[混编] vb如何向fortran传递参数(参数是函数)？

function f(x)
  f=sin(x)+x
end function

Public Class Form1
    Private Declare Sub exdll Lib " d1.dll" (ByVal a As Integer, ByVal b As Integer, ByVal c As pro1)
    Delegate Sub pro1(ByRef a As Integer, ByRef b As Integer)
    Private Sub pro(ByRef a As Integer, ByRef b As Integer)
        Dim c As Integer
        c = a * b
        Debug.Print(c)
        MsgBox(c.ToString)
    End Sub
    Private Sub Button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button4.Click
        Dim x, y As Integer
        x = 2
        y = 5
        Call exdll(x, y, AddressOf pro)
    End Sub

End Class

!Fortran代码：

subroutine exdll(x,y,bkpro)

        !DEC$ ATTRIBUTES stdcall,DLLEXPORT :: exdll
        !DEC$ ATTRIBUTES alias : "exdll" :: exdll
        !DEC$ ATTRIBUTES value :: x,y
        !DEC$ ATTRIBUTES reference :: bkpro

        integer(4) x,y,a,b
        interface
                subroutine bkpro(a,b)
                  integer(4) a,b
                end subroutine
        end interface

        a=x+1
        b=y+1
        call bkpro(a,b)
end subroutine exdll