{"Fill: SelectCommand.Connection 属性尚未初始化。"}

主要代码：

返回dataset的函数：
public static DataSet dataset(string sqlstr)
        {
            DataSet ds = new DataSet();
            OleDbDataAdapter da = new OleDbDataAdapter();
            try
            {
                getconn();
                = CommandType.Text;
                = sqlstr;
                da.SelectCommand = comm;
                da.Fill(ds);
            }
            catch (Exception err)
            {
                throw new Exception(err.Message);
            }
            finally
            {
                closeconn();
            }
            return ds;
        }


调用函数的代码：
 try
            {
                string seltxt = "select * from users where username='"+uid+"'";
                DataSet dst = new DataSet();
                dst=dbaccess.dataset(seltxt);
                if (dst.Tables[0].Rows.Count <= 0)
                {
                    Response.Write("<script>alert(\"用户名不存在！\");</script>");
                    return;
                }
            }
            catch (Exception err)
            {
                throw new Exception(err.Message);
            }

然后就异常了，提示：{"Fill: SelectCommand.Connection 属性尚未初始化。"}
getconn()单独测试过，没问题的


求助各位高手，谢谢