sum of value not showing

Question

dear sir,

i have a gridview in windows application form in that ihave a checkbox for selecting the row and also its contains Amount field

when i select first checkbox in gridview it is not showing the value at label

here is my code:

 

private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)

{

//try

//{

decimal TotalValue = 0.0m;

for (int i = 0; i < dataGridView1.Rows.Count; ++i)

{

if (Convert.ToString(dataGridView1.Rows[i].Cells[0].Value) == "1")

{

TotalValue += decimal.Parse(dataGridView1.Rows[i].Cells[7].Value.ToString());

}

else

{

}

}

lblInvoiceamt.Text = TotalValue.ToString();

//}

//catch (Exception ex)

//{

//}

}