how to get total of all column if GridView Paging is set as “True”? - asp.net

Question

this code display total of column in each page of grid view footer I want to display total of all columns in all pages footer
if (e.Row.RowType == DataControlRowType.DataRow)
{
string deb = ((Label)e.Row.FindControl("debit")).Text;
string cred = ((Label)e.Row.FindControl("credit")).Text;
decimal totalvalue = Convert.ToDecimal(deb) - Convert.ToDecimal(cred);
amount += totalvalue;
Label lbl = (Label)e.Row.FindControl("lblTotal");
lbl.Text = amount.ToString();
Label lblDebAmount = (Label)e.Row.FindControl("debit");
Label lblCredamount = (Label)e.Row.FindControl("credit");
float debtotal = (float)Decimal.Parse(lblDebAmount.Text);
float credtotal = (float)Decimal.Parse(lblCredamount.Text);
totalPriced += debtotal;
totalPricec += credtotal;
}
if (e.Row.RowType == DataControlRowType.Footer)
{
Label totallblCAmount = (Label)e.Row.FindControl("totallblDebAmount");
Label totallblCredAmount = (Label)e.Row.FindControl("totallblCredAmount");
totallblCAmount.Text = totalPriced.ToString("###,###.000");
totallblCredAmount.Text = totalPricec.ToString("###,###.000");
}
}

Answer 1

Why do it when the row is data bound? Why not do it when you originally bind the data?
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
DataTable dt = Database.GetData();
GridView1.DataSource = dt;
GridView1.DataBind();
//calculate here by manually adding up the debit/credit column from dt
//or do a separate database call that calculates the sum, ex: select sum(debits), sum(credits) from general_ledger
}
}
It makes sense to let the database do the math calculation for you. You wouldn't need to write your own custom calculation code. Just let the database's sum function handle it.
Here's a little more detail.
//Executes a SqlCommand and returns a DataTable
public class GetDataTable(SqlCommand command)
{
var dt = new DataTable();
using (var connection = new SqlConnection("connectionstring"))
{
command.Connection = connection;
connection.Open();
dt.Load(command.ExecuteReader());
}
return dt;
}
//Executes a SqlCommand and returns a scalar of type T
public static T GetScalar<T>(SqlCommand command)
{
using (var connection = new SqlConnection ("connectionstring"))
{
command.Connection = connection;
connection.Open();
var result = command.ExecuteScalar();
if (result is T)
{
return (T)result;
}
else
{
return (T)Convert.ChangeType(result, typeof(T));
}
}
}
//Load the data into the GridView, then get the credit amount and put the value in a label.
//You'll need to adjust the queries to match your schema
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
var tableCommand = new SqlCommand("select columns from table");
GridView1.DataSource = GetDataTable(tableCommand);
GridView1.DataBind();
var creditCommand = new SqlCommand("select sum(stat_amount) from tablename where stat_flag='c'");
var credits = GetScalar<decimal>(creditCommand);
Label1.Text = credits;
}
}