Object reference not set to an instance of an object.

im filling a datset with names of films and need to get the number of
films in the dataset. basically i want to know if its empty. but when
i try and get the number of rows it gives me the error: "Object
reference not set to an instance of an object" . I get this error from
the line:"Label3.Text =
CalendarFilmsDataSet11.Tables("Customers").Rows.Count". and i get the
error whether the dataset has items in it or not. can anyone tell me
why this is happening.
this is my code:
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles MyBase.Load
If Not Page.IsPostBack Then
Label2.Text = "Films Showing on " + Session("theShowDate")
CalendarFilmsDataSet11.Clear()
OdbcDataAdapter1.SelectCommand.Parameters("cinemaID").Value
= Session("theCinemaID")
OdbcDataAdapter1.SelectCommand.Parameters("showDate").Value
= Session("theShowDate")
OdbcDataAdapter1.Fill(CalendarFilmsDataSet11)
Label3.Text =
CalendarFilmsDataSet11.Tables("Customers").Rows.Count
ListBox1.DataBind()
End If
End Subthe correct way to access data in a dataset is to first test using if
statements
if(ds != null && ds.Tables != null && ds.Tables.Count > 0 etc
________________________
Warm regards,
Alvin Bruney [MVP ASP.NET]
[Shameless Author plug]
The O.W.C. Black Book with .NET
www.lulu.com/owc, Amazon
Professional VSTO.NET - Wrox/Wiley 2006
----
"bazzer" <somersbar@.yahoo.com> wrote in message
news:1144940392.384018.153860@.e56g2000cwe.googlegroups.com...
> im filling a datset with names of films and need to get the number of
> films in the dataset. basically i want to know if its empty. but when
> i try and get the number of rows it gives me the error: "Object
> reference not set to an instance of an object" . I get this error from
> the line:"Label3.Text =
> CalendarFilmsDataSet11.Tables("Customers").Rows.Count". and i get the
> error whether the dataset has items in it or not. can anyone tell me
> why this is happening.
> this is my code:
> Private Sub Page_Load(ByVal sender As System.Object, ByVal e As
> System.EventArgs) Handles MyBase.Load
> If Not Page.IsPostBack Then
> Label2.Text = "Films Showing on " + Session("theShowDate")
> CalendarFilmsDataSet11.Clear()
> OdbcDataAdapter1.SelectCommand.Parameters("cinemaID").Value
> = Session("theCinemaID")
> OdbcDataAdapter1.SelectCommand.Parameters("showDate").Value
> = Session("theShowDate")
> OdbcDataAdapter1.Fill(CalendarFilmsDataSet11)
> Label3.Text =
> CalendarFilmsDataSet11.Tables("Customers").Rows.Count
> ListBox1.DataBind()
> End If
> End Sub
>
On Thu, 13 Apr 2006 11:26:47 -0400, Alvin Bruney wrote:

> the correct way to access data in a dataset is to first test using if
> statements
> if(ds != null && ds.Tables != null && ds.Tables.Count > 0 etc
Or, in VB, as the original author seems to be using
If not ds is Nothing AndAlso not ds.Tables is Nothing AndAlso
ds.Tables.Count > 0 ...
right. 2.0 also gives VB the IsNot function as well
If ds IsNot Nothing
I'm not aware if there is a performance improvement though.
--
________________________
Warm regards,
Alvin Bruney [MVP ASP.NET]
[Shameless Author plug]
The O.W.C. Black Book with .NET
www.lulu.com/owc, Amazon
Professional VSTO.NET - Wrox/Wiley 2006
----
"Erik Funkenbusch" <erik@.despam-funkenbusch.com> wrote in message
news:1lsvaw55khggs.dlg@.funkenbusch.com...
> On Thu, 13 Apr 2006 11:26:47 -0400, Alvin Bruney wrote:
>
> Or, in VB, as the original author seems to be using
> If not ds is Nothing AndAlso not ds.Tables is Nothing AndAlso
> ds.Tables.Count > 0 ...