my.Open();
            string ing = string.Format("insert into 点菜 values 菜名='{0}'  菜价='{1} and
             厨编号 ='{2}''", this.textBox1.Text, this.textBox2.Text,this.textBox3.Text);
            SqlCommand and = new SqlCommand(ing, my);
            SqlDataReader read = and.ExecuteNonQuery();  

 SqlDataReader read = and.ExecuteNonQuery();？
就这个转换出问题看看还有没有问题？