Object reference not set to an instance of an object.

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How to solve tgis error in below coding?

Object reference not set to an instance of an object.

C#

public void totalprice()
   {
       int quantity;
       float price;
       float rowtotal ;
       float subtotal=0;
       float totalprice ;
       foreach (GridViewRow row in GridView1.Rows)
       {
           //int pro_id = Convert.ToInt32(GridView1.DataKeys[row.RowIndex][0]);
           quantity = Convert.ToInt32((row.FindControl("quantity")).ToString());
           price = float.Parse((row.FindControl("price")).ToString());
           rowtotal = quantity * price;
           subtotal += rowtotal;
       }

       totalprice = subtotal;
       lbltprice.Text = totalprice.ToString();
   }

Posted 4-Dec-11 20:01pm

sathiyak

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Eduard Lu · Answer 1 · 2011-12-04T20:05:00

Solution 1

This means that you are getting null value in the ff lines:

C#

quantity = Convert.ToInt32((row.FindControl("quantity")).ToString());
price = float.Parse((row.FindControl("price")).ToString());

Use Int32.TryParse or Float.TryParse method instead. This is safer than directly converting a value into a desired output.

Regards,
Eduard

Posted 4-Dec-11 20:05pm

Eduard Lu

Comments

sathiyak 5-Dec-11 2:10am

Error 1 No overload for method 'TryParse' takes '1' arguments..........it comes

[no name] 5-Dec-11 2:13am

Of course you need to overload that method

int qty;
Int32.TryParse(row.FindControl("quantity", out qty);