Problem using Excel with VB.Net

[Asgorath]

I use the following code samples on my app and it works perfectly.

Put this on the top of class/form declaration

Option Explicit On 
Option Strict On

To open a existing workbook:

Dim objExcel As new Excel.Application
        Dim Books As Excel.Workbooks
        Dim Book As Excel.Workbook
        Dim Sheet As Excel.Worksheet
 
 
        objExcel.Visible = True
        Books = objExcel.Workbooks
        '' open  the book
        Book = Books.Open(FileName)
        Sheet = DirectCast(Book.Worksheets(1), Excel.Worksheet)
 
 
        DirectCast(Book.Sheets("Sheet1"), Excel.Worksheet).Activate()
        Sheet = DirectCast(Book.ActiveSheet, Excel.Worksheet)

To create a new workbook :

Dim objApp As New Excel.Application
        Dim objBook As Excel.Workbook = objApp.Workbooks.Add
        Dim objSheet As Excel.Worksheet = DirectCast(objApp.ActiveSheet, Excel.Worksheet)
 
    objSheet.Range("A1).Value = "Hello"
    messagebox.show(objSheet.Range("A1").Text.ToString)
 
    objBook.SaveAs(FileName)
 
    objBook.Close
    objApp.Quit
    
    System.Runtime.InteropServices.Marshal.ReleaseComObject(objApp)

Regards
Jorge