本文整理匯總了VB.NET中System.Nullable<T>結構體的典型用法代碼示例。如果您正苦於以下問題：VB.NET Nullable<T>結構體的具體用法？VB.NET Nullable<T>怎麽用？VB.NET Nullable<T>使用的例子？那麽, 這裏精選的結構體代碼示例或許可以為您提供幫助。
在下文中一共展示了Nullable<T>結構體的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
Class Sample
' Define the "titleAuthor" table of the Microsoft "pubs" database.
Public Structure titleAuthor
' Author ID; format ###-##-####
Public au_id As String
' Title ID; format AA####
Public title_id As String
' Author ORD is nullable.
Public au_ord As Nullable(Of Short)
' Royalty Percent is nullable.
Public royaltyper As Nullable(Of Integer)
End Structure
Public Shared Sub Main()
' Declare and initialize the titleAuthor array.
Dim ta(2) As titleAuthor
ta(0).au_id = "712-32-1176"
ta(0).title_id = "PS3333"
ta(0).au_ord = 1
ta(0).royaltyper = 100
ta(1).au_id = "213-46-8915"
ta(1).title_id = "BU1032"
ta(1).au_ord = Nothing
ta(1).royaltyper = Nothing
ta(2).au_id = "672-71-3249"
ta(2).title_id = "TC7777"
ta(2).au_ord = Nothing
ta(2).royaltyper = 40
' Display the values of the titleAuthor array elements, and
' display a legend.
Display("Title Authors Table", ta)
Console.WriteLine("Legend:")
Console.WriteLine("An Author ORD of -1 means no value is defined.")
Console.WriteLine("A Royalty % of 0 means no value is defined.")
End Sub
' Display the values of the titleAuthor array elements.
Public Shared Sub Display(ByVal dspTitle As String, _
ByVal dspAllTitleAuthors() As titleAuthor)
Console.WriteLine("*** {0} ***", dspTitle)
Dim dspTA As titleAuthor
For Each dspTA In dspAllTitleAuthors
Console.WriteLine("Author ID ... {0}", dspTA.au_id)
Console.WriteLine("Title ID .... {0}", dspTA.title_id)
Console.WriteLine("Author ORD .. {0}", dspTA.au_ord.GetValueOrDefault(-1))
Console.WriteLine("Royalty % ... {0}", dspTA.royaltyper.GetValueOrDefault(0))
Console.WriteLine()
Next
End Sub
End Class輸出：
*** Title Authors Table *** Author ID ... 712-32-1176 Title ID .... PS3333 Author ORD .. 1 Royalty % ... 100 Author ID ... 213-46-8915 Title ID .... BU1032 Author ORD .. -1 Royalty % ... 0 Author ID ... 672-71-3249 Title ID .... TC7777 Author ORD .. -1 Royalty % ... 40 Legend: An Author ORD of -1 means no value is defined. A Royalty % of 0 means no value is defined.