DateTime.CompareTo Method (DateTime)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
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.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- value
- Type: System.DateTime
The object to compare to this instance.
Return Value
Type: System.Int32A signed integer that indicates the relationship between this instance and the value parameter, as shown in the following table.
Value | Description |
|---|---|
Less than zero | This instance is earlier than value. |
Zero | This instance is the same as value. |
Greater than zero | This instance is later than value. |
Implements
IComparable(Of T).CompareTo(T)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.
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.
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 Example Private Enum DateComparisonResult Earlier = -1 Later = 1 TheSame = 0 End Enum Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock) 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) outputBlock.Text += String.Format("CompareTo method returns {0}: {1:d} is {2} than {3:d}", _ CInt(comparison), thisDate, comparison.ToString().ToLower(), _ thisDateLastYear) + vbCrLf ' Compare today to next year comparison = CType(thisDate.CompareTo(thisDateNextYear), DateComparisonResult) outputBlock.Text += String.Format("CompareTo method returns {0}: {1:d} is {2} than {3:d}", _ CInt(comparison), thisDate, comparison.ToString().ToLower(), _ thisDateNextYear) + vbCrLf 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