Ad:

C# Discussion Thread
Marked Solved
Views: 1028

Jul 23rd, 2009

Error in reading DataReader

Expand Post »

Hi

I want to read the content in datareader.So I use below coding to do that
if (dataReader4.IsDBNull(0)){

}
but I run above coding it gave me an error meassage.The error Meassage is
"Invalid attempt to read when no data is present".

then I use below coding
dataReader4["Email"]==null
but It also gave me above error meassage.There is no record for that field,that only for one record,for othere records there are email address.

Thanks
Tank50

Similar Threads

Error occured during the file system check. in Linux Applications and Software
IDE #1 error on bootup (Toshiba laptop) in Storage
Error while reading hard disk mbr through absread() in C++
Error reading zip in PHP
Cannot Find Server or DNS Error in Viruses, Spyware and other Nasties

Tank50

Reputation Points: 12

Solved Threads: 1

Junior Poster

Offline

124 posts
since Aug 2008

Permalink

Jul 23rd, 2009

Re: Error in reading DataReader

You missed Read() method.

c# Syntax (Toggle Plain Text)
if (dataReader4.Read())
   var=dataReader4.IsDBNull(0);
}
if (dataReader4.Read())
   var=dataReader4.IsDBNull(0);
}

adatapost

Moderator

Reputation Points: 2136

Solved Threads: 1228

Posting Genius

Offline

6,527 posts
since Oct 2008

Permalink

Jul 23rd, 2009

Re: Error in reading DataReader

Hi,
Read example here. It will help you. You have to call dataReader4.Read() before reading it. If still problem persist please post code what you have done so far.

DangerDev

Reputation Points: 165

Solved Threads: 59

Posting Pro in Training

Offline

485 posts
since Jan 2008

Permalink

Jul 23rd, 2009

Re: Error in reading DataReader

Click to Expand / Collapse Quote originally posted by Tank50 ...

Hi

I want to read the content in datareader.So I use below coding to do that
if (dataReader4.IsDBNull(0)){

}
but I run above coding it gave me an error meassage.The error Meassage is
"Invalid attempt to read when no data is present".

then I use below coding
dataReader4["Email"]==null
but It also gave me above error meassage.There is no record for that field,that only for one record,for othere records there are email address.

Thanks
Tank50

//****************************************************
Hi,
try this code to read datareader...

// Instance a new object
Object a = new Object();

// Check if datareader is null
if (datareader == null)
return;

// Get data from datareader
while (datareader.Read())
{
// Code example...
a = datareader.GetValue(0);
}

Hope it works for you...

See ya!!!

maestridaniele

Reputation Points: 10

Solved Threads: 1

Newbie Poster

Offline

1 posts
since Jul 2008

Permalink

Jul 23rd, 2009

Re: Error in reading DataReader

It looks like you start using the reader without reading some data first.

c# Syntax (Toggle Plain Text)
void ReadData(SqlConnection conn, string sql)
SqlDataReader datareader;
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = sql;
datareader = cmd.ExecuteReader();
while (datareader.Read()) {
 // perform your code here
}
}
void ReadData(SqlConnection conn, string sql)
SqlDataReader datareader;
SqlCommand cmd = new SqlCommand();
cmd.Connection = conn;
cmd.CommandText = sql;
datareader = cmd.ExecuteReader();
while (datareader.Read()) {
 // perform your code here
}
}

Cheers,
Dennis

djjaries

Reputation Points: 10

Solved Threads: 2

Newbie Poster

Offline

6 posts
since Mar 2008

Permalink

Jul 29th, 2009

Re: Error in reading DataReader

Hi

Thanks guys.I was in greate trouble coz of this error meassage.Now it ok ,I miss datareader.Read() part.

Tank50

Reputation Points: 12

Solved Threads: 1

Junior Poster

Offline

124 posts
since Aug 2008

This thread is solved

Either the thread starter or a moderator has marked this thread as solved. You can most likely trust the responses and answers given. There is most likely no reason for any further responses to be posted here. If you have a related question, please start a new thread in this forum instead.

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C# Forum Timeline: Access to member

Next Thread in C# Forum Timeline: calculator in c# !!!

DaniWeb Message

Cancel Changes

User Name
Password