Re: why it always reads from second record?

[Phil Weber]

> Why the following loop always reads from the
> second record?

Holly: The .Read method reads the next record; you're calling it twice:

' Reads first record
If db.dbReader.Read() = True Then
' Reads second record
Do While db.dbReader.Read

Simply eliminate the outer If...Then, and you'll see all the records.
--
Phil Weber

[holly]

Thanks, Phil. But i want to use 'If...then' to check whether there are any
records before i do loop.
Holly

"Phil Weber" <philweber@hotmail.com> wrote:
> > Why the following loop always reads from the
> > second record?
>
>Holly: The .Read method reads the next record; you're calling it twice:
>
> ' Reads first record
> If db.dbReader.Read() = True Then
> ' Reads second record
> Do While db.dbReader.Read
>
>Simply eliminate the outer If...Then, and you'll see all the records.
>--
>Phil Weber
>

[Phil Weber]

> Thanks, Phil. But I want to use 'If...Then' to check
> whether there are any records before I do loop.

Holly: Why? The loop won't do anything if there are no records.

There's no way in .NET 1.0 to check whether a DataReader contains data
(version 1.1 adds a .HasRows method), and a DataReader is forward-only, so
there's no way to reset the record pointer to the beginning of the
DataReader after you've started reading.

You could use a DataSet instead of a DataReader; that would allow you to
determine the row count before your loop. Or you could do a separate query
(SELECT COUNT(*)...) to determine the number of rows that will be returned
before you actually query for the data.
--
Phil Weber

[holly]

Thanks,Phil