C# 如何将上载的.doc格式更改为.txt格式？

我正在使用C开发一个项目。为此，我想将.doc格式转换为.txt格式并将其发送到打印机。现在我使用以下代码。但它没有将word格式转换为txt格式。我怎么做

OpenFileDialog ofd = new OpenFileDialog();
                    DialogResult result = ofd.ShowDialog();
                    if (result == DialogResult.OK) // Test result.
                    {
                        fileName = ofd.FileName;

                        var application = new Microsoft.Office.Interop.Word.Application();
                        //read all text into content

                        try
                        {
                            System.Windows.Forms.RichTextBox rtBox = new System.Windows.Forms.RichTextBox();

                            //string rtfText = System.IO.File.ReadAllText(fileName);
                            //rtBox.Rtf = rtfText;
                            //string plainText = rtBox.Text;

                            content = System.IO.File.ReadAllText(fileName);
                        }
                        catch (Exception ex)
                        {
                            MessageBox.Show(ex.Message);
                            //Show handeled Exceptions
                        }




                   PrintDialog printDlg = new PrintDialog();
                    PrintDocument printDoc = new PrintDocument();
                    printDoc.DocumentName = "fileName";
                    printDlg.Document = printDoc;
                    printDlg.AllowSelection = true;
                    printDlg.AllowSomePages = true;
                    //Call ShowDialog
                    if (printDlg.ShowDialog() == DialogResult.OK)
                    {
                        printDoc.PrintPage += new PrintPageEventHandler(pd_PrintPage);
                        printDoc.Print();

                        Thread.Sleep(3000);
                        MessageBox.Show("Uploded file has sent to Printer");

                    }

private void pd_PrintPage(object sender, PrintPageEventArgs ev)
        {
            ev.Graphics.DrawString(content, new System.Drawing.Font(new FontFamily("Times new Roman"), 12f), Brushes.Black,
                            ev.MarginBounds.Left, 0, new StringFormat());
        }

您可以尝试以下方法：

application.Documents.Open(fileName);
application.ActiveDocument.SaveAs2(fileName, WdSaveFormat.wdFormatText);

这将把Word文档保存到文本文件中。请注意，您可能会丢失诸如Word对象之类的信息，但我想您已经知道了。

您是否尝试过，Path.ChangeExtensionfileName.txt；？