}
protected void Button1_Click(object sender, EventArgs e)
{
int i=0;
CheckBox cb = new CheckBox();
for (i = 0; i < GridView1.Rows.Count; i++)
{
cb = (CheckBox)GridView1.Rows[i].Cells[0].FindControl("CheckBox1");
if (cb.Checked == true)
{
cai += cb.Text;