datagridview,想实现编辑数据的功能 指定的参数已超出有效值的范围。 参数名: index；”解决办法

 protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)    {        try        {            int index = e.RowIndex;//当前选择行索引值           string roomno = GridView1.DataKeys[index].Value.ToString();//获取主键房间号           string roomtype = ((TextBox)(GridView1.Rows[index].Cells[4].Controls[0])).Text.Trim();           string roomstatu = ((TextBox)(GridView1.Rows[index].Cells[5].Controls[0])).Text.Trim();           string unitprice = ((TextBox)(GridView1.Rows[index].Cells[6].Controls[0])).Text.Trim();           string sql = "update room set roomtype="+roomtype+",roomstatu="+roomstatu+",unitprice="+unitprice+"";//更新语句           SqlConnection conn = new SqlConnection(strCon);           conn.Open();           SqlCommand comm = new SqlCommand(sql, conn);           int ret = comm.ExecuteNonQuery();            if (ret>0)            {                //更新成功            }            else            {                //更新失败            }            GridView1.EditIndex = -1;            DataBind();        }        catch (Exception ex)        {         throw;        }    } protected void GridView1_RowDeleting(object sender, GridViewDeleteEventArgs e)    {        int index = e.RowIndex;        string roomno = GridView1.DataKeys[index].Value.ToString();        //rxxx ro = new rxxx();        //ro.roomno = roomno;        //ro.Del();        string sql = "delete from room where roomno="+roomno+"";//更新语句        SqlConnection conn = new SqlConnection(strCon);        conn.Open();        SqlCommand comm = new SqlCommand(sql, conn);        conn.Close();        DataBind();    }