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;



namespace WindowsFormsApplication7

{

    public partial class Form1 : Form

    {

        public enum CalcuType

        {

            None,

            /// <summary>

            /// 加法

            /// </summary>

            Addition,

            /// <summary>

            /// 减法

            /// </summary>

            Substraction,

            /// <summary>

            /// 乘法

            /// </summary>

            Multiplication,

            /// <summary>

            /// 除法

            /// </summary>

            Division,

            /// <summary>

            /// 乘方

            /// </summary>

            Involution,

            /// <summary>

            /// 开方

            /// </summary>

            Square,

        }

        private double? _ValueF =null;//表示可为数字或者null

        private double? _ValueL =null;

        private CalcuType _CalulateType = CalcuType.None;

        private bool _isNew = false;

        string numberStr;

        public Form1()

        {

            InitializeComponent();

        }



        p