DateTime.CompareTo Método

Source:

DateTime.cs

Source:

DateTime.cs

Source:

DateTime.cs

public:
 virtual int CompareTo(DateTime value);

public int CompareTo (DateTime value);

abstract member CompareTo : DateTime -> int
override this.CompareTo : DateTime -> int

Public Function CompareTo (value As DateTime) As Integer

Parámetros

Devoluciones

Número con signo que indica los valores relativos de esta instancia y del parámetro value.

Implementaciones

Ejemplos

En el ejemplo siguiente se crean instancias de tres DateTime objetos, uno que representa la fecha de hoy, otra que representa la fecha de un año anteriormente y una tercera que representa la fecha de un año en el futuro. A continuación, llama al CompareTo(DateTime) método y muestra el resultado de la comparación.

open System

type DateComparisonResult =
    | Earlier = -1
    | Later = 1
    | TheSame = 0

[<EntryPoint>]
let main _ =
    let thisDate = DateTime.Today

    // Define two DateTime objects for today's date next year and last year		
    // Call AddYears instance method to add/substract 1 year
    let thisDateNextYear = thisDate.AddYears 1
    let thisDateLastYear = thisDate.AddYears -1

    // Compare today to last year
    let comparison = thisDate.CompareTo thisDateLastYear |> enum<DateComparisonResult>
    printfn $"CompareTo method returns {int comparison}: {thisDate:d} is {comparison.ToString().ToLower()} than {thisDateLastYear:d}"

    // Compare today to next year
    let comparison = thisDate.CompareTo thisDateNextYear |> enum<DateComparisonResult>
    printfn $"CompareTo method returns {int comparison}: {thisDate:d} is {comparison.ToString().ToLower()} than {thisDateNextYear:d}"
                        
    0

// If run on December 31, 2021, the example produces the following output:
//    CompareTo method returns 1: 12/31/2021 is later than 12/31/2020
//    CompareTo method returns -1: 12/31/2021 is earlier than 12/31/2022

using System;

public class DateTimeComparison
{
   private enum DateComparisonResult
   {
      Earlier = -1,
      Later = 1,
      TheSame = 0
   };

   public static void Main()
   {
      DateTime thisDate = DateTime.Today;

      // Define two DateTime objects for today's date
      // next year and last year		
      DateTime thisDateNextYear, thisDateLastYear;

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

      // Compare dates
      //
      DateComparisonResult comparison;
      // Compare today to last year
      comparison = (DateComparisonResult) thisDate.CompareTo(thisDateLastYear);
      Console.WriteLine("CompareTo method returns {0}: {1:d} is {2} than {3:d}",
                        (int) comparison, thisDate, comparison.ToString().ToLower(),
                        thisDateLastYear);

      // Compare today to next year
      comparison = (DateComparisonResult) thisDate.CompareTo(thisDateNextYear);
      Console.WriteLine("CompareTo method returns {0}: {1:d} is {2} than {3:d}",
                        (int) comparison, thisDate, comparison.ToString().ToLower(),
                        thisDateNextYear);
   }
}
//
// 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

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(), _ 
                        thisDateLastYear)
      
      ' 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(), _
                        thisDateNextYear)
   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

Comentarios

Para determinar la relación de la instancia actual con value, el CompareTo método compara la Ticks propiedad de la instancia actual y value omite su Kind propiedad. Antes de DateTime comparar objetos, asegúrese de que los objetos representan horas en la misma zona horaria. Para ello, compare los valores de sus Kind propiedades.

Este método implementa la System.IComparable<T> interfaz y funciona ligeramente mejor que la sobrecarga del DateTime.CompareTo(Object) método porque no tiene que convertir el value parámetro en un objeto.

Consulte también

• Compare(DateTime, DateTime)
• Equals(Object)

Source:

DateTime.cs

Source:

DateTime.cs

Source:

DateTime.cs

public:
 virtual int CompareTo(System::Object ^ value);

public:
 int CompareTo(System::Object ^ value);

public int CompareTo (object? value);

public int CompareTo (object value);

abstract member CompareTo : obj -> int
override this.CompareTo : obj -> int

member this.CompareTo : obj -> int

Public Function CompareTo (value As Object) As Integer

Parámetros

Devoluciones

Número con signo que indica los valores relativos de esta instancia y value.

Implementaciones

Excepciones

Ejemplos

En el siguiente ejemplo se muestra el CompareTo método.

using namespace System;
void main()
{
   

   System::DateTime theDay(System::DateTime::Today.Year,7,28);
   int compareValue;
   try
   {
      compareValue = theDay.CompareTo( System::DateTime::Today );
   }
   catch ( ArgumentException^ ) 
   {
      System::Console::WriteLine( "Value is not a DateTime" );
      return;
   }

   if ( compareValue < 0 )
   {
      System::Console::WriteLine( "{0:d} is in the past.", theDay );
   }
   else
   if ( compareValue == 0 )
   {
      System::Console::WriteLine( "{0:d} is today!", theDay );
   }
   else
   // compareValue > 0 
   {
      System::Console::WriteLine( "{0:d} has not come yet.", theDay );
   }
}

open System

let theDay = DateTime(DateTime.Today.Year, 7, 28)

try
    let compareValue = theDay.CompareTo DateTime.Today

    if compareValue < 0 then
        printfn $"{theDay:d} is in the past."
    elif compareValue = 0 then
        printfn $"{theDay:d} is today!"
    else // compareValue > 0
        printfn $"{theDay:d} has not come yet."
        
with :? ArgumentException ->
    Console.WriteLine("Value is not a DateTime");

System.DateTime theDay = new System.DateTime(System.DateTime.Today.Year, 7, 28);
int compareValue;

try
{
    compareValue = theDay.CompareTo(DateTime.Today);
}
catch (ArgumentException)
{
   Console.WriteLine("Value is not a DateTime");
   return;
}

if (compareValue < 0)
   System.Console.WriteLine("{0:d} is in the past.", theDay);
else if (compareValue == 0)
   System.Console.WriteLine("{0:d} is today!", theDay);
else // compareValue > 0
   System.Console.WriteLine("{0:d} has not come yet.", theDay);

Dim thDay As New System.DateTime(System.DateTime.Today.Year, 7, 28)

Dim compareValue As Integer
Try
   compareValue = thDay.CompareTo(System.DateTime.Today)
Catch exp As ArgumentException
   System.Console.WriteLine("Value is not a DateTime")
End Try

If compareValue < 0 Then
   System.Console.WriteLine("{0:d} is in the past.", thDay)
ElseIf compareValue = 0 Then
   System.Console.WriteLine("{0:d} is today!", thDay)
Else   ' compareValue >= 1 
   System.Console.WriteLine("{0:d} has not come yet.", thDay)
End If

Comentarios

Para determinar la relación de la instancia actual con value, el CompareTo método compara la Ticks propiedad de la instancia actual y value omite su Kind propiedad. Antes de DateTime comparar objetos, asegúrese de que los objetos representan horas en la misma zona horaria. Para ello, compare los valores de sus Kind propiedades.

Cualquier instancia de DateTime, independientemente de su valor, se considera mayor que null.

Consulte también

• Compare(DateTime, DateTime)
• Equals(Object)