How to avoid IndexOutOfRangeException indexing DataReader columns?

Question

I am having a little trouble with an 'IndexOutOfRangeException'. I think it is because when the code tries to get the DateModified col from the database it sometimes contains NULLS (the users haven't always updated the page since they created it).

Here is my code;

s = ("select datemodified, maintainedby, email, hitcount from updates where id =   @footid")
Dim x As New SqlCommand(s, c)
x.Parameters.Add("@footid", SqlDbType.Int)
x.Parameters("@footid").Value = footid
c.Open()
Dim r As SqlDataReader = x.ExecuteReader
While r.Read
    If r.HasRows Then
        datemodified = (r("DateModified"))
        maintainedby = (r("maintainedby"))
        email = (r("email"))
        hitcount = (r("hitcount"))
    End If
End While
c.Close()

I thought (after a bit of msdn) that adding;

If r.HasRows Then 

End If

Would solve the problem, but so far after adding I am still getting the same old IndexOutOfRangeException

(ps, I have tried datemodified as string / datetime)

I have tried; If r.Item("DateModified") IsNot DBNull.Value Then datemodified = (r("DateModified")) Else datemodified = String.Empty End If (but didnt seem to work) — Phil
– Phil, Commented Feb 9, 2010 at 8:30

John Saunders · Accepted Answer · 2010-02-17 03:47:28Z

1

Try r.IsDBNull(columnIndex).

answered Feb 17, 2010 at 3:47

John Saunders

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Aryabhatta · Accepted Answer · 2010-02-09 07:46:53Z

1

Does changing

datemodified = (r("DateModified"))

to

datemodified = (r("datemodified"))

work?

answered Feb 9, 2010 at 7:46

Aryabhatta

1 Comment

Phil Over a year ago

Thanks for the help, No i did have it as datemodified then I changed to DateModified as an attempt to fix the problem.

Bentley Davis · Accepted Answer · 2010-02-17 03:36:25Z

1

I have tried to recreate you issue by passing in nulls, empty sets. I can't recreate it in the sample of code you provided. Would you mind posting more code, maye even the whole page? Is there a line number that the error happens on? I would like to dig in further.

answered Feb 17, 2010 at 3:36

Bentley Davis

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