In order to fill an order (partially or completely) or to cancel an order, you’ll be generating and submitting transactions. The ICheckout interface, implemented by Checkout, exposes a few helpful methods and events.

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Building Transactions to Interact with Orders

The following async requests will return a Step[] these are used to generate transactions that, when submitted, perform the desired action. 
Step[] steps = await <insert here your desired method>;
TransactionReturn result = await steps.SubmitAsTransactions(_wallet, _chain);
// or 
Transaction[] stepTransactions = steps.AsTransactionArray();
All of these methods can be awaited directly. You can also subscribe to the OnTransactionStepsReturn and OnTransactionStepsError events to handle the responses elsewhere.
  1. GenerateBuyTransaction is used to buy a specified amount of a given collectible in the provided Order[]/listings
ICheckout checkout = new Checkout(_wallet, _chain);
Step[] steps = await checkout.GenerateBuyTransaction(listings, 5);
  1. GenerateSellTransaction is used to sell a specified amount for a given collectible in the provided Order[]/offers
ICheckout checkout = new Checkout(_wallet, _chain);
Step[] steps = await checkout.GenerateSellTransaction(offers, 3);
  1. GenerateListingTransaction is used to create a new listing for a given collectible, amount, and price.
ICheckout checkout = new Checkout(_wallet, _chain);
Step[] steps = await checkout.GenerateListingTransaction(collectionContractAddress, tokenId, 17, ContractType.ERC1155, currencyTokenAddress, 1000, expiryDateTime);
  1. GenerateOfferTransaction is used to create a new offer for a given collectible, amount, and price.
ICheckout checkout = new Checkout(_wallet, _chain);
Step[] steps = await checkout.GenerateOfferTransaction(collectionContractAddress, tokenId, 46, ContractType.ERC1155, currencyTokenAddress, 850, expiryDateTime);
  1. GenerateCancelTransaction is used to cancel an existing order created by the user.
ICheckout checkout = new Checkout(_wallet, _chain);
Step[] steps = await checkout.GenerateCancelTransaction(collectionContractAddress, order);
// Or alternatively provide the order id 
Step[] steps = await checkout.GenerateCancelTransaction(collectionContractAddress, orderIdString);