How to check if a row exist in sql table using datagridview column?

Question

Hi

I am trying to check if a row exist in sql using a datagridview column

I am using these lines of code:

SqlCommand cmdcontrol= new SqlCommand("checkbarcode", conn);

cmdcontrol.CommandType = CommandType.StoredProcedure;

cmdcontrol.Parameters.AddWithValue("@barcode", Convert.ToString(tgproduct.Rows[i].Cells[0].Value));

int product = (int)cmdcontrol.ExecuteScalar();

if (product > 0)

{

//update qty of product based on barcode (from column index 0)

}

else

{

//do a insertion process with all details from datagridview

}

Note that the datagridview may have product that aren't inserted in sql , and products that are inserted in sql and need to update only QTY.

I tested the code to do insertion or update lonely (not both cases in same time) and code works, but when i mix both cases on of the processes isn't done(update or insert process).

I think the problem is in the loop code, where data from datagridview are checked to see if they exist in sql(and based on result the insertion/update process is done).

Could someone help me why when I put a product in datagridview which exist in sql( and need to update qty), and a procut that doesn't exist in sql table(need to insert the product), both process doesn't happen?

Thanks to everyone