Excel workbook, folder and picture files not closing/ending completely

Question

This project I am working on below is a reference card that pulls text from an excel file and pictures from the same searched folder. The process is then \"looped\" by calli

Answer 1

Workink with COM in .Net requires to release com objects. More than that, you cannot use dots when working with excel interop (or any other COM object) in .Net since between the dots, temporarly objects are created behind the scene and need to be released. For example, you wrote:

appXL.Workbooks.Open

You need to split it to

Dim workbooks as Excel.Workbooks
workbooks = appXL.WorkBooks
workbooks.Open
...
When time to release, you need to call Marhsal.ReleaseComObject(workbooks).

You must do it for all the excel objects you have in the code. An example of the usage of excel in VB.Net:

Public Function PrintExcel(sPath As String, iFrom As Integer) As String Implements IPrint.PrintExcel
    Dim xlApp As Excel.Application = Nothing
    Dim xlWorkBooks As Excel.Workbooks = Nothing
    Dim xlWorkBook As Excel.Workbook = Nothing
    Dim xlWorkSheets As Excel.Sheets = Nothing
    Dim xlWorkSheet As Excel.Worksheet = Nothing

    Try
        xlApp = New Excel.Application
        xlWorkBooks = xlApp.Workbooks
        xlWorkBook = xlWorkBooks.Open(sPath)
        xlWorkSheets = xlWorkBook.Sheets
        xlWorkSheet = xlWorkSheets(1)

       ' DO SOMETHING

        xlWorkBook.Close()

        xlWorkBooks.Close()
        xlApp.Quit()

    Catch ex As Exception
    Finally
        releaseObject(xlWorkSheet)
        releaseObject(xlWorkSheets)
        releaseObject(xlWorkBook)
        releaseObject(xlWorkBooks)
        releaseObject(xlApp)


    End Try
    Return s
End Function

Private Sub releaseObject(ByVal obj As Object)
    Try
        If obj IsNot Nothing Then
            Marshal.ReleaseComObject(obj)
        End If

    Catch ex As Exception

    Finally
        obj = Nothing
    End Try
End Sub

' ----------------------

Following your code with the fix, not checked:

Option Explicit On
Imports System
Imports System.IO
Imports System.Text
Imports Excel = Microsoft.Office.Interop.Excel

Public Class Form1
  Dim appXL As Excel.Application
  Dim wbXls As Excel.Workbooks
  Dim wbXl As Excel.Workbook
  Dim shXLs As Excel.Sheets    ' FIX 1: Sheets instead of WorkSheets
  Dim shXL As Excel.Worksheet
  Dim FldPath As String
  Dim PartID As String
  Dim RefCard As String
  Dim timeUpDate As Double

Private Sub Form1_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    'Dispaly Brembo Logo
    picLogo.SizeMode = PictureBoxSizeMode.StretchImage
    ReferenceCardDataPull()
End Sub

Private Sub Wait()
    Threading.Thread.Sleep(600000)
End Sub
Private Async Sub ReferenceCardDataPull()

    'Read File Source with part number ******************
    PartID = ("19.N111.10")

    ' Start Excel and get Application object.
    appXL = CreateObject("Excel.Application")
    appXL.Visible = False

    'Open Reference Card*************************************************************************************
    FldPath = ("\\HOMESHARE01\Public\Kaizens\Kaizen 44 - Missing Parts\Reference Cards\Completed Reference Cards by Part Number" & "\" & PartID)
    If System.IO.Directory.Exists(FldPath) Then
        wbXls = appXL.Workbooks
        wbXl = wbXls.Open(FldPath & "\" & PartID & ".xlsm")
        shXLs = wbXl.Worksheets
        shXL = shXLs("Sheet1")

        ' Copys Reference Card Data by Cell To App labels
        lblCODE.Text = shXL.Cells(6, 5).Value
        lblREV.Text = shXL.Cells(3, 5).Value
        lblDate.Text = shXL.Cells(9, 5).Value
        lblCustomer.Text = shXL.Cells(3, 1).Value
        lblPart.Text = shXL.Cells(6, 1).Value
        lblSpindleType.Text = shXL.Cells(9, 1).Value
        lblPaintType.Text = shXL.Cells(12, 1).Value
        lblDunnageType.Text = shXL.Cells(15, 1).Value
        lblPartsLayer.Text = shXL.Cells(3, 3).Value
        lblLayers.Text = shXL.Cells(6, 3).Value
        lblTotalParts.Text = shXL.Cells(9, 3).Value
        lblPackagingInstructs.Text = shXL.Cells(12, 3).Value

