System.NullReferenceException: Object reference not set to an instance of an object.

[aknamit]

I am getting error after publishing a website. At debug mode it works fine.
Any body can help me that what is the reason.

Private Sub fill_ddl_Dist(ByVal _query As String)
Dim con As Connection
con = New Connection
Dim ds As DataSet = con.GetRecord(_query)
' ddl_Dist.Items.Clear()
ddl_Dist.Items.Add("All")
'For Each row As DataRow In ds.Tables(0).Rows
' ddl.Items.Add(row(0).ToString)
'Next
For i As Integer = 0 To ds.Tables(0).Rows.Count - 1
ddl_Dist.Items.Add(ds.Tables(0).Rows(i).Item(0).To String)
Next
End Sub

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and error comes when i add or cleare item of DropDownList(dd l_dist.) if i remove these lines then error comes on dataset asignment line.

Please help me to understand the problem...

[tlhintoq]

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[Frinavale]

Well, according to the error it looks like your DataSet doesn't exist....
You should always check to make sure that Objects exist before you attempt to use them

For example, the following code will check to make sure that the DataSet "ds" exists before attempting to use it:

Dim ds As DataSet = con.GetRecord(_query)

If ds IsNot Nothing Then
  For Each row As DataRow In ds.Tables(0).Rows 
   ' .....
  Next
End If

The code that you have is not going to work though. As far as I know, you cannot fill a DataSet the way you are attempting to...

See:

• Using Database Connections without using wizards
• MSDN article on the topic

-Frinny

[aknamit]

thank you Frinny..
I've got solved that problem..You were right.
Thanks a lot..

[Frinavale]

I'm glad I could help!

Happy Coding!

-Frinny