PKHeX.SAV_Inventory.populateList C# (CSharp) Method

        private void populateList(string[] itemarr, int offset, int itemcount)
        {
            dataGridView1.Rows.Clear();
            dataGridView1.Columns.Clear();

            DataGridViewColumn dgvIndex = new DataGridViewTextBoxColumn();
            {
                dgvIndex.HeaderText = "CNT";
                dgvIndex.DisplayIndex = 1;
                dgvIndex.Width = 45;
                dgvIndex.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleCenter;
            }
            DataGridViewComboBoxColumn dgvItemVal = new DataGridViewComboBoxColumn
            {
                DisplayStyle = DataGridViewComboBoxDisplayStyle.Nothing
            };
            {
                foreach (string t in itemarr)
                    dgvItemVal.Items.Add(t); // add only the Item Names

                dgvItemVal.DisplayIndex = 0;
                dgvItemVal.Width = 135;
                dgvItemVal.FlatStyle = FlatStyle.Flat;
            }
            dataGridView1.Columns.Add(dgvItemVal);
            dataGridView1.Columns.Add(dgvIndex);

            dataGridView1.Rows.Add(itemcount);
            dataGridView1.CancelEdit();

            string itemname = "";
            for (int i = 0; i < itemcount; i++)
            {
                int itemvalue = BitConverter.ToUInt16(sav, offset + i*4);
                try { itemname = Form1.itemlist[itemvalue]; }
                catch
                {
                    Util.Error("Unknown item detected.", "Item ID: " + itemvalue, "Item is after: " + itemname);
                    continue;
                }
                int itemarrayval = Array.IndexOf(itemarr,itemname);
                if (itemarrayval == -1)
                {
                    dataGridView1.Rows[i].Cells[0].Value = itemarr[0];
                    dataGridView1.Rows[i].Cells[1].Value = 0;
                    Util.Alert(itemname + " removed from item pouch.", "If you exit the Item Editor by saving changes, the item will no longer be in the pouch.");
                }
                else
                {
                    dataGridView1.Rows[i].Cells[0].Value = itemarr[itemarrayval];
                    dataGridView1.Rows[i].Cells[1].Value = BitConverter.ToUInt16(sav, offset + i * 4 + 2);
                }
            }
        }
        private void dropclick(object sender, DataGridViewCellEventArgs e)