How to: Extract the Day of the Week from a Specific Date
.NET makes it easy to determine the ordinal day of the week for a particular date, and to display the localized weekday name for a particular date. An enumerated value that indicates the day of the week corresponding to a particular date is available from the DayOfWeek or DayOfWeek property. In contrast, retrieving the weekday name is a formatting operation that can be performed by calling a formatting method, such as a date and time value's ToString
method or the String.Format method. This article shows how to perform these formatting operations.
Extract a number indicating the day of the week
Use the static DateTime.Parse or DateTimeOffset.Parse method to convert the string representation of a date to a DateTime or a DateTimeOffset value.
Use the DateTime.DayOfWeek or DateTimeOffset.DayOfWeek property to retrieve a DayOfWeek value that indicates the day of the week.
If necessary, cast (in C#) or convert (in Visual Basic) the DayOfWeek value to an integer.
The following example displays an integer that represents the day of the week of a specific date:
using System;
public class Example
{
public static void Main()
{
DateTime dateValue = new DateTime(2008, 6, 11);
Console.WriteLine((int) dateValue.DayOfWeek);
}
}
// The example displays the following output:
// 3
Module Example
Public Sub Main()
Dim dateValue As Date = #6/11/2008#
Console.WriteLine(dateValue.DayOfWeek)
End Sub
End Module
' The example displays the following output:
' 3
Extract the abbreviated weekday name
Use the static DateTime.Parse or DateTimeOffset.Parse method to convert the string representation of a date to a DateTime or a DateTimeOffset value.
You can extract the abbreviated weekday name of the current culture or of a specific culture:
To extract the abbreviated weekday name for the current culture, call the date and time value's DateTime.ToString(String) or DateTimeOffset.ToString(String) instance method, and pass the string
ddd
as theformat
parameter. The following example illustrates the call to the ToString(String) method:using System; public class Example { public static void Main() { DateTime dateValue = new DateTime(2008, 6, 11); Console.WriteLine(dateValue.ToString("ddd")); } } // The example displays the following output: // Wed
Module Example Public Sub Main() Dim dateValue As Date = #6/11/2008# Console.WriteLine(dateValue.ToString("ddd")) End Sub End Module ' The example displays the following output: ' Wed
To extract the abbreviated weekday name for a specific culture, call the date and time value's DateTime.ToString(String, IFormatProvider) or DateTimeOffset.ToString(String, IFormatProvider) instance method. Pass the string
ddd
as theformat
parameter. Pass either a CultureInfo or a DateTimeFormatInfo object that represents the culture whose weekday name you want to retrieve as theprovider
parameter. The following code illustrates a call to the ToString(String, IFormatProvider) method using a CultureInfo object that represents the fr-FR culture:using System; using System.Globalization; public class Example { public static void Main() { DateTime dateValue = new DateTime(2008, 6, 11); Console.WriteLine(dateValue.ToString("ddd", new CultureInfo("fr-FR"))); } } // The example displays the following output: // mer.
Imports System.Globalization Module Example Public Sub Main() Dim dateValue As Date = #6/11/2008# Console.WriteLine(dateValue.ToString("ddd", New CultureInfo("fr-FR"))) End Sub End Module ' The example displays the following output: ' mer.
Extract the full weekday name
Use the static DateTime.Parse or DateTimeOffset.Parse method to convert the string representation of a date to a DateTime or a DateTimeOffset value.
You can extract the full weekday name of the current culture or of a specific culture:
To extract the weekday name for the current culture, call the date and time value's DateTime.ToString(String) or DateTimeOffset.ToString(String) instance method, and pass the string
dddd
as theformat
parameter. The following example illustrates the call to the ToString(String) method:using System; public class Example { public static void Main() { DateTime dateValue = new DateTime(2008, 6, 11); Console.WriteLine(dateValue.ToString("dddd")); } } // The example displays the following output: // Wednesday
Module Example Public Sub Main() Dim dateValue As Date = #6/11/2008# Console.WriteLine(dateValue.ToString("dddd")) End Sub End Module ' The example displays the following output: ' Wednesday
To extract the weekday name for a specific culture, call the date and time value's DateTime.ToString(String, IFormatProvider) or DateTimeOffset.ToString(String, IFormatProvider) instance method. Pass the string
dddd
as theformat
parameter. Pass either a CultureInfo or a DateTimeFormatInfo object that represents the culture whose weekday name you want to retrieve as theprovider
parameter. The following code illustrates a call to the ToString(String, IFormatProvider) method using a CultureInfo object that represents the es-ES culture:using System; using System.Globalization; public class Example { public static void Main() { DateTime dateValue = new DateTime(2008, 6, 11); Console.WriteLine(dateValue.ToString("dddd", new CultureInfo("es-ES"))); } } // The example displays the following output: // miƩrcoles.
