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DataReader has rows but no Data?

Posted on 2006-06-22
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Last Modified: 2008-02-01
I'm using an MS access database to store data for a program but when I go and try to receive data from the database via the code snippet below. When it get's to reading the data (in the line with the "*No Data*" label the following exception is thrown "No data exists for the row/column." with a source of "System.Data"

How can that happen when the HasRows'  property checks to see if there is data there or not?

OleDbCommand cmd = new OleDbCommand("SELECT * FROM Country WHERE NationID ='"+name+"';", conn);
                OleDbDataReader data = cmd.ExecuteReader();
               
                if (data.HasRows)
                {
     
                    numAirforce.Value = data.GetDecimal(3); *No data*
                    .....
               }
               data.Close();
               conn.Close();
0
Comment
Question by:gilllyo
5 Comments
 
LVL 5

Expert Comment

by:t_itanium
ID: 16966496
is the cmd executing properly??? try to use break points and f11 to trace the code......

some times writing sql command in such way raise an error

correction..

'" + name + "' have a space before and after the +'s

cheers
0
 
LVL 6

Expert Comment

by:MuhammadAdil
ID: 16966523
Hi Dear,

I think there is no need of ; and
          "SELECT * FROM Country WHERE NationID ='"+name+"'"
if (data.HasRows)
                {
                   data.Read();
                    numAirforce.Value = data.GetDecimal(3); *No data* // is this column can convert to decimal
                    .....
               }

Regards

Adil
0
 
LVL 11

Expert Comment

by:Agarici
ID: 16966715
when calling data.getdecimal no conversion is made so the column must be of type decimal

try using getfloat or getdouble according to your data model

hth,
A.
0
 
LVL 7

Accepted Solution

by:
pradeepsudharsan earned 125 total points
ID: 16967331
Hi,
try like this
if (data.HasRows)
{
    while (data.Read())
     {
      numAirforce.Value = data.GetDecimal(3);
      }
}
else
{
   //do nothing
}

Convert the data.GetDecimal(3) value to  numAirforce's data type

regards
Pradeep
0
 

Author Comment

by:gilllyo
ID: 16968301
Thank you...
0

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