ช่วยด้วยค้าบ ! ติดปัญหาการเอาข้อมูลเก็บใส่ DB มือใหม่หัดใช้ Sql บน C#

using System.Data.SqlClient;

namespace Project_Pm2
{
    public partial class frmRegister : Form
    {
        public frmRegister(string ID)
        {
            InitializeComponent();
            txtId.Text = ID;
        }

        private void frmRegister_Load(object sender, EventArgs e)
        {
            connectDB();
            reDataGrid();
            SqlCommand comm = new SqlCommand("Select * From location order by locate_id", conn);
            SqlDataReader dr = comm.ExecuteReader();
            DataTable dt = new DataTable();
            dt.Load(dr);
            txtcusLocate.DataSource = dt;
            txtcusLocate.DisplayMember = "locate_name";
         
            
            
        }
        private SqlConnection conn;
        private void connectDB()
        {
            string conStr = "Data Source = BIGGEST-PC; Initial Catalog = db_motorcycle; User = user1; Password = 1234 ";
            conn = new SqlConnection();
            conn.ConnectionString = conStr;
            if (conn.State == ConnectionState.Open)
            { conn.Close(); }
            conn.Open();

        }

        private void reDataGrid()
        {
            //SqlConnection conn = new SqlConnection("Data Source = localhost; Initial Catalog = student_db; user = user1; Password = 1234;");
            SqlDataAdapter dap = new SqlDataAdapter("select * from test1", conn);
            DataSet ds = new DataSet();
            dap.Fill(ds, "cus");
            DataTable dt = ds.Tables["cus"];
            dataGridView1.DataSource = ds;
            dataGridView1.DataMember = "cus";
            dataGridView1.Columns[0].HeaderText = "รหัสลูกค้า";
            dataGridView1.Columns[1].HeaderText = "ชื่อ-นามสกุล";
            dataGridView1.Columns[2].HeaderText = "รหัสบัตรประชาชน";
            dataGridView1.Columns[3].HeaderText = "วันเกิด";
            
            
            
            
        }

        private void insertBT_Click(object sender, EventArgs e)
        {
            connectDB();
            SqlCommand comm = new SqlCommand();
            comm.Connection = conn;

            comm.CommandText = "Insert into custome values (@Pname,@Pidcard,@Pdate,@Paddr,@Pdist,@Pcounty,@Plocate)";
            comm.Parameters.Add("@Pname", SqlDbType.VarChar).Value = txtCusname.Text;
            comm.Parameters.Add("@Pidcard", SqlDbType.VarChar).Value = txtcusIdcard.Text;
            comm.Parameters.Add("@Pdate", SqlDbType.Date).Value = txtcusDate.Text;
            comm.Parameters.Add("@Paddr", SqlDbType.VarChar).Value = txtcusAdress.Text;
            comm.Parameters.Add("@Pdist", SqlDbType.VarChar).Value = txtcusDistrict.Text;
            comm.Parameters.Add("@Pcounty", SqlDbType.VarChar).Value = txtcusCounty.Text;
            comm.Parameters.Add("@Plocate", SqlDbType.Int).Value = txtcusLocate.Text;
            
            int numRec = comm.ExecuteNonQuery();
            if (numRec > 0)
            {
                MessageBox.Show("เพิ่มข้อมูลเรียบร้อยแล้ว");
            }
            else
            {
                MessageBox.Show("ไม่สามารถเพิ่มข้อมูลได้");
            }
            reDataGrid();
        }

        private void txtcusDatePicker_ValueChanged(object sender, EventArgs e)
        {
            txtcusDate.Text = txtcusDatePicker.Value.ToLongDateString();
        }

        private void txtcusRegdatePicker_ValueChanged(object sender, EventArgs e)
        {
            txtcusRegdate.Text = txtcusRegdatePicker.Value.ToLongDateString();
        }

        

        
    }
}