The document contains code snippets for making API calls to PayPal to facilitate different parts of an Express Checkout transaction flow. The code handles setting up an Express Checkout transaction, getting details of an Express Checkout transaction, and completing payment for an Express Checkout transaction. It also includes code for setting up a billing agreement and reference transactions.

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8. protected void DoSetEC(object sender, EventArgs e)
{
try
{
caller = new NVPCallerServices();
setProfile(MyProfile, “APIUsername”,”APIPassword”,”APISignature”);
MyCodec["METHOD"] = "SetExpressCheckout";
MyCodec["VERSION"] = “82“;
MyCodec["CANCELURL"] = ”MyCancelURL";
MyCodec["RETURNURL"] = ”MyReturnURL”;
MyCodec["PAYMENTREQUEST_0_CURRENCYCODE"] = "GBP";
MyCodec["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";
MyCodec["L_PAYMENTREQUEST_0_NAME0"] = ”Item in my Shopping cart";
MyCodec["L_PAYMENTREQUEST_0_AMT0"] = "24.48";
MyCodec["L_PAYMENTREQUEST_0_QTY0"] = "2”;
MyCodec["PAYMENTREQUEST_0_ITEMAMT"] = "43.96";
MyCodec["PAYMENTREQUEST_0_SHIPPINGAMT"] = "1.50";
MyCodec["PAYMENTREQUEST_0_AMT"] = ”45.46”
caller.Initialize();
caller.APIProfile = MyProfile;
MyNVPRequest = MyCodec.Encode();
MyNVPResponse = caller.Call(MyNVPRequest);
MyRespoCodec.Decode(MyNVPResponse);
if (MyRespoCodec["ACK"] != "Success" && MyRespoCodec["ACK"] != "SUCCESSWITHWARNING")
{ /*display error message*/}
else
{
MyToken = MyRespoCodec["TOKEN"].ToString();
Response.Redirect(@"https://www.sandbox.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token=" + MyToken);
}
}
catch (Exception exp)
{/*sort out exceptions*/}
}

9. protected void DoGetEC(string token, string PayerID)
{
try
{
caller = new NVPCallerServices();
setProfile(MyProfile, “APIUsername”,”APIPassword”,”APISignature”);
MyCodec["METHOD"] = "GetExpressCheckoutDetails";
MyCodec["TOKEN"] = MyToken;
caller.Initialize();
caller.APIProfile = MyProfile;
MyNVPRequest = MyCodec.Encode();
MyNVPResponse = caller.Call(MyNVPRequest);
MyRespoCodec.Decode(MyNVPResponse);
if (MyRespoCodec["ACK"] != "Success" && MyRespoCodec["ACK"] != "SUCCESSWITHWARNING")
{ /*display error message*/}
else
{/*Get information on the buyer and the transaction*/
CollectShippingDetails(MyRespoCodec[”SHIPPTONAME"], MyRespoCodec[”SHIPTOSTREET1"], MyRespoCodec[”SHIPTOSTREET2”], MyRespoCodec[”SHIPTOCITY”],
MyRespoCodec[”SHIPTOPOSTALCODE"], MyRespoCodec[”SHIPTOCOUNTRY"]);
}
}
catch (Exception exp)
{/*sort out exceptions*/}
}

10. protected void DoECPayment(string token, string PayerID)
{
try
{
caller = new NVPCallerServices();
setProfile(MyProfile, “APIUsername”,”APIPassword”,”APISignature”);
MyCodec["METHOD"] = "DoExpressCheckoutPayment";
MyCodec["TOKEN"] = token;
MyCodec["PAYERID"] = PayerID;
MyCodec["PAYMENTACTION"] = "Sale";
MyCodec["CURRENCYCODE"] = “GBP”;
MyCodec["AMT"] = "39.90";
caller.Initialize();
caller.APIProfile = MyProfile;
MyNVPRequest = MyCodec.Encode();
MyNVPResponse = caller.Call(MyNVPRequest);
MyRespoCodec.Decode(MyNVPResponse);
if (MyRespoCodec["ACK"] != "Success" && MyRespoCodec["ACK"] != "SUCCESSWITHWARNING")
{ /*display error message*/}
else
{/*Get information on the payment status*/
TxnID = MyRespoCodec[”TRANSACTIONID"] ;
if (MyRespoCodec[”PAYMENTSTATUS"] != “Completed”)
{/*Handle Incomplete transaction*/}
else {/*Fulfill order*/}
}
}
catch (Exception exp)
{/*sort out exceptions*/}
}

