本文整理匯總了VB.NET中System.Nullable<T>.GetValueOrDefault方法的典型用法代碼示例。如果您正苦於以下問題：VB.NET Nullable<T>.GetValueOrDefault方法的具體用法？VB.NET Nullable<T>.GetValueOrDefault怎麽用？VB.NET Nullable<T>.GetValueOrDefault使用的例子？那麽, 這裏精選的方法代碼示例或許可以為您提供幫助。您也可以進一步了解該方法所在類System.Nullable<T>的用法示例。
在下文中一共展示了Nullable<T>.GetValueOrDefault方法的1個代碼示例，這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚，您的評價將有助於係統推薦出更棒的VB.NET代碼示例。
示例1: Sample
' 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輸出：
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]