​
Subscribe to Custom Events

Use the SubscribeEvents call to listen for custom or existing events from any contract. Make sure that the event string matches the event signature in Solidity and define the contract address that you want to listen to. You can define additional filters to only receive events from specific wallets or token Ids. The OnEventReceived function provides a SubscribeEventsReturn object that includes any information such as contract type, transaction hash and more. When you want to retrieve the emitted event values, use EventDecoded object at SubscribeEventsReturn > EventLog > EventDecoded. 
var indexer = new ChainIndexer(Chain.TestnetArbitrumSepolia);
var streamOptions = new WebRPCStreamOptions<SubscribeEventsReturn>(
    OnEventReceived,
    OnWebRPCErrorReceived);

var eventFilter = new EventFilter
{
    accounts = Array.Empty<string>(),
    contractAddresses = new[] {"0x4ab3b16e9d3328f6d8025e71cefc64305ae4fe9c"},
    tokenIDs = new[] {"0"},
    events = new[] {"Transfer(address indexed from, address indexed to, uint256 value)"}
};

indexer.SubscribeEvents(new SubscribeEventsArgs(eventFilter), streamOptions);

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Subscribe to Balance Updates

Listen to balance updates for wallets on a specified contract. The OnBalanceUpdateReceived function provides a SubscribeBalanceUpdatesReturn object that includes the current balance of the wallet address you specified. 
var indexer = new ChainIndexer(Chain.TestnetArbitrumSepolia);
var streamOptions = new WebRPCStreamOptions<SubscribeBalanceUpdatesReturn>(
    OnBalanceUpdateReceived,
    OnWebRPCErrorReceived);

var contractAddress = "0x4ab3b16e9d3328f6d8025e71cefc64305ae4fe9c";
indexer.SubscribeBalanceUpdates(new SubscribeBalanceUpdatesArgs(contractAddress), streamOptions);

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Subscribe to Receipts

Listen to receipt updates on a specified contract. The OnSubscribeReceiptsMessageReceived function provides a SubscribeReceiptsReturn object that includes the current receipt information. 
var indexer = new ChainIndexer(Chain.TestnetArbitrumSepolia);
var streamOptions = new WebRPCStreamOptions<SubscribeReceiptsReturn>(
    OnSubscribeReceiptsMessageReceived,
    OnWebRPCErrorReceived);

var filter = new TransactionFilter
{
    contractAddress = "0x4ab3b16e9d3328f6d8025e71cefc64305ae4fe9c"
};

indexer.SubscribeReceipts(new SubscribeReceiptsArgs(filter), streamOptions);

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Abort Streams

Make sure to cancel streams when you don’t want to receive events anymore. This will abort all running listeners in your game. 
new ChainIndexer(Chain.TestnetArbitrumSepolia).AbortStreams();