Sum up the Values in c#.net

Not sure I am just guessing on this two lines.

tot = Convert.ToDouble(tot + lblTotal.Text);
qty = Convert.ToInt32(qty + txt_Qty.Text);

change it to

tot = tot + Convert.ToDouble(lblTotal.Text);
qty = qty + Convert.ToInt32(txt_Qty.Text);

Hello!
Try below code:

int len = GV_Product.Rows.Count;
double totalValue = 0.0;
int totalQuantity = 0;
bool error = false;
for (int i = 0; i < len; i++)
{
    CheckBox chk = (CheckBox)GV_Product.Rows[i].FindControl("chk");
    Label lblPrdName = (Label)GV_Product.Rows[i].FindControl("lblPrdName");
    Label lblPrdPrice = (Label)GV_Product.Rows[i].FindControl("lblPrdPrice");
    TextBox txt_Qty = (TextBox)GV_Product.Rows[i].FindControl("txt_Qty");
    Label lblTotal = (Label)GV_Product.Rows[i].FindControl("lblTotal");
 
    int price = 0;
    int quantity = 0;

    if (!Int32.TryParse(lblPrdPrice.Text, out price))
    {
        error = true;
    }

    if (!Int32.TryParse(txt_Qty.Text, out quantity))
    {
        error = true;
    }
    if (!error)
    {
        int totalRow = price * quantity;
        totalQuantity += quantity;
        totalValue += totalRow;    

        lblTotal.Text = totalRow.ToString();
    }
    else
    {
        // Display row error or do something else
        lblTotal.Text = "Error!";
    }
}

// You can move code for updating footer fields outside the loop to do it just one time not in every loop course
Label lblGrandTot = (Label)GV_Product.FooterRow.FindControl("lblGrandTot");
Label lblQty = (Label)GV_Product.FooterRow.FindControl("lblQty");
lblGrandTot.Text = totalValue.ToString();
lblQty.Text = totalQuantity.ToString();

My suggestion: Before you convert string to other types you definitelly should checking its value. Use TryParse methods of simple types to check if string is proper value for type.

http://msdn.microsoft.com/pl-pl/library/f02979c7%28v=vs.110%29.aspx[^]

and for parsing double/decimal values refer to this link:
http://stackoverflow.com/questions/1354924/how-do-i-parse-a-string-with-a-decimal-point-to-a-double[^]

Cheers!

Change from

Quote:

tot = Convert.ToDouble(tot + lblTotal.Text);

to

tot = tot + Convert.ToDouble(lblTotal.Text);

and so on.

i want to sumup the GrandtotalAmount(lblGrandTot ) and GrandTotalQty(lblQty) in footerrow(GridView),
when we entering the value in (txt_Qty) ..

Please Help me...

The below code concatenates the (lblTotal.Text),values, suppose 1st val=4 and 2nd val=5 means it shows 45... But i want to add(suppose 1st val=4 and 2nd val=5 means ans should be 9)
The below code concatenates the (txt_Qty .Text),values, suppose 1st val=4 and 2nd val=5 means it shows 45... But i want to add(suppose 1st val=4 and 2nd val=5 means ans should be 9)

This is my code...
int len = GV_Product.Rows.Count;
double tot = 0.0;
int qty = 0;

for (int i = 0; i < len; i++)
{
Label lblPrdPrice = (Label)GV_Product.Rows[i].FindControl("lblPrdPrice");
TextBox txt_Qty = (TextBox)GV_Product.Rows[i].FindControl("txt_Qty");
Label lblQty = (Label)GV_Product.FooterRow.FindControl("lblQty");
Label lblTotal = (Label)GV_Product.Rows[i].FindControl("lblTotal");
Label lblGrandTot = (Label)GV_Product.FooterRow.FindControl("lblGrandTot");





lblTotal.Text = Convert.ToInt32(Convert.ToInt32(txt_Qty.Text) * Convert.ToInt32(lblPrdPrice.Text)).ToString();
tot = Convert.ToDouble(tot + lblTotal.Text);
qty = Convert.ToInt32(qty + txt_Qty.Text);




lblGrandTot.Text = tot.ToString();//This code concatenate the (lblTotal.Text) values, suppose 1st val=4 and 2nd val=5 means it shows 45... But i want to add(suppose 1st val=4 and 2nd val=5 means ans should be 9)
lblQty.Text = qty.ToString();//This code concatenate the (lblTotal.Text) values, suppose 1st val=4 and 2nd val=5 means it shows 45... But i want to add(suppose 1st val=4 and 2nd val=5 means ans should be 9)




}