How can I decode the inputs to a transaction written by a smart contract constructor with Nethereum?

Question

I've been able to decode the inputs to a contract function transaction given the ABI as follows:

var myFunction = contract.GetFunction("MyFunction");
var myFunctionTxn = await contract.Eth.Transactions.GetTransactionByHash
        .SendRequestAsync(myTxnHash);
var inputs = myFunction.DecodeInput(myFunctionTxn.Input);

However, now I would like to do the same (i.e. retrieve a transaction hash and then decode the constructor inputs) for the constructor itself. I've looked at the ContractABI.Functions - I can see both the Constructor and the Functions, but the types are not compatable.

Also, I can see the types of the inputs from this, but unfortunately not the values:

var ctor = contract.ContractBuilder.ContractABI.Constructor;

Is there an equivalent for DecodeInput for constructors?

From here, it looks like this must be possible

StuartLC · Answer

Based on a brief conversation on Gitter with Nethereum's Juan Blanco, I'm using the code from the ConstructorCallDecoder to decode the Constructor.

using Nethereum.Web3;
...
var contract = _ethClient.Eth.GetContract(_contractAbi, contractAddress);
var ctorTransaction = await contract.Eth.Transactions.GetTransactionByHash
    .SendRequestAsync(constructorTransactionHash);
var decodedCtor = new ConstructorCallDecoder()
    .DecodeConstructorParameters(
        pocoToPopulate, _contractByteCode, ctorTransaction.Input);

Where

_contractAbi is the ABI for the smart contract
contractAddress is the address of the contract instance
constructorTransactionHash is the transaction hash of the constructor
_contractByteCode is the byte code of the Smart Contract
pocoToPopulate is an instance of a class decorated with the necessary Parameter attributes to receive the decoded parameters.

There are likely simpler ways to do this in future (e.g. without the redundancy of requiring both ABI and ByteCode to do the decoding), but this is good enough for me right now.

How can I decode the inputs to a transaction written by a smart contract constructor with Nethereum?

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