当前函数调用之前的VB.Net Roslyn Insert语句

Question

我正在使用SyntaxWalker浏览树，在下面的函数中，我意识到我需要在我正在处理之前插入一个语句。

Public Overrides Function VisitDeclarationExpression(ByVal Node As CSS.DeclarationExpressionSyntax) As VisualBasicSyntaxNode
    Dim VariableDesignation As CSS.SingleVariableDesignationSyntax = CType(Node.Designation, CSS.SingleVariableDesignationSyntax)
    Dim name As NameColonEqualsSyntax = Nothing
    Dim value As ExpressionSyntax = CType(VariableDesignation.Accept(Me), ExpressionSyntax)
    ' Need to Insert Dim before the statement that contains this SimpleArgument 
    Return SyntaxFactory.SimpleArgument(name, value)
End Function

我需要声明“name = Nothing”，所以我可以在TryGetValue（name）中使用name。在C＃中使用

很容易

return v.TryGetValue(out var name)

但在VB中我需要两个语句

Dim name As Object = Nothing
Return v.TryGetValue(name)

如何将Dim插入到我正在走路的声明之上？