Private Sub fillPdfButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles fillPdfButton.Click
    Cursor = Cursors.WaitCursor

    Dim outPdfFile As String = "DemoAppFiles\Output\PDF_Editor\Filled_PDF_Form.pdf"
    Dim pdfDocument As Document = Nothing
    Try
        ' Load the PDF document with a form to fill
        pdfDocument = New Document(pdfFileWithForm)

        ' Set license key received after purchase to use the converter in licensed mode
        ' Leave it not set to use the converter in demo mode
        pdfDocument.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og="

        ' Get the First Name text box field by name from PDF form fields collection and fill a text value
        Dim firstNameTextBoxField As PdfFormField = pdfDocument.Form.Fields("firstName")
        If firstNameTextBoxField IsNot Nothing Then
            firstNameTextBoxField.Value = firstNameTextBox.Text
        End If

        ' Get the Last Name text box field by name from PDF form fields collection and fill a text value
        Dim lastNameTextBoxField As PdfFormField = pdfDocument.Form.Fields("lastName")
        If lastNameTextBoxField IsNot Nothing Then
            lastNameTextBoxField.Value = lastNameTextBox.Text
        End If

        ' Get the Password text box field by name from PDF form fields collection and fill a text value
        Dim passwordTextBoxField As PdfFormField = pdfDocument.Form.Fields("password")
        If passwordTextBoxField IsNot Nothing Then
            passwordTextBoxField.Value = passwordTextBox.Text
        End If

        ' Get the Gender radio buttons group field by name from form fields collection and set the selected value
        Dim genderRadioGroupField As PdfFormField = pdfDocument.Form.Fields("gender")
        If genderRadioGroupField IsNot Nothing Then
            genderRadioGroupField.Value = If(maleRadioButton.Checked, "male", "female")
        End If

        ' Get the 'I have a car' check box field by name from form fields collection and set the checked status
        Dim haveCarCheckBoxField As PdfFormField = pdfDocument.Form.Fields("haveCar")
        If haveCarCheckBoxField IsNot Nothing Then
            haveCarCheckBoxField.Value = haveCarCheckBox.Checked
        End If

        ' Get the 'Vehicle Type' combo box field by name from form fields collection and set the selected value
        Dim vehicleTypeComboBoxField As PdfFormField = pdfDocument.Form.Fields("vehicleType")
        If vehicleTypeComboBoxField IsNot Nothing Then
            vehicleTypeComboBoxField.Value = carTypeComboBox.SelectedItem
        End If

        ' Get the Comments multi line text box field by name from PDF form fields collection and fill a text value
        Dim commentsTextBoxField As PdfFormField = pdfDocument.Form.Fields("comments")
        If commentsTextBoxField IsNot Nothing Then
            commentsTextBoxField.Value = commentsTextBox.Text
        End If

        ' Flatten PDF form fields if this was requested
        If flattenPdfFormCheckBox.Checked Then
            pdfDocument.Form.FlattenFields()
        End If

        ' Save the PDF document in a memory buffer
        Dim outPdfBuffer() As Byte = pdfDocument.Save()

        ' Write the memory buffer in a PDF file
        System.IO.File.WriteAllBytes(outPdfFile, outPdfBuffer)
    Catch ex As Exception
        ' The PDF creation failed
        MessageBox.Show(String.Format("Create PDF Document Error. {0}", ex.Message))
        Return
    Finally
        ' Close the document to stamp
        If pdfDocument IsNot Nothing Then
            pdfDocument.Close()
        End If

        Cursor = Cursors.Arrow
    End Try

    ' Open the created PDF document in default PDF viewer
    Try
        Process.Start(outPdfFile)
    Catch ex As Exception
        MessageBox.Show(String.Format("Cannot open created PDF file '{0}'. {1}", outPdfFile, ex.Message))
    End Try
End Sub