开发环境Visual Studio 2015,Xamarin 3.11.1537,Xamarin Android5.1.7.12

下载支付宝移动支付的SDK（http://doc.open.alipay.com/doc2/detail?treeId=54&articleId=103419&docType=1），找到Andriud的SDK，其中有一个alipaySDK-20151014.jar（这个版本，以后肯定会变化），这是我们使用的重点。

• 在Visual Studio中创建一个绑定库文件

  

  把支付宝的alipaySDK-20151014.jar添加到Jars文件夹下，先中alipaySDK-20151014.jar，打开属性窗口，设置生成操作为EmbeddedJar，库文件搞定。

• Android中使用绑定库文件

  在Visual Studio中创建一个BlankApp应用，然后在打开项目属性，Android Manifest选项卡，在Required permissions中选择ACCESS_WIFI_STATE和INTERNET权限，添加绑定库生成的dll到当前项目的引用中。

  添加签名生成类

using System;
using System.Text;
using System.IO;
using System.Security.Cryptography;namespace App1
{class SignatureUtils{/// <summary>/// 签名/// </summary>/// <param name="content">需要签名的内容</param>/// <param name="privateKey">私钥</param>/// <returns></returns>public static string Sign(string content, string privateKey){      byte[] Data = Encoding.GetEncoding("utf-8").GetBytes(content);RSACryptoServiceProvider rsa = DecodePemPrivateKey(privateKey);SHA1 sh = new SHA1CryptoServiceProvider();byte[] signData = rsa.SignData(Data, sh);sh.Clear();return Convert.ToBase64String(signData);}/// <summary>/// 对prikey进行处理，C#API默认的prikey是xml格式的，所以需要进行处理/// </summary>/// <param name="pemstr"></param>/// <returns></returns>private static RSACryptoServiceProvider DecodePemPrivateKey(String pemstr){byte[] pkcs8privatekey;pkcs8privatekey = Convert.FromBase64String(pemstr);if (pkcs8privatekey != null){RSACryptoServiceProvider rsa = DecodePrivateKeyInfo(pkcs8privatekey);return rsa;}elsereturn null;}/// <summary>/// 转换prikey/// </summary>/// <param name="pkcs8"></param>/// <returns></returns>private static RSACryptoServiceProvider DecodePrivateKeyInfo(byte[] pkcs8){byte[] SeqOID = { 0x30, 0x0D, 0x06, 0x09, 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x01, 0x01, 0x01, 0x05, 0x00 };byte[] seq = new byte[15];MemoryStream mem = new MemoryStream(pkcs8);int lenstream = (int)mem.Length;BinaryReader binr = new BinaryReader(mem);  byte bt = 0;ushort twobytes = 0;try{twobytes = binr.ReadUInt16();if (twobytes == 0x8130) binr.ReadByte();   else if (twobytes == 0x8230)binr.ReadInt16();  elsereturn null;bt = binr.ReadByte();if (bt != 0x02)return null;twobytes = binr.ReadUInt16();if (twobytes != 0x0001)return null;seq = binr.ReadBytes(15);      if (!CompareBytearrays(seq, SeqOID))   return null;bt = binr.ReadByte();if (bt != 0x04) return null;bt = binr.ReadByte();      if (bt == 0x81)binr.ReadByte();elseif (bt == 0x82)binr.ReadUInt16();byte[] rsaprivkey = binr.ReadBytes((int)(lenstream - mem.Position));RSACryptoServiceProvider rsacsp = DecodeRSAPrivateKey(rsaprivkey);return rsacsp;}catch (Exception){return null;}finally { binr.Close(); }}private static bool CompareBytearrays(byte[] a, byte[] b){if (a.Length != b.Length)return false;int i = 0;foreach (byte c in a){if (c != b[i])return false;i++;}return true;}/// <summary>/// 处理私钥/// </summary>/// <param name="privkey"></param>/// <returns></returns>private static RSACryptoServiceProvider DecodeRSAPrivateKey(byte[] privkey){byte[] MODULUS, E, D, P, Q, DP, DQ, IQ;MemoryStream mem = new MemoryStream(privkey);BinaryReader binr = new BinaryReader(mem);   byte bt = 0;ushort twobytes = 0;int elems = 0;try{twobytes = binr.ReadUInt16();if (twobytes == 0x8130) binr.ReadByte();    else if (twobytes == 0x8230)binr.ReadInt16();   elsereturn null;twobytes = binr.ReadUInt16();if (twobytes != 0x0102) return null;bt = binr.ReadByte();if (bt != 0x00)return null;elems = GetIntegerSize(binr);MODULUS = binr.ReadBytes(elems);elems = GetIntegerSize(binr);E = binr.ReadBytes(elems);elems = GetIntegerSize(binr);D = binr.ReadBytes(elems);elems = GetIntegerSize(binr);P = binr.ReadBytes(elems);elems = GetIntegerSize(binr);Q = binr.ReadBytes(elems);elems = GetIntegerSize(binr);DP = binr.ReadBytes(elems);elems = GetIntegerSize(binr);DQ = binr.ReadBytes(elems);elems = GetIntegerSize(binr);IQ = binr.ReadBytes(elems);CspParameters cspParams = new CspParameters();cspParams.Flags = CspProviderFlags.UseMachineKeyStore;//System.Security.Cryptography.RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(1024, cspParams); RSACryptoServiceProvider RSA = new RSACryptoServiceProvider(1024);RSAParameters RSAparams = new RSAParameters();RSAparams.Modulus = MODULUS;RSAparams.Exponent = E;RSAparams.D = D;RSAparams.P = P;RSAparams.Q = Q;RSAparams.DP = DP;RSAparams.DQ = DQ;RSAparams.InverseQ = IQ;RSA.ImportParameters(RSAparams);return RSA;}catch (Exception){return null;}finally { binr.Close(); }}/// <summary>/// 获取binr的长度/// </summary>/// <param name="binr"></param>/// <returns></returns>private static int GetIntegerSize(BinaryReader binr){byte bt = 0;byte lowbyte = 0x00;byte highbyte = 0x00;int count = 0;bt = binr.ReadByte();if (bt != 0x02)     return 0;bt = binr.ReadByte();if (bt == 0x81)count = binr.ReadByte();    elseif (bt == 0x82){highbyte = binr.ReadByte(); lowbyte = binr.ReadByte();byte[] modint = { lowbyte, highbyte, 0x00, 0x00 };count = BitConverter.ToInt32(modint, 0);}else{count = bt;     }while (binr.ReadByte() == 0x00){   count -= 1;}binr.BaseStream.Seek(-1, SeekOrigin.Current);       return count;}}
}

