Re: Plug-in based development… - C# Discussion Boards

18-Apr-06 21:03

Hi,

I'm writing an application in c#.net and i'm completely new to it.
Please refer to the following code in which i'm getting an exception...

//.....................................................................

String classStartTime;

conn.Open();

String myQuery = "Select starttime from tblecture";

OdbcCommand myCommand = new System.Data.Odbc.OdbcCommand(myQuery, conn);

OdbcDataReader dataReader = myCommand.ExecuteReader();

try
{
while (dataReader.Read()) //exception
classStartTime = dataReader.GetTime(0).ToString();
}

finally
{
dataReader.Close();
conn.Close();
}

//.....................................................................

I'm getting this exception for only column named "starttime"; for other fields this code works fine.
Is there any other way to read a field of type time from database?

Thanks,
Kranti

-- modified at 4:13 Wednesday 19th April, 2006

Tehnoon18-Apr-06 22:09

Tehnoon

18-Apr-06 22:09

There is a very obvious mistake that you are making here. The query myQuery is returning you only one column per row. You are using dataReader.GetTime(1) , which is trying to get the second column (indexes are zero based, not 1 based) and hence generating an index out of range exception, because there is nothing at the "1" ordinal.

Solution:

Change the line
classStartTime = dataReader.GetTime(1).ToString();
to
classStartTime = dataReader.GetTime(0).ToString();

J4amieC18-Apr-06 22:11

18-Apr-06 22:11

In addition to the above, if your variable "classStartTime" is of type DateTime (as it should be) then you do not need the .ToString() call - it will cause an invalid cast exception.

if classStartTime is a string:
classStartTime = dataReader.GetString(0);

if classStartTime is DateTime:
classStartTime = dataReader.GetTime(0);

Guffa18-Apr-06 22:09

Guffa

18-Apr-06 22:09

The first field has index 0, not 1.

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Kranti125198418-Apr-06 22:18

18-Apr-06 22:18

even when i make it as ...

//...................................................

while (dataReader.Read()) //exception
classStartTime = dataReader.GetTime(0).ToString();

//...................................................

it generates the exception at the previous line i.e. the line containing "while", before going for this statement

Thanks,
Kranti

J4amieC18-Apr-06 23:06

18-Apr-06 23:06

What is the exception generated?

Kranti125198418-Apr-06 23:09

18-Apr-06 23:09

the exception generated is "Array index out of bounds"

J4amieC18-Apr-06 23:48

18-Apr-06 23:48

Array Index out of bounds was when you were trying to read element 1, that exception is unlikely to be being generated by the call to while(reader.Read()).

try posting the complete code, that is the relevant bit that is opening connection, creating command etc.

Kranti125198419-Apr-06 0:24

19-Apr-06 0:24

the complete code is as follows ...

//..................................

String connectionString = "Dsn=pgTEducation;database=teducation;server=192.168.0.135;port=5432;uid=divinet;readonly=0;protocol=6.4;fakeoidindex=0;showoidcolumn=0;rowversioning=0;showsystemtables=0;fetch=100;socket=4096;unknownsizes=0;maxvarcharsize=254;maxlongvarcharsize=8190;debug=0;commlog=0;optimizer=1;ksqo=1;usedeclarefetch=0;textaslongvarchar=1;unknownsaslongvarchar=0;boolsaschar=1;parse=0;cancelasfreestmt=0;extrasystableprefixes=dd_;lfconversion=1;updatablecursors=1;disallowpremature=0;trueisminus1=0;bi=0;byteaaslongvarbinary=0;useserversideprepare=0";

OdbcConnection conn = new System.Data.Odbc.OdbcConnection(connectionString);

String classStartTime;

conn.Open();

String myQuery = "Select starttime from tblecture";

OdbcCommand myCommand = new System.Data.Odbc.OdbcCommand(myQuery, conn);

OdbcDataReader dataReader = myCommand.ExecuteReader();

try
{
while (dataReader.Read())
classStartTime = dataReader.GetTime(0).ToString();
}
finally
{
dataReader.Close();
conn.Close();
}

//..................................

thanks,
Kranti

J4amieC19-Apr-06 0:40