DateTime.CompareTo Method (DateTime)


Compares the value of this instance to a specified DateTime value and returns an integer that indicates whether this instance is earlier than, the same as, or later than the specified DateTime value.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

Public Function CompareTo (
	value As Date
) As Integer


Type: System.DateTime

The object to compare to the current instance.

Return Value

Type: System.Int32

A signed number indicating the relative values of this instance and the value parameter.



Less than zero

This instance is earlier than value.


This instance is the same as value.

Greater than zero

This instance is later than value.

To determine the relationship of the current instance to value, the CompareTo method compares the Ticks property of the current instance and value but ignores their Kind property. Before comparing DateTime objects, make sure that the objects represent times in the same time zone. You can do this by comparing the values of their Kind properties.

This method implements the System.IComparable(Of T) interface and performs slightly better than the DateTime.CompareTo(Object) method overload because it does not have to convert the value parameter to an object.

The following example instantiates three DateTime objects, one that represents today's date, another that represents the date one year previously, and a third that represents the date one year in the future. It then calls the CompareTo(DateTime) method and displays the result of the comparison.

Option Strict On

Module DateTimeComparison
   Private Enum DateComparisonResult
      Earlier = -1
      Later = 1
      TheSame = 0
   End Enum

   Public Sub Main()

      Dim thisDate As Date = Date.Today

      ' Define two DateTime objects for today's date 
      ' next year and last year		
      Dim thisDateNextYear, thisDateLastYear As Date

      ' Call AddYears instance method to add/substract 1 year
      thisDateNextYear = thisDate.AddYears(1)
      thisDateLastYear = thisDate.AddYears(-1)   

      ' Compare dates
      Dim comparison As DateComparisonResult
      ' Compare today to last year
      comparison = CType(thisDate.CompareTo(thisDateLastYear), DateComparisonResult)
      Console.WriteLine("CompareTo method returns {0}: {1:d} is {2} than {3:d}", _ 
                        CInt(comparison), thisDate, comparison.ToString().ToLower(), _ 

      ' Compare today to next year
      comparison = CType(thisDate.CompareTo(thisDateNextYear), DateComparisonResult)
      Console.WriteLine("CompareTo method returns {0}: {1:d} is {2} than {3:d}", _
                        CInt(comparison), thisDate, comparison.ToString().ToLower(), _
   End Sub
End Module
' If run on October 20, 2006, the example produces the following output:
'    CompareTo method returns 1: 10/20/2006 is later than 10/20/2005
'    CompareTo method returns -1: 10/20/2006 is earlier than 10/20/2007

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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