foreach (GridViewRow gvr in GridView1.Rows)
        {
            TextBox t = (TextBox)gvr.Cells[0].Controls[0];
          //  Response.Write("<br />" + t.Text);
        }

 TemplateField tf = new TemplateField();
            tf.HeaderText = “NewTemplate column”;
            MyTemplate template = new MyTemplate(“test”);
            tf.ItemTemplate = template;
            GridView1.Columns.Clear();
            GridView1.Columns.Add(tf);
 
            string[] s = { “as”, “34″, “z”, “@#4″, “666″ };
            GridView1.DataSource = s;
            GridView1.DataBind();