Imports System.Globalization Module Example Public Sub Main() Dim dateValue As Date = #6/11/2008# Console.WriteLine(dateValue.ToString("dddd", _ New CultureInfo("es-ES"))) End Sub End Module ' The example displays the following output: ' miƩrcoles.
Example
The following example illustrates calls to the DateTime.DayOfWeek and DateTimeOffset.DayOfWeek properties to retrieve the number that represents the day of the week for a particular date. It also includes calls to the DateTime.ToString and DateTimeOffset.ToString methods to extract the abbreviated weekday name and the full weekday name.
using System;
using System.Globalization;
public class Example
{
public static void Main()
{
string dateString = "6/11/2007";
DateTime dateValue;
DateTimeOffset dateOffsetValue;
try
{
DateTimeFormatInfo dateTimeFormats;
// Convert date representation to a date value
dateValue = DateTime.Parse(dateString, CultureInfo.InvariantCulture);
dateOffsetValue = new DateTimeOffset(dateValue,
TimeZoneInfo.Local.GetUtcOffset(dateValue));
// Convert date representation to a number indicating the day of week
Console.WriteLine((int) dateValue.DayOfWeek);
Console.WriteLine((int) dateOffsetValue.DayOfWeek);
// Display abbreviated weekday name using current culture
Console.WriteLine(dateValue.ToString("ddd"));
Console.WriteLine(dateOffsetValue.ToString("ddd"));
// Display full weekday name using current culture
Console.WriteLine(dateValue.ToString("dddd"));
Console.WriteLine(dateOffsetValue.ToString("dddd"));
// Display abbreviated weekday name for de-DE culture
Console.WriteLine(dateValue.ToString("ddd", new CultureInfo("de-DE")));
Console.WriteLine(dateOffsetValue.ToString("ddd",
new CultureInfo("de-DE")));
// Display abbreviated weekday name with de-DE DateTimeFormatInfo object
dateTimeFormats = new CultureInfo("de-DE").DateTimeFormat;
Console.WriteLine(dateValue.ToString("ddd", dateTimeFormats));
Console.WriteLine(dateOffsetValue.ToString("ddd", dateTimeFormats));
// Display full weekday name for fr-FR culture
Console.WriteLine(dateValue.ToString("ddd", new CultureInfo("fr-FR")));
Console.WriteLine(dateOffsetValue.ToString("ddd",
new CultureInfo("fr-FR")));
// Display abbreviated weekday name with fr-FR DateTimeFormatInfo object
dateTimeFormats = new CultureInfo("fr-FR").DateTimeFormat;
Console.WriteLine(dateValue.ToString("dddd", dateTimeFormats));
Console.WriteLine(dateOffsetValue.ToString("dddd", dateTimeFormats));
}
catch (FormatException)
{
Console.WriteLine("Unable to convert {0} to a date.", dateString);
}
}
}
// The example displays the following output:
// 1
// 1
// Mon
// Mon
// Monday
// Monday
// Mo
// Mo
// Mo
// Mo
// lun.
// lun.
