尝试让 VB 匿名方法正常工作。查询列表

Question

我正在尝试让我的代码按照 http://www.paulstovell.com 上的说明运行/vb-anonymous-methods

到目前为止，我有包装器：

Public Delegate Function PredicateWrapperDelegate(Of T, A)(ByVal item As T, ByVal argument As A) As Boolean
Public Class PredicateWrapper(Of T, A)
    Private _argument As A
    Private _wrapperDelegate As PredicateWrapperDelegate(Of T, A)

    Public Sub New(ByVal argument As A, _
         ByVal wrapperDelegate As PredicateWrapperDelegate(Of T, A))
        _argument = argument
        _wrapperDelegate = wrapperDelegate
    End Sub

    Private Function InnerPredicate(ByVal item As T) As Boolean
        Return _wrapperDelegate(item, _argument)
    End Function

    Public Shared Widening Operator CType( _
        ByVal wrapper As PredicateWrapper(Of T, A)) _
       As Predicate(Of T)
        Return New Predicate(Of T)(AddressOf wrapper.InnerPredicate)
    End Operator
End Class

然后我有我已修改为使用我的部门 id 变量（did）的函数

 Function DidMatch(ByVal item As ListDataItem, ByVal did As Integer) As Boolean
        Return item.AssigneddepartmentID.Equals(did)
    End Function

然后我尝试从我的代码中调用它：

Dim children As List(Of String) = toplevel.FindAll(New PredicateWrapper(Of Integer, Integer)(Did, AddressOf DidMatch))

然后我收到错误在 DidMatch ... 错误方法“公共函数 DidMatch(item As DeptMenuData, did As Integer) As Boolean”没有与委托兼容的签名“委托函数 PredicateWrapperDelegate(Of Integer, Integer)(item As Integer, argument As Integer)”作为布尔值'。

你能看到我做错了什么吗？

谢谢。

Answer 1

更改：

Dim children As List(Of String) = toplevel.FindAll(New PredicateWrapper(Of Integer, Integer)(Did, AddressOf DidMatch))

至：

Dim children As List(Of String) = toplevel.FindAll(New PredicateWrapper(Of ListDataItem, Integer)(Did, AddressOf DidMatch))