creating excel worksheets using array

Question

I'm trying to create array of xlworksheets to be saved in xlsx format, and use the For Next structure. when I execute the program, the error points to xlWorkSheet(xlName).Name = "Judge " & xlName & " Score Summary" and the error message is "Object reference not set to an instance of an object."

I'm using vb.NET 2010

   Private Sub bgwSaveFiles_DoWork(ByVal sender As System.Object, ByVal e As System.ComponentModel.DoWorkEventArgs) Handles bgwSaveFiles.DoWork
    Dim xlApp As Excel.Application
    Dim xlWorkBook As Excel.Workbook
    ' Dim xlworksheet(), xlWorkSheetTotal As Object  Excel.Worksheet
    Dim misValue As Object = System.Reflection.Missing.Value
    Dim oRng As Excel.Range
    Dim R, C As Integer
    xlApp = New Excel.ApplicationClass
    xlWorkBook = xlApp.Workbooks.Add(misValue)
    Dim xlWorkSheet() As Excel.Worksheet
    Dim xlWorkSheetTotal As Excel.Worksheet
    For xli As Integer = 15 To 1
        xlworksheet(xli) = xlWorkBook.Worksheets.Add()
    Next
    xlWorkSheetTotal = xlWorkBook.Worksheets.Add()
    xlWorkBook.Worksheets("Sheet1").Delete()
    For xlName As Integer = 1 To 15
        xlWorkSheet(xlName).Name = "Judge " & xlName & " Score Summary"
    Next
    xlWorkSheetTotal.Name = "Final Score Summary"
    Dim Titles(9) As String
    Titles(0) = "Contestant Name"
    Titles(1) = "Portion"
    Titles(2) = "Contest Piece"
    Titles(3) = "Voice Quality"
    Titles(4) = "Musicality"
    Titles(5) = "Rhythm and Timing"
    Titles(6) = "Stage Performance"
    Titles(7) = "Total Score"

    '####### TOTAL SCORE SUMMARY #######
    For HT As Integer = 0 To 7
        xlWorkSheetTotal.Cells(1, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheetTotal.Cells(R + 2, C + 1) = SummaryScoreSheet.Rows.Item(R).Cells(C).Value
        Next
    Next
    xlWorkSheetTotal = xlWorkBook.Sheets("Final Score Summary")
    For HT As Integer = 0 To 7
        xlWorkSheetTotal.Cells(10, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheetTotal.Cells(R + 11, C + 1) = SummaryScoreSheet.Rows.Item(R + 7).Cells(C).Value
        Next
    Next

    oRng = xlWorkSheetTotal.Range("A1", "H1")
    oRng.EntireColumn.AutoFit()

    Dim judges() As Object
    judges(1) = "j1ScoreSheet"
    judges(2) = "j2ScoreSheet"
    judges(3) = "j3ScoreSheet"
    judges(4) = "j4ScoreSheet"
    judges(5) = "j5ScoreSheet"
    judges(6) = "j6ScoreSheet"
    judges(7) = "j7ScoreSheet"
    judges(8) = "j8ScoreSheet"
    judges(9) = "j9ScoreSheet"
    judges(10) = "j10ScoreSheet"
    judges(11) = "j11ScoreSheet"
    judges(12) = "j12ScoreSheet"
    judges(13) = "j13ScoreSheet"
    judges(14) = "j14ScoreSheet"
    judges(15) = "j15ScoreSheet"


