Adding a row to a datagridview when using an EDM

Hello Community,

How to add a blank row to my datagridview when I click the button btnAdd? My project below is using an Entity Data Model. I've tried datagridview.Rows.Add(); but result with the following error... "Additional information: Rows cannot be programmatically added to the DataGridView's rows collection when the control is data-bound".  

I am new with C# and any help would be greatly appreciated. Thank you!

public partial class frmMain : Form
    {
        RTCTrialEntities db;        

        public string currenttable { get; set; }
        public int currentindex { get; set; }
        
        public string rtcpntext { get; set; }
        public string descriptiontext { get; set; }
        public string keyvaluetext { get; set; }

        string SelectedTable;
        int MaxRows = 0;
        int Inc = 0;
        bool IndexStatus = true;

        public frmMain()
        {
            InitializeComponent();            
        }
        
        private void Main_Load(object sender, EventArgs e)
        {
            // Creates new instance of the database
            db = new RTCTrialEntities();                        
            
            RecordUpdates();
        }        

        private void cbxTables_SelectedIndexChanged(object sender, EventArgs e)
        {
            // Selected table text from combobox          
            SelectedTable = cbxTables.Text;

            // Populate datagridview
            TableSwitch();
        }

        private void TableSwitch()
        {            
            // Select table to view in the datagrid
            switch (SelectedTable)
            {
                case "Resistors":
                    {
                        dataGridView1.DataSource = db.Resistors.ToList();                                                
                        break;
                    }
                case "Capacitors":
                    {
                        dataGridView1.DataSource = db.Capacitors.ToList();                        
                        break;
                    }
                case "Symbols":
                    {
                        dataGridView1.DataSource = db.Symbols.ToList();                        
                        break;
                    }
                default:
                    {
                        break;
                    }                    
            }
            // Record index status
            if (IndexStatus == true)
            {
                Inc = 0;
            }
            else
            {
                Inc = this.currentindex;
            }
            // Navigates record position
            NavigateRecords();                     
            // Enable navigation buttons
            btnNext.Enabled = true;
            btnPrevious.Enabled = true;
            btnFirst.Enabled = true;
            btnLast.Enabled = true;
        }        

        private void NavigateRecords()
        {
            
            // Clear selected record and select new record
            dataGridView1.ClearSelection();
            dataGridView1.Rows[Inc].Selected = true;
            
            //Counts max records
            MaxRows = dataGridView1.RowCount;
            
            // Update record label
            lblCount.Text = "Record " + (Inc + 1) + " of" + MaxRows;
        }

        public void RecordUpdates()
        {
            // Current Index
            IndexStatus = false;
            
            // Sets current selected table            
            cbxTables.Text = this.currenttable;                                    
            
            // Sets values to datagridview
            dataGridView1.SelectedCells[1].Value = this.rtcpntext;
            dataGridView1.SelectedCells[2].Value = this.descriptiontext;
            dataGridView1.SelectedCells[3].Value = this.keyvaluetext;
            
            // Saves updates to database
            db.SaveChanges();
            
            // Reset index
            IndexStatus = true;
        }

        private void dataGridView1_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            // Updates record position upon cell click
            Inc = dataGridView1.CurrentCell.RowIndex;
            NavigateRecords();
        }

        private void btnNext_Click(object sender, EventArgs e)
        {

            // Increment records
            if (Inc != MaxRows - 1)
            {
                Inc++;
            }
            else
            {
                if (Inc != 0)
                {
                    Inc = 0;
                }
            }
                NavigateRecords();            
        }    
        private void btnPrevious_Click(object sender, EventArgs e)
        {
            // Decrement records
            if (Inc > 0)
            {
                Inc--;                
            }
            else
            {
                if (Inc != MaxRows - 1)
                {
                    Inc = MaxRows - 1;                    
                }                
            }
            NavigateRecords();
        }

        private void btnFirst_Click(object sender, EventArgs e)
        {
            // Jump to first record
            if (Inc != 0)
            {
                Inc = 0;                
            }
            NavigateRecords();
        }

        private void btnLast_Click(object sender, EventArgs e)
        {
            // Jump to last record
            if (Inc != MaxRows - 1)
            {
                Inc = MaxRows - 1;                
            }
            NavigateRecords();
        }

        private void btnClose_Click(object sender, EventArgs e)
        {
            // Close Application
            this.Close();
            Application.Exit();
            
        }

        private void btnEdit_Click(object sender, EventArgs e)
        {
            // Creates new instance of Edit form
            frmEdit EditForm = new frmEdit();            
            
            // Send variables to Edit form
            EditForm.EditDB = db;
            EditForm.EditDGV = dataGridView1;
            EditForm.EditSelectedTable = SelectedTable;
            EditForm.RefToMainForm = this;
            EditForm.EditInc = Inc;

            // Hides form            
            this.Visible = false;

            // Displays Edit form
            EditForm.ShowDialog();
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {            
            
            
            
        }               
    }