主题：关于读取PDF文件的问题2

Dim dlg As New OpenFileDialog

dlg.Filter = "图像文件|*.pdf"

dlg.InitialDirectory = ProjectPath

If dlg.ShowDialog = DialogResult.Ok Then

    Dim txt As WinForm.TextBox = e.Form.Controls("TextBox1")

    txt.Text = "使用图像文件: " & dlg.FileName

    Try

        Dim client As new Baidu.Aip.Ocr.Ocr(Vars("APIKey"), Vars("SecretKey")) '初始化接口类,传入创建的应用的API Key,Secret Key

        client.Timeout = 60000 '设置超时时间

        Dim data() As Byte = System.IO.File.ReadAllBytes(dlg.FileName) '把图片文件字节流加载进来,

        Dim d As String = Convert.ToBase64String(data)

        Dim options As New Dictionary(Of String, Object) '使用字典传递参数

        options.Add("Content-Type", "application/x-www-form-urlencoded")

        options.add("pdf_file", d)

        Dim result = client.VatInvoicePdf(data, options) '调用接口开始识别,返回值为JObject对象

        If result("error_code") IsNot Nothing AndAlso result("error_code") <> 0 Then

            txt.text = "识别失败: " & vbcrlf & result("error_msg").Tostring

        Else

            txt.text = txt.text & vbcrlf & "--------************-----------"

            txt.text = txt.text & vbcrlf & "识别出" & result("words_result_num").Tostring & "个句子/短语:"

            Dim ja As JArray = result("words_result")

            For i As Integer = 0 To ja.Count - 1

                txt.text = txt.text & vbcrlf & ja(i)("words").Tostring

            Next

        End If

    Catch ex As exception

        txt.text = txt.text & vbcrlf & "识别接口调用失败,错误描述: " &  vbcrlf & ex.message

    End try

End If