DataReader brings back No data for Rows/Columns

testsubject · December 29th, 2005, 07:50 AM

Your going to love me. Unfortunately this still does not work. (Although to be honest I really thought it would do). Here is the current code.

Code:

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

Dim strPatNum As String = Request.QueryString("PatNum")
cnBarwickPas.Open()
Dim cmdPatsNextKin As New Odbc.OdbcCommand("SELECT ASSETCOM.MASTER5.MSMROL, ASSETCOM.NEXTKIN.NKMROLL, ASSETCOM.NEXTKIN.NKTITLE, ASSETCOM.NEXTKIN.NKFOREN, ASSETCOM.NEXTKIN.NKSURNM, ASSETCOM.NEXTKIN.NKADDR1, ASSETCOM.NEXTKIN.NKADDR2, ASSETCOM.NEXTKIN.NKADDR3, ASSETCOM.NEXTKIN.NKADDR4, ASSETCOM.NEXTKIN.NKPOST7, ASSETCOM.NEXTKIN.NKPHONE, ASSETCOM.NEXTKIN.NKRELAT FROM ASSETCOM.MASTER5, ASSETCOM.NEXTKIN WHERE ASSETCOM.MASTER5.MSMROL = ASSETCOM.NEXTKIN.NKMROLL AND ASSETCOM.MASTER5.MSMROL =" & strPatNum, cnBarwickPas)
Dim drPatsNextKin As Odbc.OdbcDataReader
drPatsNextKin = cmdPatsNextKin.ExecuteReader()
lblTitleSts.Text = drPatsNextKin.GetString(drPatsNextKin.GetOrdinal("NKTITLE"))
lblTitleSts.DataBind()
drPatsNextKin.Close()
cnBarwickPas.Close()

End Sub

This error I receive is:

Code:

No data exists for the row/column. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidOperationException: No data exists for the row/column.

Source Error: 

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.  

Stack Trace: 


[InvalidOperationException: No data exists for the row/column.]
   System.Data.Odbc.OdbcDataReader.internalGetString(Int32 i) +425
   System.Data.Odbc.OdbcDataReader.GetString(Int32 i) +5
   DDHPAS.WebForm7.Page_Load(Object sender, EventArgs e) +170
   System.Web.UI.Control.OnLoad(EventArgs e) +67
   System.Web.UI.Control.LoadRecursive() +35
   System.Web.UI.Page.ProcessRequestMain() +731

So I thought i would double check in SQL that there is data regarding that PatNum and there is, I also double checked to make sure that strPatNum was receiving the value from the query string request and it is.

As soon as I it tries to process this line "lblTitleSts.Text = drPatsNextKin.GetString(drPatsNextKin.GetOrdinal(" NKTITLE"))" thats when it falls over.

I also tried it with the "rPatsNextKin = cmdPatsNextKin.ExecuteReader(CommandBehavior.Singl eRow)" as well.

Imar · December 29th, 2005, 08:05 AM

A few things you can try:

1. Write out the complete SQL statement before you execute the reader. Then paste it in the query designer of your database and see if it works.

2. Remove the WHERE clause from your SQL. Then you can see what happens when you get a result set.

3. Check for HasRows to see if the reader returned a row before you try to access its data.

BTW, there is no need to call DataBind() on the label. Setting its Text property directly is enough.

HtH,

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

Imar · December 29th, 2005, 08:07 AM

Oh, and make sure you use the check for DBNull.Value I showed you earlier. Maybe there is a record, but the column you're trying to access is empty (null).

Imar
---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

helenas · January 16th, 2006, 05:37 PM

Hi

I have the similiar problem.
I'm using datareader (let's call it dr) to retrieve data from MS-SQL
and also receive an "No data exists for the row/column" error
when using dr.IsDBNull(0) method???

1. I've checked that datareader object contains data (dr.HasRows is true)
2. Other methods like dr.GetString(0) or dr.GetDataType(0) works fine!!!
3. But... using dr.IsDBNull(0) raises an error!!!

What may be the reason?
This issue is CRITICAL for me.

HELP please,
Helena