Я получаю объект error, установленный в экземпляр ссылки проекта объекта - https://drive.google.com/drive/folders/1nu7huhfjgowxc22aptlhlwienyth_lcx-что? УСП=обмен

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 FireSharp.Config;
using FireSharp.Response;
using FireSharp.Interfaces;

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

        IFirebaseConfig fcon = new FirebaseConfig()
        {
            AuthSecret = "NK4r2FbHGqMpmEPfPMgRkmaqOBjEzYeJYCvpmn0q",
            BasePath = "https://cfireeng-6efa8.firebaseio.com/"
        };

        IFirebaseClient client;

        private void Form1_Load(object sender, EventArgs e)
        {
            try 
            {
                client = new FireSharp.FirebaseClient(fcon);
            }
            catch
            {
                MessageBox.Show("there was problem in the internet.");
            }
        }

        private void InsertBtn_Click(object sender, EventArgs e)
        {
            #region store in the studentlist
            Student std = new Student()
            {
                FullName = nameTbox.Text,
                RollNo = rollTbox.Text,
                Grade = gradeTobx.Text,
                Section = secTbox.Text
            };
            var setter = client.Set("StudentList/"+rollTbox.Text,std);
            MessageBox.Show("data inserted successfully");
            #endregion

            //store in sno
            FirebaseResponse res = client.Get(@"Counter");
            int Counter = int.Parse(res.ResultAs<string>());

            MyRoll roll = new MyRoll()
            {
                RollNo = rollTbox.Text
            };

            var set2 = client.Set(@"Counter", ++Counter);
            var set3 = client.Set(@"Sno/" + Counter, roll);

            MessageBox.Show("INSERTED SUCCESSFULLY");
        }

        private void SelectBtn_Click(object sender, EventArgs e)
        {
            var result = client.Get("StudentList/" + rollTbox.Text);
            Student std = result.ResultAs<student>();
            nameTbox.Text = std.FullName;
            gradeTobx.Text = std.Grade;
            secTbox.Text = std.Section;
            MessageBox.Show("data retrieved successfully");
        }

        private void UpdateBtn_Click(object sender, EventArgs e)
        {
            Student std = new Student()
            {
                FullName = nameTbox.Text,
                RollNo = rollTbox.Text,
                Grade = gradeTobx.Text,
                Section = secTbox.Text
            };
            var setter = client.Update("StudentList/" + rollTbox.Text, std);
            MessageBox.Show("data inserted successfully");
        }

        private void DeleteBtn_Click(object sender, EventArgs e)
        {
            var result = client.Delete("StudentList/" + rollTbox.Text);
            MessageBox.Show("data deleted successfully");
        }

        //show all records
        private void button1_Click(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("Full Name");
            dt.Columns.Add("Roll No");
            dt.Columns.Add("Grade");
            dt.Columns.Add("Section");

           
            FirebaseResponse res = client.Get(@"Counter");
            int Counter = int.Parse(res.ResultAs<string>());

            for (int i = 1; i <= Counter; i++)
            {
                FirebaseResponse res2 = client.Get(@"Sno/" + i + "/RollNo");
                string RollNo = res2.ResultAs<string>();

                var res3 = client.Get(@"StudentList/" + RollNo);
                Student std = res3.ResultAs<student>();

                if(1==1) // (std!=null)
                {
                    dt.Rows.Add(std.FullName, std.RollNo, std.Grade, std.Section);
                }
            }

            foreach (DataRow item in dt.Rows)
            {
                dataGridView1.Rows.Add(item.ItemArray);
            }
        }
    }
}

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 FireSharp.Config;
using FireSharp.Response;
using FireSharp.Interfaces;

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

        IFirebaseConfig fcon = new FirebaseConfig()
        {
            AuthSecret = "NK4r2FbHGqMpmEPfPMgRkmaqOBjEzYeJYCvpmn0q",
            BasePath = "https://cfireeng-6efa8.firebaseio.com/"
        };

        IFirebaseClient client;

        private void Form1_Load(object sender, EventArgs e)
        {
            try 
            {
                client = new FireSharp.FirebaseClient(fcon);
            }
            catch
            {
                MessageBox.Show("there was problem in the internet.");
            }
        }

        private void InsertBtn_Click(object sender, EventArgs e)
        {
            #region store in the studentlist
            Student std = new Student()
            {
                FullName = nameTbox.Text,
                RollNo = rollTbox.Text,
                Grade = gradeTobx.Text,
                Section = secTbox.Text
            };
            var setter = client.Set("StudentList/"+rollTbox.Text,std);
            MessageBox.Show("data inserted successfully");
            #endregion

            //store in sno
            FirebaseResponse res = client.Get(@"Counter");
            int Counter = int.Parse(res.ResultAs<string>());

            MyRoll roll = new MyRoll()
            {
                RollNo = rollTbox.Text
            };

            var set2 = client.Set(@"Counter", ++Counter);
            var set3 = client.Set(@"Sno/" + Counter, roll);

            MessageBox.Show("INSERTED SUCCESSFULLY");
        }

        private void SelectBtn_Click(object sender, EventArgs e)
        {
            var result = client.Get("StudentList/" + rollTbox.Text);
            Student std = result.ResultAs<Student>();
            nameTbox.Text = std.FullName;
            gradeTobx.Text = std.Grade;
            secTbox.Text = std.Section;
            MessageBox.Show("data retrieved successfully");
        }

        private void UpdateBtn_Click(object sender, EventArgs e)
        {
            Student std = new Student()
            {
                FullName = nameTbox.Text,
                RollNo = rollTbox.Text,
                Grade = gradeTobx.Text,
                Section = secTbox.Text
            };
            var setter = client.Update("StudentList/" + rollTbox.Text, std);
            MessageBox.Show("data inserted successfully");
        }

        private void DeleteBtn_Click(object sender, EventArgs e)
        {
            var result = client.Delete("StudentList/" + rollTbox.Text);
            MessageBox.Show("data deleted successfully");
        }

        //show all records
        private void button1_Click(object sender, EventArgs e)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("Full Name");
            dt.Columns.Add("Roll No");
            dt.Columns.Add("Grade");
            dt.Columns.Add("Section");

           
            FirebaseResponse res = client.Get(@"Counter");
            int Counter = int.Parse(res.ResultAs<string>());

            for (int i = 1; i <= Counter; i++)
            {
                FirebaseResponse res2 = client.Get(@"Sno/" + i + "/RollNo");
                string RollNo = res2.ResultAs<string>();

                var res3 = client.Get(@"StudentList/" + RollNo);
                Student std = res3.ResultAs<Student>();

                if(1==1) // (std!=null)
                {
                    dt.Rows.Add(std.FullName, std.RollNo, std.Grade, std.Section);
                }
            }

            foreach (DataRow item in dt.Rows)
            {
                dataGridView1.Rows.Add(item.ItemArray);
            }
        }
    }
}