Nullable<T>.GetValueOrDefault Método

Referencia

Definición

Espacio de nombres:: System

Ensamblado:: System.Runtime.dll

Ensamblado:: mscorlib.dll

Ensamblado:: netstandard.dll

Importante

Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.

Recupera el valor del objeto Nullable<T> actual o un valor predeterminado.

Sobrecargas

GetValueOrDefault()	Recupera el valor del objeto Nullable<T> actual o el valor predeterminado del tipo subyacente.
GetValueOrDefault(T)	Recupera el valor del objeto Nullable<T> actual o el valor predeterminado especificado.

Ejemplos

En el ejemplo de código siguiente se recupera el valor de un Nullable<T> objeto si se define ese valor; de lo contrario, recupera el valor predeterminado o un valor predeterminado específico.

// This code example demonstrates the
// Nullable<T>.GetValueOrDefault methods.

using System;

class Sample
{
    public static void Main()
    {
    float? mySingle = 12.34f;
    float? yourSingle = -1.0f;

   Console.WriteLine("*** Display a value or the default value ***\n");
// Display the values of mySingle and yourSingle.

    Display("A1", mySingle, yourSingle);

// Assign the value of mySingle to yourSingle, then display the values
// of mySingle and yourSingle. The yourSingle variable is assigned the
// value 12.34 because mySingle has a value.

    yourSingle = mySingle.GetValueOrDefault();
    Display("A2", mySingle, yourSingle);

// Assign null (Nothing in Visual Basic) to mySingle, which means no value is
// defined for mySingle. Then assign the value of mySingle to yourSingle and
// display the values of both variables. The default value of all binary zeroes
// is assigned to yourSingle because mySingle has no value.

    mySingle = null;
    yourSingle = mySingle.GetValueOrDefault();
    Display("A3", mySingle, yourSingle);

// Reassign the original values of mySingle and yourSingle.
    mySingle = 12.34f;
    yourSingle = -1.0f;

    Console.Write("\n*** Display a value or the ");
    Console.WriteLine("specified default value ***\n");

// Display the values of mySingle and yourSingle.
    Display("B1", mySingle, yourSingle);

// Assign the value of mySingle to yourSingle, then display the values
// of mySingle and yourSingle. The yourSingle variable is assigned the
// value 12.34 because mySingle has a value.

    yourSingle = mySingle.GetValueOrDefault(-222.22f);
    Display("B2", mySingle, yourSingle);

// Assign null (Nothing in Visual Basic) to mySingle, which means no value is
// defined for mySingle. Then assign the value of mySingle to yourSingle and
// display the values of both variables. The specified default value of -333.33
// is assigned to yourSingle because mySingle has no value.

    mySingle = null;
    yourSingle = mySingle.GetValueOrDefault(-333.33f);
    Display("B3", mySingle, yourSingle);
    }

// Display the values of two nullable of System.Single structures.
// The Console.WriteLine method automatically calls the ToString methods of
// each input argument to display its values. If no value is defined for a
// nullable type, the ToString method for that argument returns the empty
// string ("").
    public static void Display(string title, float? dspMySingle, float? dspYourSingle)
    {
    Console.WriteLine("{0}) mySingle = [{1}], yourSingle = [{2}]",
                      title, dspMySingle, dspYourSingle);
    }
}

/*
This code example produces the following results:

A1) mySingle = [12.34], yourSingle = [-1]
A2) mySingle = [12.34], yourSingle = [12.34]
A3) mySingle = [], yourSingle = [0]

*** Display a value or the specified default value ***

B1) mySingle = [12.34], yourSingle = [-1]
B2) mySingle = [12.34], yourSingle = [12.34]
B3) mySingle = [], yourSingle = [-333.33]

*/

// This code example demonstrates the
// Nullable<T>.GetValueOrDefault methods.
open System

