小弟求教 问什么gridControl总是连接不上数据库 （附图）

using System;
using System.Collections.Generic;
using using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Configuration;
using System.Data.SqlClient;



namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }





 

        //连接字符串 获取配置文件里的连接路径
        static string connStr = ConfigurationManager.ConnectionStrings["str"].ConnectionString;

        
        
        
        
        
        
        //查看并刷新所有数据
      //  private void btnView_Click(object sender, EventArgs e)
     //   {
      //      string sql = "select Id,Movie_Name,Movie_Director,Date_Released from Record";
      //      SqlConnection conn = new SqlConnection(connStr);
         //   SqlCommand cmd = new SqlCommand(sql, conn);
        //    DataTable dt = new DataTable();
         //   SqlDataAdapter sda = new SqlDataAdapter(cmd);
         //   sda.Fill(dt);
          //  gridControl1.DataSource = dt;
       // }

 







        //当系统加载的时候自动显示DataGridView的数据
        private void Form1_Load(object sender, EventArgs e)
        {
            string sql = "select Id,Market_GoodsName,Market_GoodsFactory,Date_Released from Record";
            SqlConnection conn = new SqlConnection(connStr);
            SqlCommand cmd = new SqlCommand(sql, conn);
            DataTable dt = new DataTable();
            SqlDataAdapter sda = new SqlDataAdapter(cmd);
            sda.Fill(dt);
            gridControl1.DataSource = dt;
        }



        
        
        
        
        
        //将鼠标点击的datagridview 上的行内容传递给 文本框
     //   private void Form1_CellContentClick(object sender, DataGridViewCellEventArgs e)
     //   {
            //获取字段名为Movie_Name的单元格内容
         //   txtName.Text = gridControl1.Rows[e.RowIndex].Cells["Movie_Name"].Value.ToString();
            //同理 获取当前点击行里的 name属性为Movie_Director的单元格 获取并将其传至txtDirector 文本框
         //   txtFactory.Text = gridControl1.Rows[e.RowIndex].Cells["Movie_Director"].Value.ToString();
            //new一个时间对象 目的是将电影发行时间的小时,分和秒给去掉 保留到最小单位为日
         //   DateTime datetoDay = new DateTime().Date;
            //将当前行的日期单元格的值 赋给 时间对象datetoDay
         //   datetoDay = Convert.ToDateTime(gridControl1.Rows[e.RowIndex].Cells["Date_Released"].Value);
            //通过ToShortDateString()方法 将日期后的00:00:00 给剔除掉 并赋给 txtDate文本框
         //   txtDate.Text = datetoDay.ToShortDateString();
      //  }


    }
}