Question

我必须为这个类创建一个程序，让我调用Multicast Delegate来向后写一个字符串，计算字符数，然后对单词进行计数。我已经解决了所有问题，但是当我运行它时，我得到：System.Reflection.TargetParameterCountException

我昨天才刚刚了解了代表们，所以也许有一些我错过的东西。

Private Delegate Sub Words(ByVal input As String)
    Sub Main()
    Console.Title = "Fun with words"
    Console.WriteLine("Type some words below.")
    Dim Input As String = Console.ReadLine()
    Dim Display As [Delegate]
    Dim Backwards As Words
    Dim Length As Words
    Dim Wordcount As Words
    Backwards = New Words(AddressOf BackwardsFunc)
    Length = New Words(AddressOf LengthFunc)
    Wordcount = New Words(AddressOf WordcountFunc)
    Display = MulticastDelegate.Combine(Backwards, Length, Wordcount)
    Display.DynamicInvoke()

    Console.ReadKey() 'end
End Sub
Sub BackwardsFunc(ByVal Input As String)
    ' Backwards
    Console.Clear()
    Console.ForegroundColor = ConsoleColor.Cyan
    Console.WriteLine(Input)
    Console.ResetColor()
    Console.WriteLine("Backwards:")
    Dim Array() As Char = Input.ToCharArray
    Dim Stack As New Stack()
    For Each element As Char In Array
        Stack.Push(element)
    Next
    For Each element As Char In Stack
        Console.WriteLine(element)
    Next
End Sub
Sub LengthFunc(ByVal Input As String)
    Console.WriteLine()
    Console.WriteLine("Length: " & Input.Length)
End Sub
Sub WordcountFunc(ByVal Input As String)
    Dim Items As String() = Input.Split(New Char() {" "c})
    Console.WriteLine()
    Console.WriteLine("Words: " & Items.Length)
End Sub

Answer 1

您的代理Words需要一个参数，但在您调用代理时不提供参数。

当您调用MulticastDelegate时，还提供委托必须使用的参数，如下所示：

Display.DynamicInvoke(Input)

System.Reflection.TargetParameterCountException

1 个答案: