Create Array from column in dataset (Resolved)

I want to create an array from a column in a dataset. Basicaly I want to put all the Zipcodes from the ueZip field into an array. Is that possible? My goal is to use what I learned on this thread Question about Array with an array created from a dataset instead of a hardcoded one as I do there.

VB Code:

Dim strSelect2 As String = _
            "Select ueStore, ueAddress, ueCity, ueState, " & _
            "ueZip From queUncEdsZCodes " & _
            "Where Latitude <=" & HighLatitude & _
            "And Latitude >=" & LowLatitude & _
            "And Longitude <=" & HighLongitude & _
            "And Longitude >=" & LowLongitude
 
        Dim Cmd2 As New OleDbDataAdapter(strSelect2, conn)
        Dim ds As New DataSet
        Cmd2.Fill(ds, "ZipCodes")
 
        Return ds
End Function
 
......Snip.....
 
Dim myDS As DataSet = GetUE_ZipRadius(tbZip.Text, CInt(tbRadius.Text))
DataGrid1.DataSource = myDS
DataGrid1.DataMember = "ZipCodes"

VB Code:

With ds.Tables("queUncEdsZCodes")
            Dim zipCodes(.Rows.Count - 1) As String
            For i As Integer = 0 To .Rows.Count - 1
                zipCodes(i) = DirectCast(.Rows(i).Item("ueZip"), String)
            Next
            'or
            Dim zips As New ArrayList
            For Each d As Data.DataRow In .Rows
                zips.Add(d.Item("ueZip"))
            Next
        End With

Like this? I get this error: Object reference not set to an instance of an object. It highlights this line zipCodesA(i) = DirectCast(.Rows(i).Item("ueZip"), String)

VB Code:

Dim strStaticZip As String = tbZip.Text
 
        Dim myDS As DataSet = _
            GetUE_ZipRadius(tbZip.Text, _
            CInt(tbRadius.Text))
 
        DataGrid1.DataSource = myDS
        DataGrid1.DataMember = "ZipCodes"
 
        With myDS.Tables("ZipCodes")
            Dim zipCodesA(.Rows.Count - 1) As String
            For i As Integer = 0 To .Rows.Count - 1
                zipCodesA(i) = DirectCast(.Rows(i).Item("ueZip"), String)
                LookUpZipCode(strStaticZip, zipCodesA(i))
                ListBox1.Items.Add(Format(CalcDistance(), "F").ToString)
            Next
        End With

Is your 'GetUE_ZipRadius(tbZip.Text, CInt(tbRadius.Text))' function returning a valid dataset, that contains a table with the ueZip column?


As a test, you could comment out the line:

VB Code:

zipCodesA(i) = DirectCast(.Rows(i).Item("ueZip"), String)

and replace it with:

VB Code:

zipCodesA(i) = "12345" 'choose one of your valid zip codes

This will fill your array with this one value of course, but you will be able to see if the code runs.

Andy_P when I did as you suggest the error went away. I put together a quick form to show that the dataset is loading data into the datagrid and that there is a field called ueZip. Of course the distances are all the same because it is hardcoded.

http://www.liberty1st.org/images/screen99.JPG

I changed it back and I didn' think I made any other changes but now I am getting a different error. This is it,

http://www.liberty1st.org/images/screen98.JPG

Well to me that suggestes that the data contained in the ueZip field is of the Integer type, not String, and as such, DirectCast is complaining.

If that is the case, perhaps this might work:

VB Code:

With myDS.Tables("ZipCodes")
            Dim zipCodesA(.Rows.Count - 1) As String
            Dim intZip as Integer
            For i As Integer = 0 To .Rows.Count - 1
                intZip = DirectCast(.Rows(i).Item("ueZip"), Integer)
                zipCodesA(i) = intZip.ToString
                LookUpZipCode(strStaticZip, zipCodesA(i))
                ListBox1.Items.Add(Format(CalcDistance(), "F").ToString)
            Next
        End With

Thanks Andy P when I tried that the IDE gave me an Option Strict warning about String to Integer type conversions and suggested this, which works (I love VS 2005).

zipCodesA(i) = CStr(DirectCast(.Rows(i).Item("ueZip"), Integer))

Thanks again for pointing me in the right direction.

No prob. :thumb:

Could you mark the thread as resolved if all is ok. :)