C# 如何创建加密的PayNow按钮“；“在飞行中”；对于第三方客户，是否使用Paypal NVP API？_C#_Asp.net_Vb.net_Paypal

C# 如何创建加密的PayNow按钮“；“在飞行中”；对于第三方客户，是否使用Paypal NVP API？

c# asp.net vb.net paypal

C# 如何创建加密的PayNow按钮“；“在飞行中”；对于第三方客户，是否使用Paypal NVP API？,c#,asp.net,vb.net,paypal,C#,Asp.net,Vb.net,Paypal,我需要为网站动态创建加密的“PayNow”paypal按钮。我阅读了贝宝网站上的所有文档。我知道我需要使用BMCreateButton ButtonManager NVP API。但是我找不到任何关于如何调用这些API的信息，也找不到任何合理简单且有文档记录的示例代码我是否需要将参数放入表单并发布到某种服务器上？我是否需要将所有参数放在url上，调用此url，并使用结果？如何对此服务进行身份验证？我将为不同的paypal业务帐户创建加密的paynow按钮有人能给我看一些VB.Ne

我需要为网站动态创建加密的“PayNow”paypal按钮。
我阅读了贝宝网站上的所有文档。
我知道我需要使用BMCreateButton ButtonManager NVP API。
但是我找不到任何关于如何调用这些API的信息，也找不到任何合理简单且有文档记录的示例代码

我是否需要将参数放入表单并发布到某种服务器上？
我是否需要将所有参数放在url上，调用此url，并使用结果？
如何对此服务进行身份验证？
我将为不同的paypal业务帐户创建加密的paynow按钮

有人能给我看一些VB.Net或C#代码，它们实际上调用了这个BMCreateButton NVP API吗？
这样我就可以看到：

怎么打电话
如何对服务进行身份验证
如何格式化/使用API调用的参数
如何获得结果

有用资源的各种链接
-感谢您的帮助，我找到了一些有用的示例代码以及关于如何调用Paypal API的内容。
-是关于paypal NVP API如何工作的更有用的信息。
-为BMCreateButton API生成API调用URL的有趣网站
-您可以找到获取“第三方”API凭据的说明。（感谢）
-有关Paypal API集成的更多有用信息
-您可以找到Paypal API的当前和最新版本号

更新1
现在我已经创建了一些代码，这些代码实际上做了一些事情，但是它给了我一个错误。这段代码实际上使用BMCreateButton API创建了一个加密的paynow按钮。它似乎可以工作，但当我单击paynow按钮时，它会显示所有付款参数，但也会显示错误 “您的安全订单解密有问题。请与您的商户联系。”

以下是代码：

以下是HTML响应

<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="encrypted" value="-----BEGIN PKCS7-----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-----END PKCS7-----
">
<input type="image" src="https://www.sandbox.paypal.com/en_US/i/btn/btn_buynow_LG.gif" border="0" name="submit" alt="PayPal - Il sistema di pagamento online più facile e sicuro!">
<img alt="" border="0" src="https://www.sandbox.paypal.com/it_IT/i/scr/pixel.gif" width="1" height="1">
</form>

这是我点击这个加密的“立即付款”按钮后得到的错误

如您所见，所有参数（项目名称、价格、项目id…）都是正确的。但我无法理解为什么我会犯这个错误

如果你想尝试这段代码，你应该替换你的API用户/密码/签名。生成的PayNow按钮仅在您登录paypal沙盒帐户时有效

你知道如何解决这个错误吗

注意：解决此问题后，我需要了解如何为第三个paypal业务帐户创建加密按钮（我们需要为客户的paypal帐户创建加密按钮）。使用我们的API凭据、客户商户代码以及在客户paypal帐户中配置我们的API凭据是不够的。。。上面说商户代码无效。也许我错过了什么

更新2
似乎我已经找到了解决上述错误的方法：只需删除“cmd=\u s-xclick/\u xclick”参数。如果未指定“cmd”，则paynow按钮似乎不会生成任何错误。需要更多的测试。。。无论如何，我已经在代码示例中注释了代码行

现在，回到正题上来。让我们做一些测试，然后找到为第三方paypal帐户创建paynow按钮的正确方法。

好的，终于找到了！：-）

我的目标是为我们的一些客户“即时”创建加密的PayNow按钮。 下面简要说明PayPal API如何与第三方访问配合使用

创建Paypal沙盒帐户（）
在此沙箱帐户中，创建2个新的业务帐户
你应该把这些商业帐户挂在信用卡上。这会将这些帐户标记为“已验证”，除非它不起作用
- 第一个账户（账户A）将代表我们公司
- 第二个帐户（帐户B）将代表我们的一个客户
登录帐户A，并请求API凭据（）
登录帐户B，并向帐户A授予API权限（查看“第三方身份验证：向您的购物车授予适当的API身份验证权限”一段）
获取帐户A的Api凭据，并将其放入源代码中
抓取帐户B的商户ID和商户电子邮件，并将其放入您的源代码中
运行代码
抓取返回的html，将其放在网页上，并对其进行测试，它应该可以工作
（您需要登录您的paypal沙盒帐户，否则生成的按钮无法工作）

