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Problem OccurredCast from type ‘DBNull’ to type ‘String’ is not valid

I am working on optimizing an application which utilizes an access database. Just before the application finished processing I received and error message, Problem OccurredCast from type ‘DBNull’ to type ‘String’ is not valid. I’m not sure what is causing this, however I did some research and it appears to be related to null values in the database. How do fix this problem?
Thank you for taking the time to read this post,
Gr8life

appari

posted reply in your old question

gr8life

ASKER

I am trying the changed code now.
Thanks,
Gr8life

gr8life

ASKER

Still got the same error message when I ran the changed code against the 1,000 row data set.
Any suggestions?
Thanks,
Gr8life

bchoor

have you tried to check using IsDBNull(Value) ? If so, then you can prevent any interaction with that value.

Also, does it give you which field the error is happening on? Also, what exactly are you doing with the db, are you pulling the values in and peforming some operation on it - if so as I pointed out above, use the IsDBNull...like so

Let's say you have a datarow dr
Dim dr As DataRow = ds.Tables(0).rows(0)
Dim Field1Value As String = ""

If isdbNull(Dr.Item("Field1")) Then
Field1Value = ""
Else
Field1Value = Dr.Item("Field1")
End IF

HTH
~BC

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gr8life

ASKER

The change worked thank you very much,
Gr8life