How to show the total in footer of the grid view

Hi 

Please how I can show the total price  as footer side of the grid view from the following code

 this.dataGridView1.ColumnHeadersHeightSizeMode = System.Windows.Forms.DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            this.dataGridView1.Columns.AddRange(new System.Windows.Forms.DataGridViewColumn[] {
            this.Column1});
            this.dataGridView1.Location = new System.Drawing.Point(-7, 144);
            this.dataGridView1.Name = "dataGridView1";
            this.dataGridView1.RowTemplate.Height = 24;
            this.dataGridView1.Size = new System.Drawing.Size(1185, 435);
            this.dataGridView1.TabIndex = 0;



            DateTime datefrom;
            DateTime dateto;
            long invno;
            datefrom = this.dtpDateFrom.Value.Date;
            dateto = this.dtpDateTo.Value.Date;
            invno = 0;
            if (txtInvoice.Text != null && txtInvoice.Text != "" )
            {
                 invno = Int64.Parse(txtInvoice.Text);
            }        
        

            kmInvoice objKmInvoice = new kmInvoice();
            DataTable t = new DataTable();
            t = objKmInvoice.InvoiceList(datefrom, dateto,invno);
            dataGridView1.DataSource = t;

Please advise me how to show the total value of the invoice in footer of the fgridview

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polachan