Develop Reference

How to remove time in second after retrieve from database?

i have this label retrieve time from database and display in label. but time in database also consist of second for example 03:45:29, how can i remove the time in second to become 03:45 in the label after retrieve it. this is my code:LabelDateMarker.Text = LabelDateMarker.Text + " " + dr[3].ToString();

Assuming dr is a SqlDataReader or similar, you probably want to cast to DateTime, then format the value appropriately:
DateTime dateTime = (DateTime) dr[3];
string formatted = dateTime.ToString("yyyy-MM-dd HH:mm", CultureInfo.InvariantCulture);
LabelDateMarker.Text += " " + formatted;
Here yyyy-MM-dd HH:mm is a custom date/time format string indicating that you want the hours and minutes after the ISO-8601-formatted date part.
I've used the invariant culture when formatting to avoid this giving unexpected results in locales that don't use the Gregorian calendar by default.
(I've assumed the value is always non-null. If it might be null, you should check it with dr.IsDBNull(3) first.)

Use a format string for this
((DateTime)dr[3]).ToString("yyyy-MM-dd HH:mm", CultureInfo.InvariantCulture);
instead of
dr[3].ToString();
For more information have a look at the available formats at the MSDN

Unable to create date with current time from string

I am taking selected date from telerik date picker and want to take that selected date and current system time by 24 hours format and want date like this:
For Ex: Current Date = dd/mm/yy HH:Minutes:Seconds
21/1/2016 14:48:21
This is my code:
DateTime dt = DateTime.ParseExact(Datepicker1.SelectedDate.Value.ToShortDateString(), "dd/MM/yyyy", CultureInfo.InvariantCulture);//Error:String was not recognized as a valid DateTime.
Datepicker1.SelectedDate.Value= {1/21/2016 12:00:00 AM}
Datepicker1.SelectedDate.Value.ToShortDateString()=1/21/2016
Error:String was not recognized as a valid DateTime on Datetime.ParseExact.

Change your format in the ParseExact from
"dd/MM/yyyy"
to
"M/d/yyyy" or "M/d/yyyy h:m:s tt" //the first one use .ToShortDateString(), the second one for 1/21/2016 12:00:00 AM
The first one only takes care for case like 21/12/1997
The second one takes care 12/21/1997, 2/21/1997, 12/2/1997, and 2/1/1997 in addition to take care of time info
Also, note that you may consider to have multiple formats (just in case): "d/M/yyyy H:m:s", "d/M/yyyy h:m:s tt" to take care of the case where day and month are swapped and when you have AM/PM.
MSDN link.

#yourDateTime.FormattedReviewDate.ToString("MMM dd,yyyy")
You might even just add a simple property to dateTime for the formatted display:
public string FormattedReviewDate
{
get { return ReviewDate.ToString("MMM dd,yyyy"); }
}
Note: Give your needed format

You don't need to parse anything.
Your Datepicker1.SelectedDate.Value is already DateTime, just assign this value to your dt variable.
DateTime dt = Datepicker1.SelectedDate.Value;
If you want to get it's string representation based on your format, just use ToString method with proper format.
string formattedDate = dt.ToString("dd/M/yyyy HH:mm:ss", CultureInfo.InvariantCulture);
which returns 21/1/2016 14:48:21 as a string.
Also if you want 1/21/2016 as a string, just change your format to M/dd/yyyy like;
string formattedDate = dt.ToString("M/dd/yyyy", CultureInfo.InvariantCulture);

Split Date and Time in DataGridView

I have a DATETIME column in DataGridView, which contains both the date and the time. I need to separate the date from the time. The date should be displayed in one column and the time in another column.
I've tried something but it just gives either the date only or the time only; however, I needed them both separately.

You may format the cells of a column:
dataGridView.Columns[#].DefaultCellStyle.Format = "MM/dd/yyyy";
dataGridView.Columns[#].DefaultCellStyle.Format = "HH:mm";
Replace # with target columns.
All of the regular DateTime formatting options are available for the above example. You may tailor it to your needs. To review the available options, refer to MSDN's Custom Date and Time Formatting Strings documentation page.

