VB.NET - 句柄无效

Question

美好的一天， 我正在尝试使用PrintDocument打印文档

Using doc As New Printing.PrintDocument
      With doc
           .PrinterSettings = dlg.PrinterSettings
           AddHandler doc.PrintPage, AddressOf PrintToPage
           If .PrinterSettings.IsValid Then
              doc.Print()
           End If
       End With
End Using

在“.Print（）”之后，它会抛出“句柄无效”的错误。

System.Drawing
    at System.Drawing.Printing.StandardPrintController.OnStartPage(PrintDocument document, PrintPageEventArgs e) 
    at System.Windows.Forms.PrintControllerWithStatusDialog.OnStartPage(PrintDocument document, PrintPageEventArgs e)
    at System.Drawing.Printing.PrintController.PrintLoop(PrintDocument document)
    at System.Drawing.Printing.PrintController.Print(PrintDocument document)
    at System.Drawing.Printing.PrintDocument.Print()