c# OPCUA 编程

        private void btnRead_Click(object sender, EventArgs e)
        {
            try
            {
                NodeIdCollection nodesToRead = new NodeIdCollection();//建立节点集合（变量集合）--保存要读写的所有变量
                DataValueCollection results;                      //建立变量值集合--用来保存读取到的所有变量的所有值（这个值包含状态、实际值等等）

                /*添加3个变量名*/
                NodeId nodeToRead1 = new NodeId("/Channel/Parameter/R[1,3]", 2);//把具体变量名赋给NodeId对象，然后把该对象给 NodeIdCollection（2是siemens固定的）
                NodeId nodeToRead2 = new NodeId("/Channel/Parameter/R[u1,4]", 2);
                NodeId nodeToRead3 = new NodeId("/Channel/ProgramInfo/progName", 2);
                nodesToRead.Add(nodeToRead1);           //把NodeId对象（就是变量的名）追加到 NodeIdCollection集合里 
                nodesToRead.Add(nodeToRead2);
                nodesToRead.Add(nodeToRead3);

                m_Server.ReadValues(nodesToRead, out results); //读取变量值：从nodesToRead集合里把每个变量的值读取出来放到results变量值集合里
                                                               //因为我们只给了一个变量名，所以，实际上results里只有一个对象results[0]
             /*遍历读取 R1/R2/R3*/
                int i = 1;
                foreach (double item in (double[])results[0].Value) //我们读取的是R1~R3三个值，所有results[0].Value实际上是一个数组集合，是double[]
                                                                    //在系统里，results[0].Value是object类型，所以要强转为double[]
                {                  
                    listView1.Items.Add("R" i "=" item.ToString());  //把遍历出来的R1/R2/R3的值 添加到listView1的第二行及该行第1列的值
                    i ;
                }
             /*读取R4*/
                listView1.Items.Add("R4" results[1].Value.ToString());
             /*读取程序名*/
                listView1.Items.Add(results[2].Value.ToString());
                   
            }
            catch (Exception ex)
            {
                MessageBox.Show("Read failed:\n\n" ex.Message);
            }
        }
/// <summary>
/// Write Values
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
    object currentValue;
    private void btnWrite_Click(object sender, EventArgs e)
        {
            //NodeIdCollection nodesToWrite = new NodeIdCollection();//建立节点集合（变量集合）--保存要读写的所有变量
            //DataValueCollection values=new DataValueCollection(); //建立变量值集合--用来保存读取到的所有变量的所有值（这个值包含状态、实际值等等）
            //StatusCodeCollection results;

            ///*添加3个变量名*/
            //NodeId nodeToWrite1 = new NodeId(textBox1.Text, 2);
            //nodesToWrite.Add(nodeToWrite1);
            //NodeId nodeToRead1 = new NodeId(textBox2.Text, 2);
            
        
           object valueToWrite="53"; //要写入的具体值
            StatusCodeCollection results; //状态变量
            try
            {
               //设定要修改的参数
                NodeIdCollection nodesToWrite = new NodeIdCollection();
                NodeId nodeToWrite = new NodeId("/Channel/Parameter/R[u1,3]", 2);
                nodesToWrite.Add(nodeToWrite);      //添加要写的变量
              
                //设定要写入的具体值
                DataValueCollection values = new DataValueCollection();
              //  Variant value = new Variant(Convert.ChangeType(valueToWrite, currentValue.GetType()));//将给定的值string类型转换为要写的这个参数的实际类型
                Variant value = new Variant(true);
                values.Add(new DataValue(value));//添加要写的值               

                m_Server.WriteValues(nodesToWrite, values, out results);

                if (StatusCode.IsBad(results[0]))
                {
                    throw new Exception(StatusCode.LookupSymbolicId(results[0].Code));
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("Writing new value failed:\n\n" ex.Message);
            }
   
        }