// Display the values of two nullable of System.Single structures.
// The printfn string interpolation automatically calls the ToString methods of
// each input argument to display its values. If no value is defined for a
// nullable type, the ToString method for that argument returns the empty
// string ("").
let display title dspMySingle dspYourSingle =
    printfn $"{title}) mySingle = [{dspMySingle}], yourSingle = [{dspYourSingle}]"

let mySingle = Nullable 12.34f
let yourSingle = Nullable -1f

[<EntryPoint>]
let main _ =
    printfn "*** Display a value or the default value ***\n"
    // Display the values of mySingle and yourSingle.

    display "A1" mySingle yourSingle

    // Shadow the value of mySingle to yourSingle, then display the values
    // of mySingle and yourSingle. The yourSingle variable is assigned the
    // value 12.34 because mySingle has a value.

    let yourSingle = mySingle.GetValueOrDefault()
    display "A2" mySingle yourSingle

    // Shadow null (Nothing in Visual Basic) to mySingle, which means no value is
    // defined for mySingle. Then assign the value of mySingle to yourSingle and
    // display the values of both variables. The default value of all binary zeroes
    // is assigned to yourSingle because mySingle has no value.

    let mySingle = Nullable()
    let yourSingle = mySingle.GetValueOrDefault()
    display "A3" mySingle yourSingle

    // Shadow the original values of mySingle and yourSingle.
    let mySingle = Nullable 12.34f
    let yourSingle = Nullable -1.0f

    printf "\n*** Display a value or the "
    printfn "specified default value ***\n"

    // Display the values of mySingle and yourSingle.
    display "B1" mySingle yourSingle

    // Shadow the value of mySingle to yourSingle, then display the values
    // of mySingle and yourSingle. The yourSingle variable is assigned the
    // value 12.34 because mySingle has a value.

    let yourSingle = mySingle.GetValueOrDefault -222.22f
    display "B2" mySingle yourSingle

    // Shadow null (Nothing in Visual Basic) to mySingle, which means no value is
    // defined for mySingle. Then shadow the value of mySingle to yourSingle and
    // display the values of both variables. The specified default value of -333.33
    // is assigned to yourSingle because mySingle has no value.

    let mySingle = Nullable()
    let yourSingle = mySingle.GetValueOrDefault -333.33f
    display "B3" mySingle yourSingle
    0

// This code example produces the following results:
//     A1) mySingle = [12.34], yourSingle = [-1]
//     A2) mySingle = [12.34], yourSingle = [12.34]
//     A3) mySingle = [], yourSingle = [0]
//     
//     *** Display a value or the specified default value ***
//     
//     B1) mySingle = [12.34], yourSingle = [-1]
//     B2) mySingle = [12.34], yourSingle = [12.34]
//     B3) mySingle = [], yourSingle = [-333.33]

' This code example demonstrates the 
' Nullable(Of T).GetValueOrDefault methods.

Class Sample
    Public Shared Sub Main() 
        Dim mySingle As Nullable(Of System.Single) = 12.34F 
        Dim yourSingle As Nullable(Of System.Single) = - 1.0F 
        
        Console.WriteLine("*** Display a value or the default value ***" & vbCrLf)
    ' Display the values of mySingle and yourSingle.
        Display("A1", mySingle, yourSingle)
        
    ' Assign the value of mySingle to yourSingle, then display the values 
    ' of mySingle and yourSingle. The yourSingle variable is assigned the 
    ' value 12.34 because mySingle has a value.
        yourSingle = mySingle.GetValueOrDefault()
        Display("A2", mySingle, yourSingle)
        
    ' Assign null (Nothing in Visual Basic) to mySingle, which means no value is
    ' defined for mySingle. Then assign the value of mySingle to yourSingle and
    ' display the values of both variables. The default value of all binary zeroes 
    ' is assigned to yourSingle because mySingle has no value.
        mySingle = Nothing
        yourSingle = mySingle.GetValueOrDefault()
        Display("A3", mySingle, yourSingle)
        
    ' Reassign the original values of mySingle and yourSingle.
        mySingle = 12.34F
        yourSingle = - 1.0F
        
        Console.Write(vbCrLf & "*** Display a value or the ")
        Console.WriteLine("specified default value ***" & vbCrLf)
        
    ' Display the values of mySingle and yourSingle.
        Display("B1", mySingle, yourSingle)
        