为什么这些简单而简洁的知识在无数的PayPal帮助页面、PayPal PDF手册和第三方博客文章中时不时地被分散，这超出了我的理解：-）无论如何

下面是VB.Net中的工作代码

这里是C#中的相同代码

公共静态无效PaypalThirdPartyPayNowButtonTest（）
{
int bvCount=0；//L_按钮VAR计数器
Dictionary NVP=new Dictionary（）；//Api名称-值对参数
//贝宝沙盒服务器
字符串paypalApiServerUrl=”https://api-3t.sandbox.paypal.com/nvp";
//您的企业paypal帐户的Api凭据
string yourApiUsername=“aso_1273063882_biz_api3.megatesto.it”；
字符串yourApiPassword=“1273063582”；
字符串yourApiSignature=“A22sd7623RGUsduDHDSFU57N7dfhfS23DUYVhdf85du8S6FJ6D5bfoh5”；
//您的客户识别数据
字符串customerEmailID=“MyCustomer\u 143363961_biz@megatesto.it";
字符串customermanchandi=“3S4EF7BI96YHS”；
//使用你的身份资料
添加（“用户”，即用户名）；
NVP.Add（“PWD”，密码）；
NVP.添加（“签名”，即签名）；
//使用您的客户标识
<form action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_s-xclick">
<input type="hidden" name="encrypted" value="-----BEGIN PKCS7-----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-----END PKCS7-----
">
<input type="image" src="https://www.sandbox.paypal.com/en_US/i/btn/btn_buynow_LG.gif" border="0" name="submit" alt="PayPal - Il sistema di pagamento online più facile e sicuro!">
<img alt="" border="0" src="https://www.sandbox.paypal.com/it_IT/i/scr/pixel.gif" width="1" height="1">
</form>

Public Shared Sub PaypalThirdPartyPayNowButtonTest()
    Dim bvCount As Integer = 0  ''L_BUTTONVAR counter
    Dim NVP As New Dictionary(Of String, String)  ''Api Name-Value-Pair parameters

    ''define paypal SANDBOX server
    Dim paypalApiServerUrl As String = "https://api-3t.sandbox.paypal.com/nvp"

    ''define Api credentials of YOUR business paypal account 
    Dim yourApiUsername As String = "aso_1273063882_biz_api3.megatesto.it"
    Dim yourApiPassword As String = "1273063582"
    Dim yourApiSignature As String = "A22sd7623RGUsduDHDSFU57N7dfhfS23DUYVhdf85du8S6FJ6D5bfoh5"

    ''define Your CUSTOMER identification data
    Dim customerEmailID As String = "MyCustomer_143363961_biz@megatesto.it"
    Dim customerMerchantID As String = "3S4EF7BI96YHS"


    ''use YOUR identification data
    NVP.Add("USER", yourApiUsername)
    NVP.Add("PWD", yourApiPassword)
    NVP.Add("SIGNATURE", yourApiSignature)

    ''use your CUSTOMER identification data
    NVP.Add("SUBJECT", customerEmailID)
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "business=" & customerMerchantID) ''Merchant ID


    ''Api method name and version
    NVP.Add("METHOD", "BMCreateButton")
    NVP.Add("VERSION", "85.0")

    ''method specific parameters
    NVP.Add("BUTTONCODE", "ENCRYPTED")
    NVP.Add("BUTTONTYPE", "BUYNOW")
    NVP.Add("BUTTONSUBTYPE", "PRODUCTS")

    ''Buynow button specific parameters
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "lc=IT")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "button_subtype=PRODUCTS")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "item_name=Test_product")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "item_number=123456")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "amount=12.00")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "currency_code=EUR")
    bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "quantity=1")
    ''bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "cmd=_s-xclick")  'DONT' specify the cmd parameter, if you specify it, it wont work, paypal will give you an error

    ''build the parameter string
    Dim paramBuilder As New StringBuilder
    For Each kv As KeyValuePair(Of String, String) In NVP
        Dim st As String
        st = kv.Key & "=" & HttpUtility.UrlEncode(kv.Value) & "&"
        paramBuilder.Append(st)
    Next

    Dim param As String
    param = paramBuilder.ToString
    param = param.Substring(0, param.Length - 1) ''remove the last '&'


    ''Create web request and web response objects, make sure you using the correct server (sandbox/live)
    Dim wrWebRequest As HttpWebRequest = DirectCast(WebRequest.Create(paypalApiServerUrl), HttpWebRequest)
    wrWebRequest.Method = "POST"


