本文整理匯總了VB.NET中System.Linq.Queryable.LastOrDefault方法的典型用法代碼示例。如果您正苦於以下問題：VB.NET Queryable.LastOrDefault方法的具體用法？VB.NET Queryable.LastOrDefault怎麽用？VB.NET Queryable.LastOrDefault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。
在下文中一共展示了Queryable.LastOrDefault方法的3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: numbers
Dim numbers() As Double = {49.6, 52.3, 51.0, 49.4, 50.2, 48.3}
' Get the last number in the array that rounds to 50.0,
' or else the default value for type double (0.0).
Dim last50 As Double = _
numbers.AsQueryable().LastOrDefault(Function(n) Math.Round(n) = 50.0)
MsgBox(String.Format("The last number that rounds to 50 is {0}.", last50))
' Get the last number in the array that rounds to 40.0,
' or else the default value for type double (0.0).
Dim last40 As Double = _
numbers.AsQueryable().LastOrDefault(Function(n) Math.Round(n) = 40.0)
MsgBox(String.Format("The last number that rounds to 40 is {0}.", _
IIf(last40 = 0.0, "[DOES NOT EXIST]", last40.ToString())))輸出：
The last number that rounds to 50 is 50.2. The last number that rounds to 40 is [DOES NOT EXIST].
示例2: fruits
' Create an empty array.
Dim fruits() As String = {}
' Get the last item in the array, or else the default
' value for type string (null).
Dim last As String = fruits.AsQueryable().LastOrDefault()
MsgBox(IIf(String.IsNullOrEmpty(last), "[STRING IS NULL OR EMPTY]", last))輸出：
[STRING IS NULL OR EMPTY]
示例3: List
Dim daysOfMonth As New List(Of Integer)(New Integer() {})
' Setting the default value to 1 after the query.
Dim lastDay1 As Integer = daysOfMonth.AsQueryable().LastOrDefault()
If lastDay1 = 0 Then
lastDay1 = 1
End If
MsgBox(String.Format("The value of the lastDay1 variable is {0}", lastDay1))
' Setting the default value to 1 by using DefaultIfEmpty() in the query.
Dim lastDay2 As Integer = daysOfMonth.AsQueryable().DefaultIfEmpty(1).Last()
MsgBox(String.Format("The value of the lastDay2 variable is {0}", lastDay2))輸出：
The value of the lastDay1 variable is 1 The value of the lastDay2 variable is 1