我有这段代码，它做了正确的事情，但选择器停留在第一行，所以它增加了错误条目的数量。
我想搜索数据网格，如果第一列有匹配项，则增加 Cells[6].Value(The number of items)，然后使用 Cells[3].Value 中的价格找到总数，然后设置 Cells [6].Value(total) 对这两者的乘积
private void productCodeBox_TextChanged(object sender, EventArgs e)//Event that waits for a correct barcode_id to be entered in
{
string[] itemInfo;//defines a string to hold product information coming in from the API using the getProduct method
int quantity = 1;//sets the initial quantity to 1 as a default
try//tries to parse any input in until a correct product code is entered else carries on checking
{
itemInfo = getProduct(productCodeBox.Text);//initializes the array with the product code that matches a value in the API
foreach (DataGridViewRow row in productList.Rows)//used to check if the item is in the data gridview and adds a qty instead of a whole new item
{
if (row.Cells[0].Value.ToString().Equals(itemInfo[0]))//checks if the product code is already in the datagridview
{
productList.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
//Increments the qty
int qty = (int)productList.Rows[productList.CurrentRow.Index].Cells[6].Value;//gets the current value of the quantity field in the DataGridView at the selected position
productList.Rows[productList.CurrentRow.Index].Cells[6].Value = qty + 1;//Increments the value of the the quantity column in the datagrid view but only the first value.
//Gets the total of that column
double price = (double)productList.Rows[productList.CurrentRow.Index].Cells[3].Value;
double total = price * qty;//calculates the product
productList.Rows[productList.CurrentRow.Index].Cells[7].Value = total;//is meant to get the price from the total column but nothing is displayed
itemInfo = null;//resets the array so that the item is not duplicated
productCodeBox.Clear();//clears the box to wait for the next input
}
}
productList.Rows.Add(new object[] { itemInfo[0], itemInfo[1], itemInfo[2], itemInfo[3], itemInfo[4], itemInfo[5], quantity });//inserts the new value if it does not already exist
productCodeBox.Clear();//clears the text box to wait for more input
}
catch(Exception a)
{
}
}