运行这段代码为什么出现实时错误“32001”无效的HDC

CommonDialog1.Flags = cdlPDReturnDC + cdlPDNoPageNums
   If RichTextBox1.SelLength = 0 Then
      CommonDialog1.Flags = CommonDialog1.Flags + cdlPDAllPages
   Else
      CommonDialog1.Flags = CommonDialog1.Flags + cdlPDSelection
   End If
  CommonDialog1.ShowPrinter
  RichTextBox1.SelPrint CommonDialog1.hDC此代码实现用SelPrint 方法打印 RichTextBox 的内容功能