未将对象引用设置到对象的实例

Question

这个方法会出现“未将对象引用设置到对象的实例”，问题出在哪里了呢？
刚开始学习C#，请大家指教！谢谢
 RegistryKey keycom = Registry.LocalMachine.OpenSubKey("Hardware\\DevinceMap\\SerialComm");
            try
            {
               
                string[] subkeys = keycom.GetValueNames();//????
                
                string[] str_key = new string[subkeys.Length];
                for (int i = 0; i < subkeys.Length; i++)
                {
                   this.comboBox1.Items.Add(str_key[i]);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }
对象C#

Answer 1

设置断点，单步调试，就知道问题出在哪了？keycom这个对象为Null么？

Answer 2

            RegistryKey keycom = Registry.LocalMachine.OpenSubKey("Hardware\\DevinceMap\\SerialComm");
            try
            {
                int leng = keycom.GetValueNames().;
                string[] subkeys = new string[leng + 1];
                subkeys=keycom.GetValueNames();
                
                string[] str_key = new string[subkeys.Length];
                for (int i = 0; i < subkeys.Length; i++)
                {
                   this.comboBox1.Items.Add(str_key[i]);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
                return;
            }

Answer 3

   RegistryKey keycom = Registry.LocalMachine.OpenSubKey("Hardware\\DevinceMap\\SerialComm");
=-------------
 注册表没有这个路劲
   string[] subkeys = keycom.GetValueNames();//????
---------------
    这里获取的时候 subkeys.length为零。

Answer 4

http://www.docin.com/p-103654353.html
路径写错啦，应为RegistryKey keycom = Registry.LocalMachine.OpenSubKey("Hardware\\DeviceMap\\SerialComm");但返回为空，我这是为了读取计算机的串口。。
http://www.docin.com/p-103654353.html