在主程序中添加如下代码：

using System;
using Android.App;
using Android.Widget;
using Android.OS;
using Java.Net;namespace App1
{[Activity(Label = "App1", MainLauncher = true)]public class MainActivity : Activity{ // 合作商户ID。用签约支付宝账号登录ms.alipay.com后，在账户信息页面获取。public static string PARTNER = "替换你支付宝申请的partner";// 商户收款的支付宝账号public static string SELLER = "替换你支付宝申请的seller";//商户私密string RSA_PRIVATE = "替换你支付宝申请的private_key";
;protected override void OnCreate(Bundle bundle){base.OnCreate(bundle);SetContentView(Resource.Layout.Main);Button button = FindViewById<Button>(Resource.Id.MyButton);button.Click += HandleClick;}void HandleClick(object sender, EventArgs e){System.Threading.Thread the = new System.Threading.Thread(Pay);the.Start();}void Pay(){ var con = getOrderInfo("test", "testbody");var sign = SignatureUtils.Sign(con, RSA_PRIVATE);sign = URLEncoder.Encode(sign, "utf-8");con += "&sign=\"" + sign + "\"&" + MySignType;Com.Alipay.Sdk.App.PayTask pa = new Com.Alipay.Sdk.App.PayTask(this);var result = pa.Pay(con);//调用结果查看result中是否返回是90000,如果是，则成功      }#region 组合public String getOrderInfo(String subject, String body){ // 签约合作者身份IDString orderInfo = "partner=" + "\"" + PARTNER + "\""; // 签约卖家支付宝账号orderInfo += "&seller_id=" + "\"" + SELLER + "\""; // 商户网站唯一订单号orderInfo += "&out_trade_no=" + "\"DJ" + DateTime.Now.ToString("yyyyMMddhhmmss") + "\""; // 商品名称orderInfo += "&subject=" + "\"" + subject + "\""; // 商品详情orderInfo += "&body=" + "\"" + body + "\""; // 商品金额orderInfo += "&total_fee=" + "\"" + 0.01 + "\""; // 服务器异步通知页面路径orderInfo += "&notify_url=" + "\"" + "http://notify.msp.hk/notify.htm"+ "\""; // 服务接口名称， 固定值

orderInfo +="&service=\"mobile.securitypay.pay\"";

//支付类型，固定值

orderInfo +="&payment_type=\"1\"";

//参数编码，固定值

orderInfo +="&_input_charset=\"utf-8\"";

//设置未付款交易的超时时间

//默认30分钟，一旦超时，该笔交易就会自动被关闭。

//取值范围：1m～15d。

// m-分钟，h-小时，d-天，1c-当天（无论交易何时创建，都在0点关闭）。

//该参数数值不接受小数点，如1.5h，可转换为90m。

orderInfo +="&it_b_pay=\"30m\"";

// extern_token为经过快登授权获取到的alipay_open_id,带上此参数用户将使用授权的账户进行支付

// orderInfo += "&extern_token=" + "\"" + extern_token + "\"";

//支付宝处理完请求后，当前页面跳转到商户指定页面的路径，可空

orderInfo +="&return_url=\"m.alipay.com\"";

//调用银行卡支付，需配置此参数，参与签名，固定值（需要签约《无线银行卡快捷支付》才能使用）

// orderInfo += "&paymethod=\"expressGateway\"";

returnorderInfo;

}

publicStringMySignType

{

get

{

return"sign_type=\"RSA\"";

}

}

#endregion

}

}

源代码见附件