        'Pulls pictures from designated part folder
        If System.IO.File.Exists(FldPath & "\" & "PicSpindle" & PartID & ".JPG") Then
            picSpindle.Image = Image.FromFile(FldPath & "\" & "PicSpindle" & PartID & ".JPG")
            picSpindle.SizeMode = PictureBoxSizeMode.StretchImage
        Else
            picSpindle.SizeMode = PictureBoxSizeMode.StretchImage
        End If

        If System.IO.File.Exists(FldPath & "\" & "PicRotorTop" & PartID & ".JPG") Then
            picRotorTop.Image = Image.FromFile(FldPath & "\" & "PicRotorTop" & PartID & ".JPG")
            picRotorTop.SizeMode = PictureBoxSizeMode.StretchImage
        Else
            picRotorTop.SizeMode = PictureBoxSizeMode.StretchImage
        End If

        If System.IO.File.Exists(FldPath & "\" & "PicRotorBottom" & PartID & ".JPG") Then
            picRotorBottom.Image = Image.FromFile(FldPath & "\" & "PicRotorBottom" & PartID & ".JPG")
            picRotorBottom.SizeMode = PictureBoxSizeMode.StretchImage
        Else
            picRotorBottom.SizeMode = PictureBoxSizeMode.StretchImage
        End If

        If System.IO.File.Exists(FldPath & "\" & "PicDunnageFinal" & PartID & ".JPG") Then
            picDunnageFinal.Image = Image.FromFile(FldPath & "\" & "PicDunnageFinal" & PartID & ".JPG")
            picDunnageFinal.SizeMode = PictureBoxSizeMode.StretchImage
        Else
            picDunnageFinal.SizeMode = PictureBoxSizeMode.StretchImage
        End If

        If System.IO.File.Exists(FldPath & "\" & "PicDunnageLayer" & PartID & ".JPG") Then
            picDunnageLayer.Image = Image.FromFile(FldPath & "\" & "PicDunnageLayer" & PartID & ".JPG")
            picDunnageLayer.SizeMode = PictureBoxSizeMode.StretchImage
        Else
            picDunnageLayer.SizeMode = PictureBoxSizeMode.StretchImage
        End If

        ' Close objects
                          ' FIX 2: remove shXL = Nothing
        wbXl.Close()
        wbXls.Close()
        appXL.Quit()
                          ' FIX 3: remove appXL = Nothing           
        releaseObject(shXL)
        releaseObject(shXLs)
        releaseObject(wbXl)
        releaseObject(wbXls)
        releaseObject(appXL)


    Else
        lblCODE.Text = ("Error")
        lblCODE.ForeColor = Color.Red
        lblREV.Text = ("Error")
        lblREV.ForeColor = Color.Red
        lblDate.Text = ("Error")
        lblDate.ForeColor = Color.Red
        lblCustomer.Text = ("Error")
        lblCustomer.ForeColor = Color.Red
        lblPart.Text = ("Error")
        lblPart.ForeColor = Color.Red
        lblSpindleType.Text = ("Error")
        lblSpindleType.ForeColor = Color.Red
        lblPaintType.Text = ("Error")
        lblPaintType.ForeColor = Color.Red
        lblDunnageType.Text = ("Error")
        lblDunnageType.ForeColor = Color.Red
        Lable49.Text = ("Error")
        Lable49.ForeColor = Color.Red
        lblLayers.Text = ("Error")
        lblLayers.ForeColor = Color.Red
        lblTotalParts.Text = ("Error")
        lblTotalParts.ForeColor = Color.Red
        lblPackagingInstructs.Text = ("Error")
        lblPackagingInstructs.ForeColor = Color.Red
        lblError.Visible = True
    End If
    timeUpDate = 599
    tmrUpdate.Start()
    Application.DoEvents()

    Await Task.Run(Sub()
                       Wait()
                   End Sub)
    ReferenceCardDataPull()
End Sub

Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles tmrUpdate.Tick
    Dim hms = TimeSpan.FromSeconds(timeUpDate)
    Dim m = hms.Minutes.ToString
    Dim s = hms.Seconds.ToString

    If timeUpDate > 0 Then
        timeUpDate -= 1
        lblTimer.Text = (m & ":" & s)

    Else

        tmrUpdate.Stop()
        lblTimer.Text = "Updating"

    End If

End Sub

Private Sub releaseObject(ByVal obj As Object)
        Try
            If obj IsNot Nothing Then
                Marshal.ReleaseComObject(obj)
            End If

        Catch ex As Exception

        Finally
            obj = Nothing
        End Try
    End Sub

End Class