用C#写了一段很简单的代码，想读出D0的值，可以通讯上，为啥读不出值？小弟不是很懂，请各位指导一下。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using AxACTETHERLib;
namespace WindowsFormsApplication2
{
    public partial class Form1 : Form
    {    
        public Form1()
        {
            InitializeComponent();
            object iret;        
            object idata;     
            axActMLQJ71E71TCP1.ActHostAddress = "192.168.0.50 5002";
            iret=axActMLQJ71E71TCP1.GetDevice2("D0",
            out idata);
            idata = textBox1;
        }

        private void Form1_Load(object sender, EventArgs e)
        {     
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {
            //textBox1.ReadOnly = true;//修改属性为只读
        }

        private void button1_Click(object sender, EventArgs e)
        {
            axActMLQJ71E71TCP1.Open();  
        }
        private void button2_Click(object sender, EventArgs e)
        {
            axActMLQJ71E71TCP1.Close();
        }      
    }
}