DataSet Problem

[Sparky Arbuckle]

Error: There is no row at Position 0.

This is the line that errors:

If ds.Tables("DataTable").Rows(0)("Rev") Is Nothing Then strRev = "New"

In my strSQL I have: "SELECT TOP 1 ItemName, (IIf([Rev] Is Null, 'New',
'[Rev]')) As Rev ... "

I thought that I have covered all of my bases. Any suggestions on why
it is that I'm receiving an error?

 

[Jordan]

Your DataTable likely has zero rows.

Your code is attempting to look at the first row (row zero) - which doesn't
exist. The test for "Rev" being Nothing fails because there is no DataRow to
speak of, much less a column named "Rev" to evaluate for a possible value of
Nothing (or null). You are effectively telling your computer to "tell me if
a value is Nothing in a column in a row that doesn't exist." It's a
nonsensical question when you think about it.

You should add a test for Rows.Count... something like this:
If ds.Tables("DataTable").Rows.Count > 0 Then...

 

[Sparky Arbuckle]

When I run this SQL string in Access I always get at least 1 row
returned. This is due to my IIf function assigning '- ' if there is no
value in the first place. I added a rows count test to double-check
and make sure that my app didn't error out with 'There is no row at
Position 0.'
___________
Dim strSQL As String = "SELECT Max(IIf([Sheet.DCN] Is Null,'-
',[Sheet.DCN])) AS DCN, SheetType, SheetNumber FROM Sheet WHERE
(Sheet.Drawing = '" & x & "') AND (Sheet.SheetNumber = 0) GROUP BY
SheetNumber, SheetType;"


So the code below should assign strDCN a value of "- " if there are no
rows returned and if there is a row returned then strDCN equals the DCN
in that row.
___________
Dim strDCN As String

If ds.Tables("DataTable").Rows.Count < 0 Then
strDCN = "- "
Else
strDCN = ds.Tables("DataTable").Rows(0)("DCN")
End If

I am still getting "There is No Row at Position 0."