Nullable<(Of <(T>)>).Value Property
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Gets the value of the current Nullable<(Of <(T>)>) value.
Namespace: System
Assembly: mscorlib (in mscorlib.dll)
Syntax
Public ReadOnly Property Value As T
public T Value { get; }
Property Value
Type: T
The value of the current Nullable<(Of <(T>)>) object if the HasValue property is true. An exception is thrown if the HasValue property is false.
Exceptions
Exception | Condition |
---|---|
InvalidOperationException | The HasValue property is false. |
Examples
The following code example returns the value of a Nullable<(Of <(T>)>) object if that object has a defined value; otherwise, a default value is returned.
' This code example demonstrates the Nullable(Of T).HasValue
' and Value properties.
Class Example
Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
Dim myNow As Nullable(Of DateTime)
' Assign the current date and time to myNow then display its value.
myNow = DateTime.Now
Display(outputBlock, myNow, "1) ")
' Assign null (Nothing in Visual Basic) to myNow then display its value.
myNow = Nothing
Display(outputBlock, myNow, "2) ")
End Sub 'Main
' Display the date and time.
Public Shared Sub Display(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal displayDateTime As Nullable(Of DateTime), _
ByVal title As String)
' If the HasValue property for the nullable of DateTime input argument is true,
' display the value of the input argument; otherwise, display that no value is
' defined for the input value.
outputBlock.Text &= title
If displayDateTime.HasValue = True Then
outputBlock.Text += String.Format("The date and time is {0:F}.", displayDateTime.Value) & vbCrLf
Else
outputBlock.Text &= "The date and time is not defined." & vbCrLf
End If
End Sub 'Display
End Class 'Sample '
'This code example produces the following results:
'
'1) The date and time is Tuesday, April 19, 2005 4:16:06 PM.
'2) The date and time is not defined.
'
// This code example demonstrates the Nullable<T>.HasValue
// and Value properties.
using System;
class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
DateTime? myNow;
// Assign the current date and time to myNow then display its value.
myNow = DateTime.Now;
Display(outputBlock, myNow, "1) ");
// Assign null (Nothing in Visual Basic) to myNow then display its value.
myNow = null;
Display(outputBlock, myNow, "2) ");
}
// Display the date and time.
public static void Display(System.Windows.Controls.TextBlock outputBlock, DateTime? displayDateTime, string title)
{
// If a value is defined for the displayDatetime argument, display its value; otherwise,
// display that no value is defined.
outputBlock.Text += title;
if (displayDateTime.HasValue == true)
outputBlock.Text += String.Format("The date and time is {0:F}.", displayDateTime.Value) + "\n";
else
outputBlock.Text += "The date and time is not defined." + "\n";
}
}
/*
This code example produces the following results:
1) The date and time is Tuesday, April 19, 2005 4:16:06 PM.
2) The date and time is not defined.
*/
Version Information
Windows Phone OS
Supported in: 8.1, 8.0, 7.1, 7.0
Platforms
Windows Phone