主题：[求助]Word另存为rtf文件

老师好！

我利用代码更改Word文档的后缀为.rtf后，通过RichTextBox打开会出现乱码。打开rtf代码如下。

Dim ct As New System.Windows.Forms.RichTextBox

ct.Dock = System.Windows.Forms.DockStyle.Fill

ct.Name ="RichTextBox1"

e.Form.Controls("Panel1").BaseControl.Controls.Add(ct)

Dim f As Font = New Font("Verdana", 16F, FontStyle.Regular, GraphicsUnit.Point)

ct.Font = f

ct.LoadFile("d:\test.rtf",System.Windows.Forms.RichTextBoxStreamType.PlainText)

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打开Word后另存为rtf文件，没有出现乱码问题。因此请教怎样把Word文件另存为rtf文件？

Dim app As New MSWord.Application
try
    Dim fileName = "e:\test.docx"
    app.Documents.Open(fileName)

    app.

catch ex As exception
    msgbox(ex.message)
finally
    app.Quit
End try