新手求前辈指点-- 关于VB.NET 接收短信问题

Question

通过短信猫收到的信息被存储在了sim卡里，如下 (SM 代表sim卡；后面的数字代表存储的位置，叫Index Number) 

+CMTI: "SM",28 

+CMTI: "SM",29 

+CMTI: "SM",30 

下面是接收部分的源码 



   









'--Event handler for the dataReceived event-- 
    Private Sub DataReceived(ByVal sender As Object, _ 
        ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) _ 
        Handles serialPort.DataReceived 

        '---invoke the delegate to retrieve the received data--- 
        txtDataReceived.BeginInvoke(New  _ 
        myDelegate(AddressOf updateTextBox), _ 
        New Object() {}) 
    End Sub 
    '---Delegate and subroutine to update the TextBox control--- 
    Public Delegate Sub myDelegate() 
    Public Sub updateTextBox() 

        '---append the received data into the TextBox control--- 
        With txtDataReceived 
            .AppendText(serialPort.ReadExisting) 
            .ScrollToCaret() 
        End With 
    
    End Sub 

请问如何在这段源码里面制作一个类似装载Index Number的载体  然后利用AT+CMGR="Index Number" 来读取信息  谢谢