Work with Excel in VB.net fails without reason

Question

below code is about to export to excel file. Visual Studio sends the error in the picture. What is wrong with this code?

Imports Microsoft.Office.Interop.Excel
Module Module3
    Public Sub OOO()
        Dim excel As Application = New Application
        Dim workbook As Workbook = New Workbook
        Dim worksheet As Worksheet = workbook.ActiveSheet
        worksheet.Name = "Export as Excel Project"
        worksheet.Cells(1, 1) = "Value1"
        worksheet.Cells(2, 1) = "Value2"
        worksheet.SaveAs("d:\Actor.xls", Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookDefault)
        workbook.Close()
    End Sub
End Module

Answer 1

Your code is wrong starting by first Dim excel line. You expect that would be an Excel.Application but it is not, it is System.Windows.Application (as I understand from error window). If that line were correct, next line is trying to create an unrelated Workbook object. Instead try:

Sub Main
    Dim xl As Microsoft.Office.Interop.Excel.Application = New Microsoft.Office.Interop.Excel.Application()
    Dim workbook = xl.Workbooks.Add()
    Dim worksheet As Worksheet = CType(workbook.ActiveSheet, Worksheet)
    worksheet.Name = "Export as Excel Project"
    worksheet.Cells(1, 1) = "Value1"
    worksheet.Cells(2, 1) = "Value2"
    worksheet.SaveAs("d:\Actor.xlsx", Microsoft.Office.Interop.Excel.XlFileFormat.xlWorkbookDefault)
    workbook.Close()
    xl.Quit()
End Sub

Note that file extension is XLSX, not XLS for current versions of Excel (for a long time really, and Excel wouldn't open it without a warning if you happen to save as XLS).