[C#]Winform下回车或Tab键自动切换下一个控件焦点

/// <summary>
    /// 回车、Tab键盘切换或执行操作
    /// </summary>
   public sealed class TabEnter:IDisposable
    {
       private List<StringBuilder> ml;
       private int i=0;
       private System.Windows.Forms.Control mc;
       /// <summary>
       /// 知否启用Tab键功能
       /// </summary>
       private bool mallowTab=false;
       /// <summary>
       /// 是否启用Tab键切换/执行.
       /// </summary>
       public bool AllowTab
       {
           get { return mallowTab; }
           set { mallowTab = value; }
       }
       public TabEnter(System.Windows.Forms.Control c)
       {
           ml = new List<StringBuilder>();
           mc = c;
       }
       public TabEnter(System.Windows.Forms.Control c, bool allowTab):this(c)
       {
           mallowTab = allowTab;
       }
       public void Add(System.Windows.Forms.Control c)
       {
           c.KeyPress += KeyPressHandler;
           c.TabIndex = i;
           ml.Add(new StringBuilder(c.Name));
           i += 1;
       }
       /// <summary>
       /// 在需要独立处理KeyPress时间时,采用KeyUp来执行,当然可继续实现KeyDown
       /// </summary>
       /// <param name="c"></param>
       public void AddKeyUp(System.Windows.Forms.Control c)
       {
           c.KeyUp += KeyUpHandler;
           c.TabIndex = i;
           ml.Add(new StringBuilder(c.Name));
           i += 1;
       }
       private void KeyPressHandler(object sender, System.Windows.Forms.KeyPressEventArgs e)
       {
           if ((e.KeyChar == (Char)13) || (e.KeyChar == (Char)9 && mallowTab == true))
           {
               int j = ((System.Windows.Forms.Control)sender).TabIndex;
               if (j >= ml.Count - 1) return;
               string cname = ml[j + 1].ToString();
               if (string.IsNullOrEmpty(cname)) return;
               System.Windows.Forms.Control[] tca = mc.Controls.Find(cname, true);
               if (tca == null || tca.Length == 0) return;
               System.Windows.Forms.Control tc = tca[0];
               if (tc == null) return;
               System.Windows.Forms.Button b = tc as System.Windows.Forms.Button;
               if (b != null)
                   b.PerformClick();
               else
                   tc.Focus();
           }
       }
       private void KeyUpHandler(Object sender, System.Windows.Forms.KeyEventArgs e)
       {
           if ((e.KeyCode == System.Windows.Forms.Keys.Enter) || (e.KeyCode == System.Windows.Forms.Keys.Tab && mallowTab == true))
           {
               int j = ((System.Windows.Forms.Control)sender).TabIndex;
               if (j >= ml.Count - 1) return;
               string cname = ml[j + 1].ToString();
               if (string.IsNullOrEmpty(cname)) return;
               System.Windows.Forms.Control[] tca = mc.Controls.Find(cname, true);
               if (tca == null || tca.Length == 0) return;
               System.Windows.Forms.Control tc = tca[0];
               if (tc == null) return;
               if (tc.GetType()==typeof(System.Windows.Forms.Button))
               {
                   ((System.Windows.Forms.Button)tc).PerformClick();
               }
               else
               {
                   if (tc.Visible == true) tc.Focus();
               }

           }
       }
       #region "资源释放"
       public void Dispose()
        {
            Disposing(true);
            GC.SuppressFinalize(this);
        }
        private bool m_disposed = false;
        protected  void Disposing(bool disposing)
        {
            if (!m_disposed)
            {
                if (disposing)
                {
                    //Release managed resources
                    ml.Clear();
                    ml = null;
                    i = 0;
                    mc = null;
                }
                //Release unmanaged Resources
                m_disposed = true;
            }
        }

        ~TabEnter()
        {
            Disposing(false);
        }
       #endregion
    }