    '####### START #######
    For HT As Integer = 0 To 7
        For jNo As Integer = 1 To 15
            xlworksheet(jNo).Cells(1, HT + 1) = Titles(HT)
        Next
    Next
    For R = 0 To 6
        For C = 0 To 7
            For jNo As Integer = 1 To 15
                xlworksheet(jNo).Cells(R + 2, C + 1) = judges(jNo).Rows.Item(R).Cells(C).Value
            Next
        Next
    Next
    For jNoLabel As Integer = 1 To 15
        xlworksheet(jNoLabel) = xlWorkBook.Sheets("Judge " & jNoLabel & " Score Summary")
    Next
    For HT As Integer = 0 To 7
        For jNo As Integer = 1 To 15
            xlworksheet(jNo).Cells(10, HT + 1) = Titles(HT)
        Next
    Next
    For R = 0 To 6
        For C = 0 To 7
            For jNo As Integer = 1 To 15
                xlworksheet(jNo).Cells(R + 11, C + 1) = judges(jNo).Rows.Item(R + 7).Cells(C).Value
            Next
        Next
    Next
    For jNo As Integer = 1 To 15
        oRng = xlworksheet(jNo).Range("A1", "H1")
    Next
    oRng.EntireColumn.AutoFit()


    With xlApp
        .DisplayAlerts = False
        On Error GoTo Err_Hndler
        Dim savePath As String = "C:\test\test.xlsx"
        For xli As Integer = 15 To 1
            xlworksheet(xli).SaveAs(savePath)
        Next
        xlWorkSheetTotal.SaveAs(savePath)
        .DisplayAlerts = True
    End With
    xlWorkBook.Close()
    xlApp.Quit()
    releaseObject(xlApp)
    releaseObject(xlWorkBook)
    releaseObject(xlWorkSheetTotal)
    MsgBox("Excel file created , you can find the file c:\")

Err_Hndler: MsgBox("Cannot create Excel record file. Please ensure the file is not open in other application", MsgBoxStyle.Exclamation + MsgBoxStyle.OkOnly, "Can't Create Record") Exit Sub End Sub''

actually, the program is working when I use this structure

        Dim xlApp As Excel.Application
    Dim xlWorkBook As Excel.Workbook
    Dim xlworksheets() As Excel.Worksheet
    Dim xlWorkSheetTotal, xlWorkSheet1, xlWorkSheet2, xlWorkSheet3, xlWorkSheet4, xlWorkSheet5, xlWorkSheet6, xlWorkSheet7, xlWorkSheet8, xlWorkSheet9, xlWorkSheet10, xlWorkSheet11, xlWorkSheet12, xlWorkSheet13, xlWorkSheet14, xlWorkSheet15 As Excel.Worksheet
    Dim misValue As Object = System.Reflection.Missing.Value
    Dim oRng As Excel.Range
    Dim R, C As Integer
    xlApp = New Excel.ApplicationClass
    xlWorkBook = xlApp.Workbooks.Add(misValue)
    xlWorkSheet15 = xlWorkBook.Worksheets.Add()
    xlWorkSheet14 = xlWorkBook.Worksheets.Add()
    xlWorkSheet13 = xlWorkBook.Worksheets.Add()
    xlWorkSheet12 = xlWorkBook.Worksheets.Add()
    xlWorkSheet11 = xlWorkBook.Worksheets.Add()
    xlWorkSheet10 = xlWorkBook.Worksheets.Add()
    xlWorkSheet9 = xlWorkBook.Worksheets.Add()
    xlWorkSheet8 = xlWorkBook.Worksheets.Add()
    xlWorkSheet7 = xlWorkBook.Worksheets.Add()
    xlWorkSheet6 = xlWorkBook.Worksheets.Add()
    xlWorkSheet5 = xlWorkBook.Worksheets.Add()
    xlWorkSheet4 = xlWorkBook.Worksheets.Add()
    xlWorkSheet3 = xlWorkBook.Worksheets.Add()
    xlWorkSheet2 = xlWorkBook.Worksheets.Add()
    xlWorkSheet1 = xlWorkBook.Worksheets.Add()
    xlWorkSheetTotal = xlWorkBook.Worksheets.Add()
    xlWorkBook.Worksheets("Sheet1").Delete()
    xlWorkSheet1.Name = "Judge 1 Score Summary"
    xlWorkSheet2.Name = "Judge 2 Score Summary"
    xlWorkSheet3.Name = "Judge 3 Score Summary"
    xlWorkSheet4.Name = "Judge 4 Score Summary"
    xlWorkSheet5.Name = "Judge 5 Score Summary"
    xlWorkSheet6.Name = "Judge 6 Score Summary"
    xlWorkSheet7.Name = "Judge 7 Score Summary"
    xlWorkSheet8.Name = "Judge 8 Score Summary"
    xlWorkSheet9.Name = "Judge 9 Score Summary"
    xlWorkSheet10.Name = "Judge 10 Score Summary"
    xlWorkSheet11.Name = "Judge 11 Score Summary"
    xlWorkSheet12.Name = "Judge 12 Score Summary"
    xlWorkSheet13.Name = "Judge 13 Score Summary"
    xlWorkSheet14.Name = "Judge 14 Score Summary"
    xlWorkSheet15.Name = "Judge 15 Score Summary"
    xlWorkSheetTotal.Name = "Final Score Summary"
    'xlWorkSheetTotal = xlWorkBook.Sheets("Final Score Summary")
    'xlWorkSheet1 = xlWorkBook.Sheets("Judge 1 Score Summary")
    Dim Titles(9) As String
    Titles(0) = "Contestant Name"
    Titles(1) = "Portion"
    Titles(2) = "Contest Piece"
    Titles(3) = "Voice Quality"
    Titles(4) = "Musicality"
    Titles(5) = "Rhythm and Timing"
    Titles(6) = "Stage Performance"
    Titles(7) = "Total Score"

