产量换算成VB.NET版

首先,我必须假设我不太熟悉C#yield关键字及其函数。 “翻译”成英语的最好/最简单的方法是什么VB.NET? 尤其是我试图改变信仰 this code

yield return new MatchNode(++index, current.Value);

我得到的是:

Imports System.Collections
Imports System.Data.SqlTypes
Imports System.Diagnostics.CodeAnalysis
Imports System.Text.RegularExpressions
Imports Microsoft.SqlServer.Server

Class MatchNode
    Private _index As Integer
    Private _value As String

    Public Sub New(ByVal index As Integer, ByVal value As String)
        _index = index
        _value = value
    End Sub

    Public ReadOnly Property Index() As Integer
        Get
            Return _index
        End Get
    End Property

    Public ReadOnly Property Value() As String
        Get
            Return _value
        End Get
    End Property

End Class

Class MatchIterator
    Implements IEnumerable

    Private _regex As Regex
    Private _input As String

    Public Sub New(ByVal input As String, ByVal pattern As String)
        MyBase.New()
        _regex = New Regex(pattern, UserDefinedFunctions.Options)
        _input = input
    End Sub

    Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
        Dim index As Integer = 0
        Dim current As Match = Nothing

        While (current Is Nothing OrElse current.Success)
            If current Is Nothing Then
                current = _regex.Match(_input)
            Else
                current = current.NextMatch()
            End If

            If current.Success Then
                index += 1
                'following should be a VB.Net yield'
                Return New MatchNode(index, current.Value)
            End If

        End While
    End Function
End Class

Partial Public Class UserDefinedFunctions

    <SqlFunction(FillRowMethodName:="FillMatchRow", TableDefinition:="[Index] int,[Text] nvarchar(max)")> _
    Public Shared Function RegexMatches(ByVal input As SqlChars, ByVal pattern As SqlString) As IEnumerable
        Return New MatchIterator(New String(input.Value), pattern.Value)
    End Function

    Public Shared Sub FillMatchRow(ByVal data As Object, ByRef index As SqlInt32, ByRef text As SqlChars)
        Dim node As MatchNode = CType(data, MatchNode)
        index = New SqlInt32(node.Index)
        text = New SqlChars(node.Value.ToCharArray)
    End Sub

End Class