better code to display total sum in footer for perticular column?

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C#

WinForms

hi am using windows forms in asp.net using c# language..

this is my code to display grid but i want to show total sum for Purchase ,sales and Profit column

private void ExpressMoney_Load(object sender, EventArgs e)
       {
           btnDelete.Enabled = false;
           btnUpdate.Enabled = false;

           con.Open();
           da = new SqlDataAdapter("select * from tblExpressMoney where emDelStatus='0'", con);
           SqlCommandBuilder builder = new SqlCommandBuilder(da);
           ds = new DataSet();
           da.Fill(ds, "tblExpressMoney");

           dataGridView1.DataSource = ds.Tables["tblExpressMoney"];

           dataGridView1.Columns["emID"].HeaderText = "ID";
           dataGridView1.Columns["emNameOfCustomer"].HeaderText = "Name";
           dataGridView1.Columns["emCustomerNo"].HeaderText = "Mobile";
           dataGridView1.Columns["emTransactionNo"].HeaderText = "Transaction No";
           dataGridView1.Columns["emAmtOfTransaction"].HeaderText = "Purchase";
           dataGridView1.Columns["emTransfererAmtPaid"].HeaderText = "Sale";
           dataGridView1.Columns["emAmountOfProfit"].HeaderText = "Profit";
           dataGridView1.Columns["emDate"].HeaderText = "Date";
       }

please suggest me how to display footer in grid and how to display total sum?
for example
File->New->Project->VisualC#->Windows Forms Application
thanks