    '####### TOTAL SCORE SUMMARY #######
    For HT As Integer = 0 To 7
        xlWorkSheetTotal.Cells(1, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheetTotal.Cells(R + 2, C + 1) = SummaryScoreSheet.Rows.Item(R).Cells(C).Value
        Next
    Next
    xlWorkSheetTotal = xlWorkBook.Sheets("Final Score Summary")
    For HT As Integer = 0 To 7
        xlWorkSheetTotal.Cells(10, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheetTotal.Cells(R + 11, C + 1) = SummaryScoreSheet.Rows.Item(R + 7).Cells(C).Value
        Next
    Next

    oRng = xlWorkSheetTotal.Range("A1", "H1")
    oRng.EntireColumn.AutoFit()


    '####### JUDGE 1 #######
    For HT As Integer = 0 To 7
        xlWorkSheet1.Cells(1, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheet1.Cells(R + 2, C + 1) = j1ScoreSheet.Rows.Item(R).Cells(C).Value
        Next
    Next
    xlWorkSheet1 = xlWorkBook.Sheets("Judge 1 Score Summary")
    For HT As Integer = 0 To 7
        xlWorkSheet1.Cells(10, HT + 1) = Titles(HT)
    Next
    For R = 0 To 6
        For C = 0 To 7
            xlWorkSheet1.Cells(R + 11, C + 1) = j1ScoreSheet.Rows.Item(R + 7).Cells(C).Value
        Next
    Next

    oRng = xlWorkSheet1.Range("A1", "H1")
    oRng.EntireColumn.AutoFit()

what I'm trying to accomplish here is can I shorten the code using For Next structure? it's too frustrating to type every code for every judge.

thank you!

Answer 1

Try replacing this:

Dim xlWorkSheet() As Excel.Worksheet
For xli As Integer = 15 To 1
    xlworksheet(xli) = xlWorkBook.Worksheets.Add()
Next

For xlName As Integer = 1 To 15
    xlWorkSheet(xlName).Name = "Judge " & xlName & " Score Summary"
Next

with this:

Dim xlWorkSheet As Excel.Worksheet
With xlWorkBook
    For xli As Integer = 1 To 15
        set xlWorkSheet = .Worksheets.Add(After:=.Worksheets(.Worksheets.Count))
        xlWorkSheet.Name = "Judge " & xli & " Score Summary"
    Next
End With