> ## Documentation Index
> Fetch the complete documentation index at: https://docs.resq.software/llms.txt
> Use this file to discover all available pages before exploring further.

# ResQ.Blockchain.INeoClient.RecordEvidenceAsync(ResQ.Blockchain.EvidenceRecord,System.Threading.CancellationToken)

### [ResQ.Blockchain](./ResQ.Blockchain.md "ResQ.Blockchain").[INeoClient](./ResQ.Blockchain.INeoClient.md "ResQ.Blockchain.INeoClient")

## INeoClient.RecordEvidenceAsync(EvidenceRecord, CancellationToken) Method

Records evidence metadata on the blockchain with a reference to IPFS storage.

```csharp theme={null}
System.Threading.Tasks.Task<ResQ.Blockchain.TransactionResult> RecordEvidenceAsync(ResQ.Blockchain.EvidenceRecord evidence, System.Threading.CancellationToken cancellationToken=default(System.Threading.CancellationToken));
```

#### Parameters

<a name="ResQ.Blockchain.INeoClient.RecordEvidenceAsync(ResQ.Blockchain.EvidenceRecord,System.Threading.CancellationToken).evidence" />

`evidence` [EvidenceRecord](./ResQ.Blockchain.EvidenceRecord.md "ResQ.Blockchain.EvidenceRecord")

The evidence record containing IPFS CID and metadata.

<a name="ResQ.Blockchain.INeoClient.RecordEvidenceAsync(ResQ.Blockchain.EvidenceRecord,System.Threading.CancellationToken).cancellationToken" />

`cancellationToken` [System.Threading.CancellationToken](https://learn.microsoft.com/en-us/dotnet/api/system.threading.cancellationtoken "System.Threading.CancellationToken")

Cancellation token for the operation.

#### Returns

[System.Threading.Tasks.Task\<](https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task-1 "System.Threading.Tasks.Task`1")[TransactionResult](./ResQ.Blockchain.TransactionResult.md "ResQ.Blockchain.TransactionResult")[>](https://learn.microsoft.com/en-us/dotnet/api/system.threading.tasks.task-1 "System.Threading.Tasks.Task`1")\
A [TransactionResult](./ResQ.Blockchain.TransactionResult.md "ResQ.Blockchain.TransactionResult") containing the transaction hash and confirmation status.

#### Exceptions

[System.InvalidOperationException](https://learn.microsoft.com/en-us/dotnet/api/system.invalidoperationexception "System.InvalidOperationException")\
Thrown when the blockchain operation fails.

[System.OperationCanceledException](https://learn.microsoft.com/en-us/dotnet/api/system.operationcanceledexception "System.OperationCanceledException")\
Thrown when the operation is cancelled.

### Example

```csharp theme={null}
var evidence = new EvidenceRecord(
    IncidentId: "inc-001",
    IpfsCid: "Qmabc123...",
    ContentType: "image/jpeg",
    SizeBytes: 1024567,
    Hash: "sha256:..."
);

var result = await neoClient.RecordEvidenceAsync(evidence);
Console.WriteLine($"Evidence recorded: {result.TransactionHash}");
```

### Remarks

Evidence is stored on IPFS for decentralized storage, while the blockchain records
a permanent, immutable reference to the evidence along with its hash for integrity verification.