Better way than this to export Datatable to Excel/Email?

this procedure will write your datatable to a specified excel file

Public Sub DataTableToExcel(ByVal fileName As String, ByVal dt As System.Data.DataTable)
	Dim ExlApp As Excel.Application
    	Dim aBook As Excel.Workbook
        Dim iCol, iRow, iColVal As Integer
        Dim missing As Object = System.Reflection.Missing.Value
        Dim i As Integer
        ' Open the document that was chosen by the dialog
        Dim aBook As Excel.Workbook
        Try
            ''re-initialize excel app
            ExlApp = New Excel.Application

            If ExlApp Is Nothing Then
                ''throw an exception
                Throw (New Exception("Unable to Start Microsoft Excel"))
            Else
                ''supresses overwrite warnings
                ExlApp.DisplayAlerts = False
               
                'aBook = New Excel.Workbook
                ''check if file exists
                If File.Exists(fileName) Then
                    aBook = ExlApp.Workbooks.Open(fileName)
                Else
                    aBook = ExlApp.Workbooks.Add(Excel.XlWBATemplate.xlWBATWorksheet)
                End If
                With ExlApp
                    .SheetsInNewWorkbook = 1
                    '.Workbooks.Add()
                    .Worksheets(1).Select()
                    'For displaying the column name in the the excel file.
                    For iCol = 0 To dt.Columns.Count - 1
                        ''clear column name before setting a new value
                        .Cells(1, iCol + 1).Value = ""
                        .Cells(1, iCol + 1).Value = dt.Columns(iCol).ColumnName.ToString
                    Next
                    'For displaying the column value row-by-row in the the excel file.
                    For iRow = 0 To dt.Rows.Count - 1
                        Try
                            For iColVal = 0 To dt.Columns.Count - 1
                                If TypeOf dt.Rows(iRow).ItemArray(iColVal) Is String Then
                                    .Cells(iRow + 2, iColVal + 1).Value = "'" & Trim(dt.Rows(iRow).ItemArray(iColVal).ToString)
                                Else
                                    .Cells(iRow + 2, iColVal + 1).Value = Trim(dt.Rows(iRow).ItemArray(iColVal).ToString)
                                End If
                            Next
                        Catch ex As Exception
                            err.WriteError("C:\ERRORS\", ex.Message, ex.StackTrace)
                            'err.WriteError(GetExecutingAssembly.Location.ToString() & "errorlog.txt", ex.Message, ex.StackTrace)
                            Console.Write("ERROR: " & ex.Message)
                        End Try
                    Next
                    If File.Exists(fileName) Then
                        .ActiveWorkbook().Save() 'fileName)
                    Else
                        .ActiveWorkbook().SaveAs(fileName, missing, missing, missing, missing, missing, Excel.XlSaveAsAccessMode.xlNoChange, missing, missing, missing, missing, missing)
                    End If
                    .ActiveWorkbook.Close()
                End With
                Console.Write("File exported sucessfully")
            End If
        Catch ex As Runtime.InteropServices.COMException
           
            Console.Write("ERROR: " & ex.Message)
        Catch ex As Exception
            
            Console.Write("ERROR: " & ex.Message)
        Finally
            ExlApp.Quit()
            System.Runtime.InteropServices.Marshal.ReleaseComObject(ExlApp)
            aBook = Nothing
            ExlApp = Nothing

        End Try
    End Sub

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Excel can connect directly to SQL Server and create a spreadsheet out of the result of a query.

You might be able to have Excel do all the job for your without having to go through a DataTable to retrieve the data.

Explore the Data...Import External Data menu entry in Excel 2003 or whatever ribbon entry that replaces that in newer versions.

Using that feature, your .NET code could simply open the Excel file, trigger a refresh of the data, save and the job is done. Simply send the result.

I have not worked with that feature in years, and used the scenario that I am suggesting from VB6 with old code I do not have anymore, so I cannot send you sample code. But I remember that it was very efficient and easy to code.

Thanks for your responses.  Please let me answer each in turn...

>> this procedure will write your datatable to a specified excel file

Yes that looks fine.  Some questions though:

1) I assume I need to create a Reference to Excel in the VB project for this to work?
2) Excel is not installed on the live server, only on development machines, so would this work in a live environment?
3) You appear to enumerate row-by-row, as in my example, so surely its not any more efficient?
4) Its also creating a file on the OS which I'm trying to avoid - can the file be passed straight from memory as an attachment?

>> Excel can connect directly to SQL Server and create a spreadsheet out of the result of a query.

That's a good idea, however, in this case Excel is being used as a third-party data transfer tool between two databases that cannot connect directly to one another.  Therefore the live machines won't have Excel, so .NET is doing the work of reading the data and converting to ADO.NET.

take a look at this

http://stackoverflow.com/questions/5621577/export-from-sql-server-to-excel-file-using-asp-net-and-vb-net

http://www.codeproject.com/Articles/164582/8-Solutions-to-Export-Data-to-Excel-for-ASP-NET

Hey YZlat

Thanks for the follow up.

>>> 3) You appear to enumerate row-by-row, as in my example, so surely its not any more efficient?
>>  Do you have other suggestions?

Nope, but, being new to this type of thing I wondered if there was any method I wasn't aware of to 'push' the DataTable into a text representation without enumeration being necessary.
I tried getting SQL to export the results as XML, which worked really well, however, Excel 2003 (on the client server) could not open it natively without Importing.

From the links you posted, the first is very similar to what I've done initially, which gives me reassurance that I've not wasted my time, so thanks for that.

The second link involves using a webcontrol, which I do within my web apps (where my skills lie), however, I was researching to see if there was a 'better Forms method' than this.  Anyway I'm kind of glad there isn't because at least now I can move on.

Thanks for your help and clarification.