Почему не выводит базу данных в dataGridView?

using System;
 
using System.Collections.Generic;
 
using System.ComponentModel;
 
using System.Data;
 
using System.Drawing;
 
using System.Linq;
 
using System.Text;
 
using System.Threading.Tasks;
 
using System.Windows.Forms;
 
using System.Data.SqlClient;
 
 
 
namespace New_employment_center
 
{
 
    public partial class Form4 : Form
 
    {
 
        public Form4()
 
        {
 
            InitializeComponent();
 
        }
 
        //global variables
 
        SqlConnection sqlconnection;
 
        SqlCommand sqlcommand;
 
        string ConnectionString = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=C:\Users\min30\source\repos\New employment center\New employment center\Database1.mdf;Integrated Security=True";
 
        string Query;
 
        DataSet dataset;
 
        DataTable datatable;
 
        SqlDataAdapter sqladapter;
 
 
 
 
 
 
 
        //This is the form load event
 
        private void Form4_Load(object sender, EventArgs e)
 
        {
 
            //form load event here data will show in the data gridview
 
            sqlconnection = new SqlConnection(ConnectionString);
 
            Query = "select * from Vacancies";
 
            sqlcommand = new SqlCommand(Query, sqlconnection);
 
            sqladapter = new SqlDataAdapter();
 
            datatable = new DataTable();
 
            sqladapter.SelectCommand = sqlcommand;
 
            sqladapter.Fill(datatable);
 
            dataGridView1.DataSource = datatable;
 
        }
 
 
 
 
 
        //This is the textchanged event    
 
        private void textBox1_TextChanged(object sender, EventArgs e)
 
        {
 
            //textchanged event of texbox when user enter a word in the textbox then through this dataview object string format it will filter and attached the filter result in to the datagridview
 
            DataView DV = new DataView(datatable);
 
            DV.RowFilter = string.Format("Name LIKE '%{0}%'", textBox1.Text);
 
            dataGridView1.DataSource = DV;
 
        }
 
    }
 
}