在.NET 2.0+中针对PayPal API进行编码的示例？

Install-Package PayPal

using PayPal.Api;
using System.Threading.Tasks;
using System.Web.Http;

public class PayPalController : ApiController
{
    [HttpPost]
    public async Task<IHttpActionResult> ProcessPayment([FromBody] Payment payment)
    {
        // 创建PayPal API上下文
        var apiContext = new APIContext
        {
            AccessToken = "your_access_token",
            Config = new Dictionary<string, string>
            {
                { "mode", "sandbox" }
            }
        };

        // 创建支付请求
        var paymentRequest = new Payment
        {
            intent = "sale",
            payer = new Payer
            {
                payment_method = "paypal"
            },
            transactions = new List<Transaction>
            {
                new Transaction
                {
                    amount = new Amount
                    {
                        currency = "USD",
                        total = "10.00"
                    },
                    description = "This is a test payment."
                }
            },
            redirect_urls = new RedirectUrls
            {
                cancel_url = "https://yourwebsite.com/cancel",
                return_url = "https://yourwebsite.com/success"
            }
        };

        // 发送支付请求
        var createdPayment = await paymentRequest.CreateAsync(apiContext);

        // 获取支付链接
        var approvalUrl = createdPayment.links.FirstOrDefault(x => x.rel.Equals("approval_url"))?.href;

        // 返回支付链接
        return Ok(approvalUrl);
    }
}