Unable to cast Object ..error while using VS2013 , MSOffice 2010 RRS feed

  • Question

  • Hello guys, sorry i am just a beginner when it comes to programming in VB.NET. i am developing a simple data management application for my personal use , part of the functions i want is to be able to export data to excel from the datagrid view. However whenever i run the particular event (by clickin the button) i always get this error

    " Unable to cast COM object of type 'Microsoft.Office.Interop.Excel.ApplicationClass' to class type 'Dstv.Microsoft.Office.Interop.Excel.Application'. Instances of types that represent COM components cannot be cast to types that do not represent COM components; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID of the interface."

    i have tried all i could but this error always come up on this line

    xlapp = excel.application

    below is the full code which i got from this platform and most peaople confirmed it to be working.

    Dim xlApp As Excel.Application
            Dim xlWorkBook As Excel.Workbook
            Dim xlWorkSheet As Excel.Worksheet
            Dim misValue As Object = System.Reflection.Missing.Value
            Dim i As Integer
            Dim j As Integer

            xlApp = New Excel.Application()
            xlWorkBook = xlApp.Workbooks.Add(misValue)
            xlWorkSheet = xlWorkBook.Sheets("Installation")

            For i = 0 To DataGridView2.RowCount - 2
                For j = 0 To DataGridView2.ColumnCount - 1
                    xlWorkSheet.Cells(i + 1, j + 1) = _
                        DataGridView2(j, i).Value.ToString()
            For j = 0 To DataGridView2.ColumnCount - 1
                xlWorkSheet.Cells(1, j + 1) = DataGridView2.Columns(j).Name
            For i = 0 To DataGridView2.RowCount - 1
                For j = 0 To DataGridView2.ColumnCount - 1
                    Dim cell As DataGridViewCell
                    cell = DataGridView2(j, i)
                    xlWorkSheet.Cells(i + 2, j + 1) = cell.Value

            Dim filename As String = "Installations -" & Now().ToString("yyyy-MM-dd-HH-mm-ss") & ".xlsx"
            xlWorkSheet.SaveAs(System.Environment.CurrentDirectory & filename)


            MsgBox("You can find the file in", System.Environment.CurrentDirectory & "installation.xls")
        End Sub

        Private Sub releaseObject(ByVal obj As Object)
                obj = Nothing
            Catch ex As Exception
                obj = Nothing
            End Try
        End Sub

    Any assistance will be highly appreciated. Funny enough most related error i have come accross is more of registory error but mine seems unique.

    Saturday, May 18, 2019 2:30 PM

All replies

  • As an update i already added reference microsoft excel 14.0 object library ....this is driving me crazy its been over a week that i have been struggling to make this work, i have uninstalled my office reinstalled several times without any luck. 

    Sorry  as a correction to my first post, the error always come up on 

    xlapp = new excel.application() 

    • Edited by DonBishop Saturday, May 18, 2019 2:34 PM
    Saturday, May 18, 2019 2:33 PM
  • If the error is on xlapp = new excel.application()  

    Try the following (which is only to test creating the application object)

    Option Strict On
    Option Infer On
    Imports Excel = Microsoft.Office.Interop.Excel
    Imports System.Runtime.InteropServices
    Module OpenWorkSheets2
        Public Sub OpenExcel1(ByVal FileName As String, ByVal SheetName As String)
            Dim xlApp As Excel.Application = Nothing
            Dim xlWorkBooks As Excel.Workbooks = Nothing
            Dim xlWorkBook As Excel.Workbook = Nothing
            Dim xlWorkSheet As Excel.Worksheet = Nothing
            Dim xlWorkSheets As Excel.Sheets = Nothing
            xlApp = New Excel.Application
            xlApp.DisplayAlerts = False
            xlWorkBooks = xlApp.Workbooks
            xlWorkBook = xlWorkBooks.Open(FileName)
            xlApp.Visible = True
            xlWorkSheets = xlWorkBook.Sheets
            For x As Integer = 1 To xlWorkSheets.Count
                xlWorkSheet = CType(xlWorkSheets(x), Excel.Worksheet)
                If xlWorkSheet.Name = SheetName Then
                    Console.WriteLine("Found sheet")
                    Exit For
                End If
                xlWorkSheet = Nothing
        End Sub
        Private Sub ReleaseComObject(ByVal obj As Object)
                If obj IsNot Nothing Then
                    obj = Nothing
                End If
            Catch ex As Exception
                obj = Nothing
            End Try
        End Sub
    End Module

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    Saturday, May 18, 2019 4:08 PM