dates should _never_ be stored as strings in databases. Please check the datatype.

F-ES Sitecore 7-Apr-16 10:44am

That's just sample code, make date_to_be_compared the datetime you actually have.

Armel_Djient 7-Apr-16 10:37am

in the database the date is stored in format of DATETIME.(eg: 2015-11-16 10:45:48)
now through a sql command i fetched only the time from this datetime, ie 10:45:48
which represents the date_to_be compared or the time_to_be_compared

As you can imagine i have more than one row in my database. that's why i fetched them and put in the datatable.

In your source code u know in advance what is date_to_be_compared that's why you wrote
DateTime date_to_be_compared = DateTime.ParseExact("12 Aug 2014 13:45:22", "dd MMM yyyy HH:mm:ss", System.Globalization.CultureInfo.CurrentCulture);

if i modified your code and write something like that, i will get error
foreach (DataRow items in dchild.Rows)
{
DateTime date_to_be_compared = DateTime.ParseExact(items["time_created"], "dd MMM yyyy HH:mm:ss", System.Globalization.CultureInfo.CurrentCulture);
}

where items["time_created"] represents for example the first row's value 10:45:48