Please edit this simple code

private void Form1_Load(object sender, EventArgs e)

{

AddRowsInDatagridView(0,"L", "A", "3", "2");

AddRowsInDatagridView(1,"M", "B", "4", "3");

AddRowsInDatagridView(2,"L", "A", "5", "7");

AddRowsInDatagridView(3,"M", "B", "", "8");

AddRowsInDatagridView(4,"L", "A", "3", "5");

AddRowsInDatagridView(5,"S", "S", "2", "9");

AddRowsInDatagridView(6,"S", "S", "1", "12");

dataGridView2.Visible = false;

}

public void AddRowsInDatagridView(int row,string Type, string Item, string Price, string Qty)

{

dataGridView1.Rows.Add();

dataGridView1.Rows[row].Cells[0].Value = Type;

dataGridView1.Rows[row].Cells[1].Value = Item;

dataGridView1.Rows[row].Cells[2].Value = Price;

dataGridView1.Rows[row].Cells[3].Value = Qty;

}

private void button1_Click(object sender, EventArgs e)

{

dataGridView2.Visible = true;

List _product = new List();

int Count = 1;

foreach (DataGridViewRow row in dataGridView1.Rows)

{

if (row.Cells[0].Value != "" && row.Cells[0].Value != null)

{

if (_product.Where(x => x.Type.ToLower() == row.Cells[0].Value.ToString().ToLower()).Any())

{

string TotalQty = (Convert.ToInt32(_product.Where(x => x.Type.ToLower() == row.Cells[0].Value.ToString().ToLower()).Select(x => x.TotalQty).FirstOrDefault()) + Convert.ToInt32(row.Cells[3].Value.ToString())).ToString();

string TotalPrice = (Convert.ToInt32(_product.Where(x => x.Type.ToLower() == row.Cells[0].Value.ToString().ToLower()).Select(x => x.TotalPrice).FirstOrDefault()) + Convert.ToInt32(row.Cells[2].Value.ToString())).ToString();

_product.Where(x => x.Type.ToLower() == row.Cells[0].Value.ToString().ToLower()).ToList().ForEach(x => { x.TotalQty = TotalQty; x.TotalPrice = TotalPrice; });

}

else

{

_product.Add(new ProductList

{

Sno = Count,

Type = row.Cells[0].Value.ToString(),

Item = row.Cells[1].Value.ToString(),

TotalPrice = row.Cells[2].Value.ToString(),

TotalQty = row.Cells[3].Value.ToString()

});

Count++;

}

}

}

dataGridView2.DataSource = _product;

}