Indexed string in event cannot be parsed

[greenkiller]

Hi,

I deployed a straight forward smart contract as below and used GetAllChanges to get all events from block 0. GetAllChanges functions throws overflow exception when I tried to get the MultipliedLog event :
Value was either too large or too small for an Int32

My testing shows that it happens when I put a "indexed" keyword after a string. Is it expected?
event Multiplied(uint indexed a, uint indexed result, string hello);
event MultipliedLog(uint indexed a, address indexed sender, string indexed hello);

[juanfranblanco]

Thanks for the clarification... can you post your Event DTO?

[juanfranblanco]

Also please raise another issue if it is changed :) (obviously not now)

[greenkiller]

Hi Juan,

Here is the DTO for them. Thanks.

public class EventMultipliedSenderLog
{
    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("uint", "a", 1, true)]
    public int A { get; set; }

    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("address", "sender", 2, true)]
    public string Sender { get; set; }

    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("string", "hello", 3, true)]
    public string Hello { get; set; }
}

public class EventMultiplied
{
    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("uint", "a", 1, true)]
    public int A { get; set; }

    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("uint", "result", 2, true)]
    public int Result { get; set; }

    [Nethereum.ABI.FunctionEncoding.Attributes.Parameter("string", "hello", 3, false)]
    public string Hello { get; set; }
}

[greenkiller]

The C# code to get the events:

            var multipliedEvent = contract.GetEvent("MultipliedLog");
            var filterAll = await multipliedEvent.CreateFilterAsync(new Nethereum.RPC.Eth.DTOs.BlockParameter(0));
            var eventLogsAll = await multipliedEvent.GetAllChanges<EventMultiplied2>(filterAll);

Event Multiplied (with DTO EventMultiplied) works well. The only difference I can find is the "indexed" string.

[juanfranblanco]

Short story, retrieving the indexed values for dynamic types (strings, arrays) is not supported.
Long story:
The topics for indexed types if dynamics are stored as the SHA3 Keccak value (so they can be indexed and searched by matching the value).
Work around:
Use a bytes32, or don't index strings if you just want the data

[juanfranblanco]

So for example if you look at the index topic for "Hello world" it retrieves ed6c11b0b5b808960df26f5bfc471d04c1995b0ffd2055925ad1be28d6baadfd

[juanfranblanco]

Keeping it open as I need to validate the data part

[greenkiller]

I see. Thanks.

[juanfranblanco]

I have just pushed a fix which will allow to have indexed dynamic types as part of the Event DTO, mainly they will store the sha3 keccak string. This will prevent an error to be thrown, when decoding.

A further solution for your problem if you want to have the index and value of the string will be to have 2 event parameters, 1 for the index and another for the value.

[greenkiller]

Thanks for the prompt solution Juan!