// lundi
// lundi
Imports System.Globalization
Module Example
Public Sub Main()
Dim dateString As String = "6/11/2007"
Dim dateValue As Date
Dim dateOffsetValue As DateTimeOffset
Try
Dim dateTimeFormats As DateTimeFormatInfo
' Convert date representation to a date value
dateValue = Date.Parse(dateString, CultureInfo.InvariantCulture)
dateOffsetValue = New DateTimeOffset(dateValue, _
TimeZoneInfo.Local.GetUtcOffset(dateValue))
' Convert date representation to a number indicating the day of week
Console.WriteLine(dateValue.DayOfWeek)
Console.WriteLine(dateOffsetValue.DayOfWeek)
' Display abbreviated weekday name using current culture
Console.WriteLine(dateValue.ToString("ddd"))
Console.WriteLine(dateOffsetValue.ToString("ddd"))
' Display full weekday name using current culture
Console.WriteLine(dateValue.ToString("dddd"))
Console.WriteLine(dateOffsetValue.ToString("dddd"))
' Display abbreviated weekday name for de-DE culture
Console.WriteLine(dateValue.ToString("ddd", New CultureInfo("de-DE")))
Console.WriteLine(dateOffsetValue.ToString("ddd", _
New CultureInfo("de-DE")))
' Display abbreviated weekday name with de-DE DateTimeFormatInfo object
dateTimeFormats = New CultureInfo("de-DE").DateTimeFormat
Console.WriteLine(dateValue.ToString("ddd", dateTimeFormats))
Console.WriteLine(dateOffsetValue.ToString("ddd", dateTimeFormats))
' Display full weekday name for fr-FR culture
Console.WriteLine(dateValue.ToString("ddd", New CultureInfo("fr-FR")))
Console.WriteLine(dateOffsetValue.ToString("ddd", _
New CultureInfo("fr-FR")))
' Display abbreviated weekday name with fr-FR DateTimeFormatInfo object
dateTimeFormats = New CultureInfo("fr-FR").DateTimeFormat
Console.WriteLine(dateValue.ToString("dddd", dateTimeFormats))
Console.WriteLine(dateOffsetValue.ToString("dddd", dateTimeFormats))
Catch e As FormatException
Console.WriteLine("Unable to convert {0} to a date.", dateString)
End Try
End Sub
End Module
' The example displays the following output to the console:
' 1
' 1
' Mon
' Mon
' Monday
' Monday
' Mo
' Mo
' Mo
' Mo
' lun.
' lun.
' lundi
' lundi
Individual languages might provide functionality that duplicates or supplements the functionality provided by .NET. For example, Visual Basic includes two such functions:
Weekday
, which returns a number that indicates the day of the week of a particular date. It considers the ordinal value of the first day of the week to be one, whereas the DateTime.DayOfWeek property considers it to be zero.WeekdayName
, which returns the name of the week in the current culture that corresponds to a particular weekday number.
The following example illustrates the use of the Visual Basic Weekday
and WeekdayName
functions:
Imports System.Globalization
Imports System.Threading
Module Example
Public Sub Main()
Dim dateValue As Date = #6/11/2008#
' Get weekday number using Visual Basic Weekday function
Console.WriteLine(Weekday(dateValue)) ' Displays 4
' Compare with .NET DateTime.DayOfWeek property
Console.WriteLine(dateValue.DayOfWeek) ' Displays 3
' Get weekday name using Weekday and WeekdayName functions
Console.WriteLine(WeekdayName(Weekday(dateValue))) ' Displays Wednesday
' Change culture to de-DE
Dim originalCulture As CultureInfo = Thread.CurrentThread.CurrentCulture
Thread.CurrentThread.CurrentCulture = New CultureInfo("de-DE")
' Get weekday name using Weekday and WeekdayName functions
Console.WriteLine(WeekdayName(Weekday(dateValue))) ' Displays Donnerstag
' Restore original culture
Thread.CurrentThread.CurrentCulture = originalCulture
End Sub
End Module
You can also use the value returned by the DateTime.DayOfWeek property to retrieve the weekday name of a particular date. This process requires only a call to the ToString method on the DayOfWeek value returned by the property. However, this technique doesn't produce a localized weekday name for the current culture, as the following example illustrates:
using System;
using System.Globalization;
using System.Threading;
public class Example
{
public static void Main()
{
// Change current culture to fr-FR
CultureInfo originalCulture = Thread.CurrentThread.CurrentCulture;
Thread.CurrentThread.CurrentCulture = new CultureInfo("fr-FR");
DateTime dateValue = new DateTime(2008, 6, 11);
// Display the DayOfWeek string representation
Console.WriteLine(dateValue.DayOfWeek.ToString());
// Restore original current culture
Thread.CurrentThread.CurrentCulture = originalCulture;
}
}
// The example displays the following output:
// Wednesday
Imports System.Globalization
Imports System.Threading
Module Example
Public Sub Main()
' Change current culture to fr-FR
Dim originalCulture As CultureInfo = Thread.CurrentThread.CurrentCulture
Thread.CurrentThread.CurrentCulture = New CultureInfo("fr-FR")
Dim dateValue As Date = #6/11/2008#
' Display the DayOfWeek string representation
Console.WriteLine(dateValue.DayOfWeek.ToString())
' Restore original current culture
Thread.CurrentThread.CurrentCulture = originalCulture
End Sub
End Module
' The example displays the following output:
' Wednesday