[VB / C#] มีใครเคยใช้ VB หรือ C# เชื่อมต่อกับ PAYMENT GATEWAY ต่างๆ เช่น PAYSBUY LINEPAY บ้างมั้ยครับ

Imports System.Net
Imports System.IO
Imports System.Text
Public Class Form1

    Private Sub btnPayment_Click(sender As Object, e As EventArgs) Handles btnPayment.Click
        Dim request As WebRequest
        Dim Site As String = "https://www.paysbuy.com/paynow.aspx?"
        request = WebRequest.Create(Site)
        Dim response As WebResponse
        Dim psb As String = "psb"
        Dim biz As String = "[email protected]"
        Dim inv As String = "TEST001"
        Dim itm As String = "ทดสอบ Payment Gateway"
        Dim amt As Double = 50
        Dim postURL As String = ""
        'Dim reqURL As String = ""
        'Dim cCode As String = "บาท"
        Dim postData As String = "psb=" & psb & "&biz=" & biz & "&inv=" & inv & "&itm=" & itm & "&amt=" & amt & "&postURL=" & postURL
        MessageBox.Show(postData)
        Dim data As Byte() = Encoding.UTF8.GetBytes(postData)


        request.Method = "POST"
        request.ContentType = "application/x-www-form-urlencoded"
        request.ContentLength = data.Length

        Dim stream As Stream = request.GetRequestStream()
        WebBrowser1.DocumentStream = stream
        stream.Write(data, 0, data.Length)
        stream.Close()

        response = request.GetResponse()
        Dim sr As New StreamReader(response.GetResponseStream())

        Dim paysbuy As String = sr.ReadToEnd()

        TextBox1.Text = paysbuy
        'WebBrowser1.DocumentText = paysbuy
    End Sub
End Class

<!--CONTENT START-->
                <div class="error-page-main text-center barcodebody">
                    <p id="msg" class="font-red text-bold">Payment not allowed less than 1 Baht per transaction</p>                    
                    <p class="text-center top-space10">
                        <center>
                            <input type="submit" name="nextBT" value="Done" id="nextBT" class="btn-finish-longN" />
                           
                        </center>
                    </p>
                    <p id="show_time" class="left-space10"></p>
                </div>
               
                <!--CONTENT END-->