    ' Assign the value of mySingle to yourSingle, then display the values 
    ' of mySingle and yourSingle. The yourSingle variable is assigned the 
    ' value 12.34 because mySingle has a value.
        yourSingle = mySingle.GetValueOrDefault(- 222.22F)
        Display("B2", mySingle, yourSingle)
        
    ' Assign null (Nothing in Visual Basic) to mySingle, which means no value is
    ' defined for mySingle. Then assign the value of mySingle to yourSingle and
    ' display the values of both variables. The specified default value of -333.33
    ' is assigned to yourSingle because mySingle has no value.
        mySingle = Nothing
        yourSingle = mySingle.GetValueOrDefault(- 333.33F)
        Display("B3", mySingle, yourSingle)
    
    End Sub
     
    
    ' Display the values of two nullable of System.Single structures.
    ' The Console.WriteLine method automatically calls the ToString methods of 
    ' each input argument to display its values. If no value is defined for a
    ' nullable type, the ToString method for that argument returns the empty
    ' string ("").

    Public Shared Sub Display(ByVal title As String, _
                              ByVal dspMySingle As Nullable(Of System.Single), _
                              ByVal dspYourSingle As Nullable(Of System.Single))
        If (True) Then
            Console.WriteLine("{0}) mySingle = [{1}], yourSingle = [{2}]", _
                               title, dspMySingle, dspYourSingle)
        End If
    End Sub
End Class

'
'This code example produces the following results:
'
'A1) mySingle = [12.34], yourSingle = [-1]
'A2) mySingle = [12.34], yourSingle = [12.34]
'A3) mySingle = [], yourSingle = [0]
'
'*** Display a value or the specified default value ***
'
'B1) mySingle = [12.34], yourSingle = [-1]
'B2) mySingle = [12.34], yourSingle = [12.34]
'B3) mySingle = [], yourSingle = [-333.33]
'

GetValueOrDefault()

Source:: Nullable.cs

Source:: Nullable.cs

Source:: Nullable.cs

Recupera el valor del objeto Nullable<T> actual o el valor predeterminado del tipo subyacente.

public:
 T GetValueOrDefault();

public T GetValueOrDefault ();

public readonly T GetValueOrDefault ();

member this.GetValueOrDefault : unit -> 'T

Public Function GetValueOrDefault () As T

Devoluciones

Valor de la Value propiedad si la HasValue propiedad es true; de lo contrario, el valor predeterminado del tipo subyacente.

Comentarios

El GetValueOrDefault método devuelve un valor incluso si la HasValue propiedad es false (a diferencia de la Value propiedad , que produce una excepción). Si la HasValue propiedad es false, el método devuelve el valor predeterminado del tipo subyacente.

Consulte también

GetValueOrDefault(T)

Se aplica a

GetValueOrDefault(T)

Source:: Nullable.cs

Source:: Nullable.cs

Source:: Nullable.cs

Recupera el valor del objeto Nullable<T> actual o el valor predeterminado especificado.

public:
 T GetValueOrDefault(T defaultValue);

public T GetValueOrDefault (T defaultValue);

public readonly T GetValueOrDefault (T defaultValue);

member this.GetValueOrDefault : 'T -> 'T

Public Function GetValueOrDefault (defaultValue As T) As T

Parámetros

defaultValue: T

Valor que se devuelve si la propiedad HasValue es false.

Devoluciones

Valor de la propiedad Value si la propiedad HasValue es true; de lo contrario, el parámetro defaultValue.

Comentarios

El GetValueOrDefault método devuelve un valor incluso si la HasValue propiedad es false (a diferencia de la Value propiedad , que produce una excepción).

Consulte también

GetValueOrDefault()

Se aplica a

Compartir a través de

Nullable<T>.GetValueOrDefault Método

Definición

Sobrecargas

Ejemplos

GetValueOrDefault()

Devoluciones

Comentarios

Consulte también

Se aplica a

GetValueOrDefault(T)

Parámetros

Devoluciones

Comentarios

Consulte también

Se aplica a

Recursos adicionales