c#创建文件关联

try
                {
                    string MyFileName = AppSetter.SysInfoPath + @"\DrawTools\csg.exe";
                    string MyExtName = ".csg";
                    string MyType = "csgfile";
                    RegistryKey key = Registry.ClassesRoot.OpenSubKey(MyExtName);
                    if (key == null || key.ValueCount == 0)
                    {
                        RegistryKey MyReg = Registry.ClassesRoot.CreateSubKey(MyExtName);
                        MyReg.SetValue("", MyType);
                        MyReg = MyReg.CreateSubKey("shell\\open\\command");
                        MyReg.SetValue("", MyFileName + " %1");
                        MyReg.Close();
                    }
                    else if (!key.GetValue("").ToString().Equals(MyType))
                    {
                        key.DeleteSubKeyTree(MyExtName);
                        RegistryKey MyReg = Registry.ClassesRoot.CreateSubKey(MyExtName);
                        MyReg.SetValue("", MyType);
                        MyReg = MyReg.CreateSubKey("shell\\open\\command");
                        MyReg.SetValue("", MyFileName + " %1");
                        MyReg.Close();
                    }
                }
                catch (Exception ex)
                {
                    Tools.Trace("Program:Main error:" + ex.ToString());
                }