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13. protected void DoSetEC(object sender, EventArgs e)
{
try
{
caller = new NVPCallerServices();
setProfile(MyProfile, “APIUsername”,”APIPassword”,”APISignature”);
MyCodec["METHOD"] = "SetExpressCheckout";
MyCodec["VERSION"] = “82“;
MyCodec["CANCELURL"] = ”MyCancelURL";
MyCodec["RETURNURL"] = ”MyReturnURL”;
MyCodec["PAYMENTREQUEST_0_CURRENCYCODE"] = ”USD";
MyCodec["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";
MyCodec["PAYMENTREQUEST_0_SELLERID"] = ”paypal@bookit.com”;
MyCodec["L_PAYMENTREQUEST_0_NAME0"] = ”Booking for my hotel";
MyCodec["L_PAYMENTREQUEST_0_AMT0"] = ”423.35";
MyCodec["L_PAYMENTREQUEST_0_QTY0"] = “1”;
MyCodec["PAYMENTREQUEST_0_ITEMAMT"] = ”423.35";
MyCodec["PAYMENTREQUEST_0_AMT"] = ”423.35”
MyCodec["PAYMENTREQUEST_1_CURRENCYCODE"] = ”USD";
MyCodec["PAYMENTREQUEST_1_PAYMENTACTION"] = "Sale”;
MyCodec["PAYMENTREQUEST_1_SELLERID"] = ”paypal@usairlines.com”;
MyCodec["L_PAYMENTREQUEST_1_NAME0"] = ”Plane tickets";
MyCodec["L_PAYMENTREQUEST_1_AMT0"] = ”1348.53";
MyCodec["L_PAYMENTREQUEST_1_QTY0"] = “1”;
MyCodec["PAYMENTREQUEST_1_ITEMAMT"] = ”1348.53";
MyCodec["PAYMENTREQUEST_1_AMT"] = ”1348.53”;
/*Complete API call*/
}
catch
{/*deal with exceptions*/}
}

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15. protected void DoSetEC(object sender, EventArgs e)
{
try
{
caller = new NVPCallerServices();
setProfile(MyProfile, “APIUsername”,”APIPassword”,”APISignature”);
MyCodec["METHOD"] = "SetExpressCheckout";
MyCodec["VERSION"] = “82“;
MyCodec["CANCELURL"] = ”MyCancelURL";
MyCodec["RETURNURL"] = ”MyReturnURL”;
MyCodec["PAYMENTREQUEST_0_CURRENCYCODE"] = ”GBP";
MyCodec["PAYMENTREQUEST_0_PAYMENTACTION"] = "Sale";
MyCodec["PAYMENTREQUEST_0_ITEMAMT"] = ”23.35";
MyCodec["PAYMENTREQUEST_0_AMT"] = ”23.35”
MyCodec["L_BILLINGTYPE0"] = "MerchantInitiatedBilling”;
MyCodec["L_PAYMENTTYPE0"] = "InstantOnly";
MyCodec["L_BILLINGAGREEMENTDESCRIPTION0"] = ”Car Insurance";
MyCodec["L_BILLINGAGREEMENTCUSTOM0"] = "MyTest";
/*Complete API call*/
} catch {/*deal with exceptions*/}
}
protected void StartReferenceTxn(string transactionID)
{
caller = new NVPCallerServices();
setProfile(MyProfile);
MyCodec["METHOD"] = "DoReferenceTransaction";
MyCodec["REFERENCEID"] = transactionID;
MyCodec["PAYMENTACTION"] = "Sale”;
MyCodec["AMT"] = ”39.95”;
MyCodec["CURRENCYCODE"] = "GBP”;
MyCodec["SOFTDESCRIPTOR"] = ”Car Insurance Installment”;
/*Complete API call*/
} catch {/*deal with exceptions*/}
}

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25. <script>
var dg = new PAYPAL.apps.DGFlow({
trigger: "submitBtn”
});
</script>
https://www.sandbox.paypal.com/incontext?token=<token>
<script>
top.dg.closeFlow();
</script>

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