未处理 System.TypeInitializationException Message=""Medecins.类包.SQL"的类型初始值设定项引发异常

Question

SQL类代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
using System.Data;namespace Medecins.类包
{
    class SQL
    {
        public static string conStr = "server=.;database=MZ_doctor;uid=sa;pwd=123";
        public static string connectDB = "server.;database=MZ_doctor;uid=sa;pwd=123";
        public static SqlConnection cn = new SqlConnection(connectDB);
        public static DataSet GetDataFormDB(string sqlStr)
        {
            cn.Open();
            SqlDataAdapter myAdapter = new SqlDataAdapter(sqlStr, cn);
            DataSet myDataSet = new DataSet();
            myDataSet.Clear();
            myAdapter.Fill(myDataSet);
            cn.Close();
            if (myDataSet.Tables[0].Rows.Count != 0)
            {
                return myDataSet;
            }
            else
            {
                return null;
            }
        }
        //“写”数据库的静态方法
        public static bool UpdateDB(string sqlStr)
        {
            cn.Open();
            //定义数据命令对象
            SqlCommand myCmd = new SqlCommand(sqlStr, cn);
            //设置Command对象的CommandType属性
            myCmd.CommandType = CommandType.Text;
            //执行SQL语句
            myCmd.ExecuteNonQuery();
            cn.Close();
            //数据更新成功，返回true
            return true;
        }
    }
}页面代码：
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;
using Microsoft.Internal.Performance;
using System.IO;
using System.Data.SqlClient;
using System.Text.RegularExpressions;//RegEx是Visual Studio .NET中的正则表达式类
using Medecins.类包;namespace Medecins.数据初始化
{
    public partial class 人员管理 : Form
    {
        DataSet ds = new DataSet();        public 人员管理()
        {
            InitializeComponent();
        }
        
        void rfcs()
        {
            string ryxx="select RY_ID AS 工号,RY_XM AS 姓名,RY_JM AS 简码,RY_BM AS 民族 ,RY_XL AS 学历,RY_CSRQ AS 出生日期,RY_SFZH AS 身份证号,RY_GLZW AS 管理职务";            ds = SQL.GetDataFormDB(ryxx);
            if (ds != null)
            {
                dataGridView1.DataSource = ds.Tables[0];
                dataGridView1.Columns[0].HeaderText = "工号";
                dataGridView1.Columns[0].Width = 60;                dataGridView1.DataSource = ds.Tables[0];
                dataGridView1.Columns[1].HeaderText = "姓名";
                dataGridView1.Columns[1].Width = 60;
            }
            else
            {
                dataGridView1.DataSource = null;
            }        }
        #region //数据控件的RowHeaderMouseClick 事件代码
        private void dataGridView1_RowHeaderMouseClick(object sender, DataGridViewCellMouseEventArgs e)
        {
            try
            {
                int n = dataGridView1.CurrentCell.RowIndex;
                if (n > 0 && n < dataGridView1.RowCount - 1)
                {
                    textBox1.Text = this.dataGridView1[0, n].Value.ToString().Trim();
                    textBox2.Text = dataGridView1[1, n].Value.ToString().Trim();
                    textBox3.Text = dataGridView1[2, n].Value.ToString().Trim();
                    textBox4.Text = dataGridView1[3, n].Value.ToString().Trim();
                    textBox5.Text = dataGridView1[4, n].Value.ToString().Trim();
                    textBox6.Text = dataGridView1[5, n].Value.ToString().Trim();
                    textBox7.Text = dataGridView1[6, n].Value.ToString().Trim();
                    textBox8.Text = dataGridView1[7, n].Value.ToString().Trim();
                    textBox9.Text = dataGridView1[8, n].Value.ToString().Trim();
                    
                }            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        #endregion        #region//DataGridView点击触发事件
        private void dataGridView1_CellContentClick_1(object sender, DataGridViewCellEventArgs e)
        {
            try
            {
                //避免选中列标题，报错
                if (e.RowIndex.ToString() != "-1")
                {
                    //单击某一单元格获取当前的行赋于字段值
                    textBox1.Text = dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["工号"].Value.ToString();
                    textBox2.Text = dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["姓名"].Value.ToString();
                     
                    //pictureBox1.Text = dataGridView1.Rows[dataGridView1.CurrentRow.Index].Cells["相片"].Value.ToString();
                }
                if (textBox1.Text.ToString() != "")
                {
                    button4.Enabled = true;
                    
                }
                else
                {
                    button4.Enabled = false;
                   
                }
            }
            catch (Exception)
            {
                MessageBox.Show("操作有误，请检查！", "温馨提示");
            }
        }
        #endregion        #region   增加人员信息
        private void button2_Click(object sender, EventArgs e)
        {
            人员管理_增加人员 add_ry = new 人员管理_增加人员();
            add_ry.Show();        }
        #endregion        private void button1_Click(object sender, EventArgs e)
        {
            try
            {
                string CX=(SQL.connectDB);
                if (textBox10.Text.Trim() == "")
                {
                    MessageBox.Show("请输入需要查询的工号或名称！","提示");
                    return;
                }
                else
                {
                    CX="select RY_ID,RY_Xm from ZD_RY";
                }
                DataSet ds=new DataSet();
                ds=SQL.GetDataFormDB(CX);
                if (ds!=null)
                {
                    dataGridView1.DataSource=ds.Tables[0];
                    dataGridView1.Columns[0].HeaderText="工号";
                    dataGridView1.Columns[0].Width=60;
                   
                }
                else
                {
                    dataGridView1.DataSource=null;
                    MessageBox.Show("错误！");
                }
                
            }
            catch(Exception ex)
            {
                SQL.cn.Close();
                MessageBox.Show(ex.Message);
            }
        }
       
    }
}抛出的异常提示在：DataGridView

Answer 1

抛出异常求高手帮忙解答如何解决，谢谢！