Prevent Blank Windows Form DataGridView Row to insert in Database using C#

I'm importing excel file in to datagrid and then i'm inserting it in to database. Problem is excel blank rows are also getting inserted in to database.

        private void btnChooseFile_Click(object sender, EventArgs e)
        {
            string filePath = string.Empty;
            string fileExt = string.Empty;
            OpenFileDialog file = new OpenFileDialog(); //open dialog to choose file
            if (file.ShowDialog() == System.Windows.Forms.DialogResult.OK) //if there is a file choosen by the user
            {
                filePath = file.FileName; //get the path of the file
                fileExt = Path.GetExtension(filePath); //get the file extension
                if (fileExt.CompareTo(".xls") == 0 || fileExt.CompareTo(".xlsx") == 0)
                {
                    try
                    {
                        DataTable dtExcel = new DataTable();
                        dtExcel = ReadExcel(filePath, fileExt); //read excel file
                        dataGridView1.Visible = true;
                        dataGridView1.DataSource = dtExcel;
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.Message.ToString());
                    }
                }
                else
                {
                    MessageBox.Show("Please choose .xls or .xlsx file only.", "Warning", MessageBoxButtons.OK, MessageBoxIcon.Error); //custom messageBox to show error
                }
            }
        }
 
        private void btnClose_Click(object sender, EventArgs e)
        {
            for(int i = 0; i < dataGridView1.Rows.Count; i++)
            {
                string val = this.dataGridView1.Rows[i].Cells[0].Value as string;
                if (string.IsNullOrEmpty(val) == false)
                {
                    con = new SqlConnection(constring);
                    con.Open();
                    cmd = new SqlCommand();
                    cmd.Connection = con;
                    cmd.CommandText = "insert into Barcode(PartNumber, Description, Quantity, Bdate, Location, Mrp, ParentModel) values('" + dataGridView1.Rows[i].Cells[0].Value + "', '" + dataGridView1.Rows[i].Cells[1].Value + "', '" + dataGridView1.Rows[i].Cells[2].Value + "', '" + dataGridView1.Rows[i].Cells[3].Value + "', '" + dataGridView1.Rows[i].Cells[4].Value + "', '" + dataGridView1.Rows[i].Cells[5].Value + "', '" + dataGridView1.Rows[i].Cells[6].Value + "')";
                    cmd.ExecuteNonQuery();
                    con.Close();
                }
                else
                {
                    //this.dataGridView1.Rows[i].Cells[0].Visible = false;
                    MessageBox.Show("Some of the contents of this excel files are empty!");
                }
            }
            MessageBox.Show("Part Details Uploaded Successfully!");
        }