    Dim requestWriter As New StreamWriter(wrWebRequest.GetRequestStream())
    requestWriter.Write(param)
    requestWriter.Close()

    '' Get the responseReader
    Dim responseReader As StreamReader
    responseReader = New StreamReader(wrWebRequest.GetResponse().GetResponseStream())

    ''read the response
    Dim responseData As String
    responseData = responseReader.ReadToEnd()
    responseReader.Close()


    ''url-decode the results
    Dim result As String
    result = HttpUtility.UrlDecode(responseData)

    Dim formattedResult As String

    formattedResult = "Request on " & paypalApiServerUrl & vbCrLf &
                     HttpUtility.UrlDecode(param.Replace("&", vbCrLf & "  ")) & vbCrLf & vbCrLf &
                     "Result:" & vbCrLf & HttpUtility.UrlDecode(responseData.Replace("&", vbCrLf & "  ")) & vbCrLf & vbCrLf &
                     "--------------------------------------" & vbCrLf

    ''show the results
    Trace.WriteLine(formattedResult)
    MessageBox.Show(formattedResult)
End Sub

public static void PaypalThirdPartyPayNowButtonTest()
{
    int bvCount = 0; //L_BUTTONVAR counter
    Dictionary<string, string> NVP = new Dictionary<string, string>(); //Api Name-Value-Pair parameters

    //paypal SANDBOX server
    string paypalApiServerUrl = "https://api-3t.sandbox.paypal.com/nvp";

    //Api credentials of YOUR business paypal account 
    string yourApiUsername = "aso_1273063882_biz_api3.megatesto.it";
    string yourApiPassword = "1273063582";
    string yourApiSignature = "A22sd7623RGUsduDHDSFU57N7dfhfS23DUYVhdf85du8S6FJ6D5bfoh5";

    //Your CUSTOMER identification data
    string customerEmailID = "MyCustomer_143363961_biz@megatesto.it";
    string customerMerchantID = "3S4EF7BI96YHS";

    //use YOUR identification data
    NVP.Add("USER", yourApiUsername);
    NVP.Add("PWD", yourApiPassword);
    NVP.Add("SIGNATURE", yourApiSignature);

    //use your CUSTOMER identification data
    NVP.Add("SUBJECT", customerEmailID);
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "business=" + customerMerchantID);

    //Api method name and version
    NVP.Add("METHOD", "BMCreateButton");
    NVP.Add("VERSION", "85.0");

    //method specific parameters
    NVP.Add("BUTTONCODE", "ENCRYPTED");
    NVP.Add("BUTTONTYPE", "BUYNOW");
    NVP.Add("BUTTONSUBTYPE", "PRODUCTS");

    //Buynow button specific parameters
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "lc=IT");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "button_subtype=PRODUCTS");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "item_name=Test_product");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "item_number=123456");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "amount=12.00");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "currency_code=EUR");
    bvCount++; NVP.Add("L_BUTTONVAR" + bvCount.ToString() , "quantity=1");
    //bvCount = bvCount + 1 : NVP.Add("L_BUTTONVAR" & bvCount, "cmd=_s-xclick")  //DON'T specify the cmd parameter, if you specify it, it wont work, paypal will give you an error


    //build the parameter string
    StringBuilder paramBuilder = new StringBuilder();
    foreach (KeyValuePair<string, string> kv in NVP)
    {
        string st = kv.Key + "=" + System.Web.HttpUtility.UrlEncode(kv.Value) + "&";
        paramBuilder.Append(st);
    }

    string param = paramBuilder.ToString();
    param = param.Substring(0, param.Length - 1); //remove the last '&'


    //Create web request and web response objects, make sure you using the correct server (sandbox/live)
    System.Net.HttpWebRequest wrWebRequest = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(paypalApiServerUrl);
    wrWebRequest.Method = "POST";

    System.IO.StreamWriter requestWriter = new System.IO.StreamWriter(wrWebRequest.GetRequestStream());
    requestWriter.Write(param);
    requestWriter.Close();


    //Get the responseReader
    System.IO.StreamReader responseReader = new System.IO.StreamReader(wrWebRequest.GetResponse().GetResponseStream());
    string responseData = responseReader.ReadToEnd();
    responseReader.Close();

    //url-decode the results
    string result = System.Web.HttpUtility.UrlDecode(responseData);

    string formattedResult = "Request on " + paypalApiServerUrl + "\r\n" + System.Web.HttpUtility.UrlDecode(param.Replace("&", "\r\n  ")) + "\r\n\r\nResult:\r\n" + System.Web.HttpUtility.UrlDecode(responseData.Replace("&", "\r\n  ")) + "\r\n\r\n--------------------------------------\r\n";

    //show the results
    System.Diagnostics.Trace.WriteLine(formattedResult);
    System.Windows.Forms.MessageBox.Show(formattedResult);
}