You can simply do (example):
DateTime dt = DateTime.Now;
string date = dt.ToShortDateString();
string time = dt.ToShortTimeString();
Then, insert into corresponding DataGridView's cell:
dataGridView1[0, 1].Value = date;
dataGridView1[0, 2].Value = time;

how can i assign only year say 2011 in a datetime variable in c#

I have a asp Text box as
where the user will fill only a year value, For this value I have Datetime type Property in c# application and Date type column in DB. So I want to convert that txtYear.Text to DateTime But it will only hold and/or show the year. Please help me in this situation.

A DateTime object will always hold a complete DateTime value, you can't use it to store a year only. (what use would that be anyway?) Besides, the datatype of a "year" is int, not DateTime.
So, I'd like to suggest changing your property to datatype int, both in your code and database.

To display just the year use the format "yyyy".
string s = "2011";
DateTime d = new DateTime(int.Parse(s), 1, 1);
Console.WriteLine(d.ToString("yyyy"));
Console.WriteLine(d);

You have to specify the format of the DateTime value you are manipulating:
String dateTimeFormat = "yyyy";
To show only a part of the DateTime value use the following:
dateTimeValue.ToString(dateTimeFormat);
To read a String value that represents a year into a DateTime use the following:
DateTime.ParseExact(stringValue, dateTimeFormat, CultureInfo.InvariantCulture);
DateTime.ParseExact Method (String, String, IFormatProvider) converts the specified string representation of a date and time to its DateTime equivalent using the specified format and culture-specific format information. The format of the string representation must match the specified format exactly.
DateTime.ToString Method converts the value of the current DateTime object to its equivalent string representation.

Rather than applying any string manipulating function make use of Year property. Check the documentation on the msdn by visiting below link.
DateTime.Year Property

A DateTime always has a full date component. When you create the DateTime instance, you'll need to assign a month and day, but you can ignore them in your usage.
DateTime d = new DateTime(int.Parse(txtYear.Text, 1, 1);
txtYear.Text = d.ToString("yyyy");
Even better would be not to use a DateTime but just use int. If you have only a year, you only need an int.

i assume the text box name is txYear
DateTime dt = new DateTime (Convert.ToInt32(txYear.text),1,1)
save this dt value in database

If you want only the year, why don't you make it of type smallint?
Anyway if you do really want to make it an year,
DateTime x = new DateTime(Convert.ToInt32(txtYear.text), 1, 1);
But make sure you validate that txtYear.text actually does have a valid year.

That is how I did and it worked.
string format = "yyyy";
var CurrentYear = DateTime.Now.ToString(format);

OWC11 Date Formatting Ignored

I am creating an Excel document using owc11. I am providing the dates in dd/mm/yyyy format. I am doing something like this in the code:
for (..looping through results..)
{
Range c = EmailStats.putCellValue(sheet, row, 1, val);
c.set_NumberFormat("dd/mm/yyyy");
}
private static Range putCellValue(Worksheet sheet, int row, int col, String val)
{
Range cell = (Range) sheet.Cells[row, col];
cell.set_Value(XlRangeValueType.xlRangeValueDefault, val);
return cell;
}
Now when for the val argument I set the date format as "dd/mm/yyyy" or not set it at all, the behaviour I get is mm/dd/yyyy from the 1st of a month up and till the 12th and then it swaps back to dd/mm/yyyy. So owc11 thinks that it knows better and swaps the days and month around (like in the US format) and when it is over the 12th date it sticks to the UK format.
Val is declared as String because it may not always be a date. It may be a date, a day, a user name, group name etc depending on how we group/sort our data. Also it may be a selection of days.
After experimenting a while I figured out that the only way to solve this is to use the universal date format of yyyy/mm/dd. However that may create other integration problems. So I was hoping that there may be a way to enforce the dd/mm/yyyy format, so please any suggestions are welcome.

Try to set val as not string. Try assign val as DateTime.
cell.set_Value(XlRangeValueType.xlRangeValueDefault, val);