DataReader - Invalid attempt to read data when reader is closed.

[Patrick Olurotimi Ige]

With the code below i get error:-
Invalid attempt to read data when reader is closed.

//Get a datareader
SqlDataReader objDataReader;

objDataReader =
objCommand.ExecuteReader(CommandBehavior.CloseConn ection);

datalistoutput.DataSource = objDataReader;
datalistoutput.DataBind();

if (objDataReader["Sub_Category_Text"].ToString() == "asdas")
{
datalistoutput.Visible = true;
}
else
{
datalistoutput.Visible = false;
}

And if i want to check if "Sub_Category_Text" is NULL how can i do it
using my objDataReader?

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[Karl Seguin]

You can't...when you bind a DataReader to the DataSource of a control, you
read through the entire datareader and thus can't go back. You need to
either return it as a 2nd result and use objDataReader.nextResult or use a
dataset...

Karl

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"Patrick Olurotimi Ige" <ig*@iprimus.com.au> wrote in message
news:Os**************@TK2MSFTNGP10.phx.gbl...

With the code below i get error:-
Invalid attempt to read data when reader is closed.

//Get a datareader
SqlDataReader objDataReader;

objDataReader =
objCommand.ExecuteReader(CommandBehavior.CloseConn ection);

datalistoutput.DataSource = objDataReader;
datalistoutput.DataBind();

if (objDataReader["Sub_Category_Text"].ToString() == "asdas")
{
datalistoutput.Visible = true;
}
else
{
datalistoutput.Visible = false;
}

And if i want to check if "Sub_Category_Text" is NULL how can i do it
using my objDataReader?

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[Patrick Olurotimi Ige]

Thx Karl i ended up not using DataBind which worked as u adviced!
Is DataReader really faster then DataSet?
Cos i can't really see much difference btw them!


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[Karl Seguin]

It's situational. If you have many rows or many users than you'll start to
see a difference. The difference between using a DataSet or DataReader for
100 rows probably can't be measured by human perception. But make it 1000
rows with 100 users at the same time and you might start to feel the
difference :)

On the flip side, you can cache the DataSet...which will likely make it
faster (situational again), but will use up some memory (that's what memory
is there for, so do it, just don't eat up too much!)

Karl

--
MY ASP.Net tutorials
http://www.openmymind.net/ - New and Improved (yes, the popup is annoying)
http://www.openmymind.net/faq.aspx - unofficial newsgroup FAQ (more to
come!)
"Patrick Olurotimi Ige" <ig*@iprimus.com.au> wrote in message
news:%2***************@TK2MSFTNGP12.phx.gbl...

Thx Karl i ended up not using DataBind which worked as u adviced!
Is DataReader really faster then DataSet?
Cos i can't really see much difference btw them!


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Don't just participate in USENET...get rewarded for it!