Dim app As New MSWord.Application

Try

    Dim dlg As New OpenFileDialog \'定义一个新的OpenFileDialog

    dlg.Filter = "Word文件|*.doc;*.docx" \'设置筛选器

    If dlg.ShowDialog = DialogResult.Ok Then \'如果用户单击了确定按钮

        MessageBox.Show("你选择的是:" & dlg.FileName,"提示") \'提示用户选择的文件

        Dim doc = app.Documents.Open(dlg.FileName)

        Dim str As String = FileSys.GetName(dlg.FileName)

        Dim filt As String = str.SubString(0,str.LastIndexOf("."))

        Dim pth As String = SpecialFolder.DesktopDirectory & filt & ".pdf"

        msgbox(pth)

        app.Documents(dlg.FileName).ExportAsFixedFormat(pth, MSWord.WdExportFormat.wdExportFormatPDF)

        app.Quit

    End If

Catch ex As Exception

    msgbox(ex.message)

    app.Quit

End Try