STAThreadAttribute with SaveFileDialog VB.NET - vb.net

Question

I have an application to export ListView to Excel sheet , and im trying to do this in background but i have error in SaveFileDialog.showdialog().This is the error :
An exception of type 'System.Threading.ThreadStateException' occurred
in System.Windows.Forms.dll but was not handled in user code
Additional information: Current thread must be set to single thread apartment (STA) mode before OLE calls can be made. Ensure that your Main function has STAThreadAttribute marked on it. This exception is only raised if a debugger is attached to the process.
and this is my code :
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
BackgroundWorker1.RunWorkerAsync()
End Sub
Public Sub saveExcelFile(ByVal FileName As String)
Try
Dim xls As New Excel.Application
Dim sheet As Excel.Worksheet
Dim i As Integer
xls.Workbooks.Add()
sheet = xls.ActiveWorkbook.ActiveSheet
Dim row As Integer = 1
Dim col As Integer = 1
For i = 0 To Me.ListView1.Columns.Count - 1
sheet.Cells(1, i + 1) = Me.ListView1.Columns(i).Text
Next
For i = 0 To Me.ListView1.Items.Count - 1
For j = 0 To Me.ListView1.Items(i).SubItems.Count - 1
sheet.Cells(i + 2, j + 1) = Me.ListView1.Items(i).SubItems(j).Text
Next
Next
row += 1
col = 1
' for the header
sheet.Rows(1).Font.Name = "Cooper Black"
sheet.Rows(1).Font.size = 12
sheet.Rows(1).HorizontalAlignment = Excel.XlVAlign.xlVAlignCenter
Dim mycol As System.Drawing.Color = System.Drawing.ColorTranslator.FromHtml("#148cf7")
sheet.Rows(1).Font.color = mycol
' for all the sheet without header
sheet.Range("a2", "z1000").Font.Name = "Arial"
sheet.Range("a2", "z1000").Font.Size = 13
sheet.Range("a2", "z1000").HorizontalAlignment = Excel.XlVAlign.xlVAlignCenter
sheet.Range("A1:X1").EntireColumn.AutoFit()
sheet.Range("A1:X1").EntireRow.AutoFit()
xls.ActiveWorkbook.SaveAs(FileName)
xls.Workbooks.Close()
xls.Quit()
Catch ex As Exception
End Try
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
Try
Dim saveFileDialog1 As New SaveFileDialog
saveFileDialog1.Filter = "Excel File|*.xlsx"
saveFileDialog1.Title = "Save an Excel File"
saveFileDialog1.ShowDialog()
If saveFileDialog1.FileName <> "" Then
saveExcelFile(saveFileDialog1.FileName)
End If
Catch ex As Exception
End Try
End Sub
Private Sub BackgroundWorker1_RunWorkerCompleted(sender As Object, e As System.ComponentModel.RunWorkerCompletedEventArgs) Handles BackgroundWorker1.RunWorkerCompleted
MsgBox("done")
End Sub

Answer 1

You could move everything concerning SaveFileDialog1 to Button3_Click and store the filename in a Private variable, so it can be used later in BackgroundWorker1_DoWork.
Private _filename As String
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
SaveFileDialog1.Title = "Save Excel File"
SaveFileDialog1.Filter = "Excel files (*.xls)|*.xls|Excel Files (*.xlsx)|*.xslx"
SaveFileDialog1.ShowDialog()
'exit if no file selected
If SaveFileDialog1.FileName = "" Then
Exit Sub
End If
_filename = SaveFileDialog1.FileName
BackgroundWorker1.RunWorkerAsync()
End Sub
Private Sub BackgroundWorker1_DoWork(sender As Object, e As System.ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
...
book.SaveAs(_filename)
...
End Sub

Answer 2

i put this code in load form and everything is perfect:
Control.CheckForIllegalCrossThreadCalls = False