Use Smart contracts mint function in nethereum with parameters

Question

I try to build a game in unity, in which you can earn a blockchain token by minting it.

The API of the mint function looks like this:

{
  "constant": false,
  "inputs": [{"internalType": "address","name": "account","type": "address"},   {"internalType": "uint256","name": "amount","type": "uint256"}],
  "name": "mint",
  "outputs": [{"internalType": "bool","name": "","type": "bool"}],
  "payable": false,
  "stateMutability": "nonpayable",
  "type": "function"
}

I first checked the approach in the flappy-bird-documentation and tried to change the set to score as follows:

public Function mintToken() {
    return contract.GetFunction("mint");
}

CreateMintTokenTransactionInput(string addressFrom, string addressOwner, string privateKey, string adress , BigInteger amount, HexBigInteger gas = null, HexBigInteger valueAmount = null) {
  var function = mintToken ();
  return function.CreateTransactionInput(addressFrom, gas, valueAmount, adress, amount);
}

In the Start method of unity I go:

var transactionInput = CreateMintTokenTransactionInput(_userAddress, _addressOwner, _privateKey, adress, amount);

var transactionSignedRequest = new TransactionSignedUnityRequest(_url, GameControl.instance.Key, _userAddress);

//send and wait
yield return transactionSignedRequest.SignAndSendTransaction(transactionInput);

But the parameters of the function seem to be wrong.

I wonder if there is an easier way to do this or how I could fix my approach. In more general terms: How can I call an arbitrary smart contract method with parameters in Ethereum?

The next Problem ist that i dont get a transactionHash and I am not sure how to Debug this:

yield return transactionMintRequest.SignAndSendTransaction(mint, contractAddress);
    if (transactionMintRequest.Exception != null)
        {
            Debug.Log(transactionMintRequest.Exception.Message);
            yield break;
        }
        Debug.Log(transactionMintRequest);
        var transactionMintHash = transactionMintRequest.Result;        
        Debug.Log("Transfer txn hash:" + transactionMintHash);

score 1 · Accepted Answer · edited Jun 07 '22 at 19:03

Following the documentation http://docs.nethereum.com/en/latest/unity3d-smartcontracts-getting-started/#transfer-transaction

The simplest thing to do is to create first your Mint Function, this has been code generated using the http://playground.nethereum.com/

public partial class MintFunction : MintFunctionBase { }

[Function("mint", "bool")]
public class MintFunctionBase : FunctionMessage
{
    [Parameter("address", "account", 1)]
    public virtual string Account { get; set; }
    [Parameter("uint256", "amount", 2)]
    public virtual BigInteger Amount { get; set; }
}

Then create your TransactionSignedUnityRequest as follows:

 var transactionMintRequest = new TransactionSignedUnityRequest(url, privateKey, "YOURCHAINID");
        
 var mint = new MintFunction
 {
   Account= account,
   Amount = amount,
 };

        yield return transactionMintRequest.SignAndSendTransaction(mint, contractAddress);
        var transactionMintHash = transactionMintRequest.Result;

Thank you very much for responding to such a beginner question so fast. Even if the Dokumentation is really great sometimes its hard for a beginner. I hope that others will also find it usefull. I guess it should be var mint = new MintFunction? — user3762507, Jun 05 '22 at 15:59
I seems you have to add the following line to make it working in unity transactionMintRequest.UseLegacyAsDefault = true. Now it works for me. — user3762507, Jun 06 '22 at 16:51

Use Smart contracts mint function in nethereum with parameters

1 Answers1