VB.NET Func<TResult>代理代码示例

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本文整理汇总了VB.NET中System.Func<TResult>代理的典型用法代码示例。如果您正苦于以下问题：VB.NET Func<TResult>代理的具体用法？VB.NET Func<TResult>怎么用？VB.NET Func<TResult>使用的例子？那么恭喜您, 这里精选的代理代码示例或许可以为您提供帮助。

在下文中一共展示了Func<TResult>代理的4个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于我们的系统推荐出更棒的VB.NET代码示例。

示例1: Func

Public Module Func
   Public Sub Main()
      ' Note that each lambda expression has no parameters.
      Dim lazyOne As New LazyValue(Of Integer)(Function() ExpensiveOne())
      Dim lazyTwo As New LazyValue(Of Long)(Function() ExpensiveTwo("apple")) 

      Console.WriteLine("LazyValue objects have been created.")

      ' Get the values of the LazyValue objects.
      Console.WriteLine(lazyOne.Value)
      Console.WriteLine(lazyTwo.Value)
   End Sub

   Public Function ExpensiveOne() As Integer
      Console.WriteLine()
      Console.WriteLine("ExpensiveOne() is executing.")
      Return 1
   End Function

   Public Function ExpensiveTwo(input As String) As Long
      Console.WriteLine() 
      Console.WriteLine("ExpensiveTwo() is executing.")
      Return input.Length
   End Function
End Module

Public Class LazyValue(Of T As Structure)
   Private val As Nullable(Of T)
   Private getValue As Func(Of T)

   ' Constructor.
   Public Sub New(func As Func(Of T))
      Me.val = Nothing
      Me.getValue = func
   End Sub

   Public ReadOnly Property Value() As T
      Get
         If Me.val Is Nothing Then
            ' Execute the delegate.
            Me.val = Me.getValue()
         End If   
         Return CType(val, T)
      End Get
   End Property
End Class

开发者ID:VB.NET开发者，项目名称:System，代码行数:46，代码来源:Func

示例2: TestDelegate

' 导入命名空间
Imports System.IO

Delegate Function WriteMethod As Boolean

Module TestDelegate
   Public Sub Main()
      Dim output As New OutputTarget()
      Dim methodCall As WriteMethod = AddressOf output.SendToFile
      If methodCall() Then 
         Console.WriteLine("Success!")
      Else
         Console.WriteLine("File write operation failed.")
      End If      
   End Sub
End Module

Public Class OutputTarget
   Public Function SendToFile() As Boolean
      Try
         Dim fn As String = Path.GetTempFileName
         Dim sw As StreamWriter = New StreamWriter(fn)
         sw.WriteLine("Hello, World!")
         sw.Close      
         Return True
      Catch
         Return False
      End Try
   End Function
End Class

开发者ID:VB.NET开发者，项目名称:System，代码行数:30，代码来源:Func

示例3: TestDelegate

' 导入命名空间
Imports System.IO

Module TestDelegate
   Public Sub Main()
      Dim output As New OutputTarget()
      Dim methodCall As Func(Of Boolean) = AddressOf output.SendToFile
      If methodCall() Then 
         Console.WriteLine("Success!")
      Else
         Console.WriteLine("File write operation failed.")
      End If      
   End Sub
End Module

Public Class OutputTarget
   Public Function SendToFile() As Boolean
      Try
         Dim fn As String = Path.GetTempFileName
         Dim sw As StreamWriter = New StreamWriter(fn)
         sw.WriteLine("Hello, World!")
         sw.Close      
         Return True
      Catch
         Return False
      End Try
   End Function
End Class

开发者ID:VB.NET开发者，项目名称:System，代码行数:28，代码来源:Func

示例4: TestDelegate

' 导入命名空间
Imports System.IO

Module TestDelegate
   Public Sub Main()
      Dim output As New OutputTarget()
      Dim methodCall As Func(Of Boolean) = Function() output.SendToFile()
      If methodCall() Then 
         Console.WriteLine("Success!")
      Else
         Console.WriteLine("File write operation failed.")
      End If      
   End Sub
End Module

Public Class OutputTarget
   Public Function SendToFile() As Boolean
      Try
         Dim fn As String = Path.GetTempFileName
         Dim sw As StreamWriter = New StreamWriter(fn)
         sw.WriteLine("Hello, World!")
         sw.Close      
         Return True
      Catch
         Return False
      End Try
   End Function
End Class

开发者ID:VB.NET开发者，项目名称:System，代码行数:28，代码来源:Func

注：本文中的System.Func<TResult>代理示例整理自Github/MSDocs等源码及文档管理平台，相关代码片段筛选自各路编程大神贡献的开源项目，源码版权归原作者所有，传播和使用请参考对应项目的License；未经允许，请勿转载。