C#数学运算表达式解释器

測试文件内容：

a=2+3*2;

b=2*(2+3);

浏览按钮事件处理程序：

        private void button_browse_Click(object sender, EventArgs e)

        {

            OpenFileDialog fbd = new OpenFileDialog();

            fbd.Title = "请选择一个文件：";

            fbd.CheckFileExists = true;

            fbd.CheckPathExists = true;

            fbd.Filter = "*.txt(文本文件)|*.txt|*.*(全部文件)|*.*";

            fbd.FileName = Environment.GetFolderPath(Environment.SpecialFolder.MyComputer);

            if (fbd.ShowDialog() == System.Windows.Forms.DialogResult.OK)

            {

                textBox_saveDir.Text = fbd.FileName;

                try

                {

                    FileStream fs = new FileStream(fbd.FileName, FileMode.Open, FileAccess.Read);

                    StreamReader sr = new StreamReader(fs);

                    while (!sr.EndOfStream)

                    {

                        string line = sr.ReadLine();

                        analyse(line);

                    }

                }

                catch (Exception ex)

                {

                    MessageBox.Show("错误：" + ex.Message + "\r\n堆栈：" + ex.StackTrace);

                }

            }

        }

分析一行表达式：

        private void analyse(string line)

        {

            //以分号作为结束符，支持一行内写多个语句

            string[] expA = line.Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);

            for (int i = 0; i < expA.Length; i++)

            {

                analyseExpA(expA[i]);

            }

        }

计算一条表达式：

        private void analyseExpA(string expA)

        {

            string[] expB = expA.Split(new string[] { "=" }, StringSplitOptions.RemoveEmptyEntries);

            for (int i = 0; i < expB.Length; i++ )

            {

                Regex reg = new Regex("[a-zA-Z]");

                if (!reg.IsMatch(expB[i]))

                {

                    object obj = EvalExpress(expB[i]);

                    if (obj != null)

                    {

                        textBox1.Text += expA + " = " + obj.ToString() + "\r\n";

                    }

                    else

                    {

                        textBox1.Text += expA + ",无法识别的表达式\r\n";

                    }

                }

            }

        }

源代码下载：C#数学运算表达式解释器源代码