Datagridview not filling with DataTable records

Total newbie. 2 weeks into learning C#

I have a successful query that returns 3 rows in my test table.

But am unable to insert them into my datagridview

Form comes up blank every time. (this function is called in Form_Load)

This will be a generic form filled with various columns depending on what the user is looking for.

private void BindGrid()
        {
            string constring= @"Data Source=WIN10\SQLEXPRESS;";
            constring = constring + "Initial Catalog=PLV;";
            constring = constring + "User id=PLV;";
            constring = constring + "Password=PLV;";
            
            DataTable dt = new DataTable();

            using (SqlConnection con = new SqlConnection(constring))
            {
                using (SqlCommand com = new SqlCommand())
                {
                    com.CommandText = "SELECT PrmtNumb, PrmtTNum,NameNumb,ProjDesc FROM dbo.prmtmain WITH(Index(PrmtTNum)) WHERE PrmtNumb = @numb";                  
                    com.Connection = con;

                    using (SqlDataAdapter adapter = new SqlDataAdapter(com))
                    {                        
                        con.Open();
                        adapter.SelectCommand.Parameters.Add(new SqlParameter("@numb", app.answer));
                        adapter.Fill(dt);
                        int cnt = dt.Rows.Count;

                        // cnt = 3 which is correct

                        DataRow[] result = dt.Select("PrmtNumb > 0");

                        // this foreach shows each record correctly.

                        foreach (DataRow row in result)
                        {
                            Console.WriteLine("{0}, {1}", row[0], row[1]);
                        }
                        dataGridView1.DataSource = dt;                       
                    }
                }
               
            }
        }

    }
}

I suspect there is some setting in the Designer I am missing?

Any ideas/suggestions will be greatly appreciated.