Null Exception - DataGridItem

[Adam Knight]

Hi all,

The following code works fine.

If i remove the try statement, i recieve a generic is null exception when
trying to retrieve a datagrids data item.

With the try those exceptions are obviously caught, but it is clear the data
item is accessible otherwise as i am able to use its value.

I am just wondering (without the try statement) what the function could be
encountering to set of the null exception error.

Any thoughts?

Adam

Sub dgAnswerOptions _ItemDataBound( ByVal sender As Object, ByVal e As
DataGridItemEve ntArgs)

'determine if current item is not a header or footer
If(e.Item.ItemT ype <> ListItemType.He ader Or e.Item.ItemType <>
ListItemType.Fo oter) Then

'add index to answer options
e.Item.Cells(0) .Controls.Add(N ew
LiteralControl( e.Item.ItemInde x + 1 & "."))

'determin if logged in user belongs to the director or admin
groups
If(Security.IsD irector() Or Security.IsAdmi n()) Then

Try

'determine if current option is a correct option
If(e.Item.DataI tem.Item(2) = 1) Then //error occurs
here without try

'change cell formatting to reflect a correct
answer
e.Item.Cells(1) .CssClass = "correct"
e.Item.Cells(1) .Text = e.Item.Cells(1) .Text & "
(Correct)"

End If

Catch

e.Item.Cells(1) .Controls.Add(N ew LiteralControl( "
Type: " & e.Item.ItemType ))

End Try

End If

End If

End Sub

[Mr Newbie]

Re: Null Exception - DataGridItem

The problem I think is that the data item may be null yet you are testing it
against nothing first





"Adam Knight" <adam@pertrain. com.au> wrote in message
news:e4S6kJ0vFH A.3588@tk2msftn gp13.phx.gbl...[color=blue]
> Hi all,
>
> The following code works fine.
>
> If i remove the try statement, i recieve a generic is null exception when
> trying to retrieve a datagrids data item.
>
> With the try those exceptions are obviously caught, but it is clear the
> data item is accessible otherwise as i am able to use its value.
>
> I am just wondering (without the try statement) what the function could be
> encountering to set of the null exception error.
>
> Any thoughts?
>
> Adam
>
> Sub dgAnswerOptions _ItemDataBound( ByVal sender As Object, ByVal e As
> DataGridItemEve ntArgs)
>
> 'determine if current item is not a header or footer
> If(e.Item.ItemT ype <> ListItemType.He ader Or e.Item.ItemType <>
> ListItemType.Fo oter) Then
>
> 'add index to answer options
> e.Item.Cells(0) .Controls.Add(N ew
> LiteralControl( e.Item.ItemInde x + 1 & "."))
>
> 'determin if logged in user belongs to the director or admin
> groups
> If(Security.IsD irector() Or Security.IsAdmi n()) Then
>
> Try
>
> 'determine if current option is a correct option
> If(e.Item.DataI tem.Item(2) = 1) Then //error occurs
> here without try
>
> 'change cell formatting to reflect a correct
> answer
> e.Item.Cells(1) .CssClass = "correct"
> e.Item.Cells(1) .Text = e.Item.Cells(1) .Text & "
> (Correct)"
>
> End If
>
> Catch
>
> e.Item.Cells(1) .Controls.Add(N ew LiteralControl( "
> Type: " & e.Item.ItemType ))
>
> End Try
>
> End If
>
> End If
>
> End Sub
>
>[/color]

[Elton W]

RE: Null Exception - DataGridItem

You might try condition

If e.Item.ItemType = ListItemType.It em Or e.Item.ItemType =
ListItemType.Al ternatingItem Then

If(e.Item.ItemT ype <> ListItemType.He ader Or e.Item.ItemType <>[color=blue]
> ListItemType.Fo oter)[/color]

might catch some other items

HTH

Elton Wang

"Adam Knight" wrote:
[color=blue]
> Hi all,
>
> The following code works fine.
>
> If i remove the try statement, i recieve a generic is null exception when
> trying to retrieve a datagrids data item.
>
> With the try those exceptions are obviously caught, but it is clear the data
> item is accessible otherwise as i am able to use its value.
>
> I am just wondering (without the try statement) what the function could be
> encountering to set of the null exception error.
>
> Any thoughts?
>
> Adam
>
> Sub dgAnswerOptions _ItemDataBound( ByVal sender As Object, ByVal e As
> DataGridItemEve ntArgs)
>
> 'determine if current item is not a header or footer
> If(e.Item.ItemT ype <> ListItemType.He ader Or e.Item.ItemType <>
> ListItemType.Fo oter) Then
>
> 'add index to answer options
> e.Item.Cells(0) .Controls.Add(N ew
> LiteralControl( e.Item.ItemInde x + 1 & "."))
>
> 'determin if logged in user belongs to the director or admin
> groups
> If(Security.IsD irector() Or Security.IsAdmi n()) Then
>
> Try
>
> 'determine if current option is a correct option
> If(e.Item.DataI tem.Item(2) = 1) Then //error occurs
> here without try
>
> 'change cell formatting to reflect a correct
> answer
> e.Item.Cells(1) .CssClass = "correct"
> e.Item.Cells(1) .Text = e.Item.Cells(1) .Text & "
> (Correct)"
>
> End If
>
> Catch
>
> e.Item.Cells(1) .Controls.Add(N ew LiteralControl( "
> Type: " & e.Item.ItemType ))
>
> End Try
>
> End If
>
> End If
>
> End Sub
>
>
>[/color]