> For the complete documentation index, see [llms.txt](https://developer.magtek.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.magtek.com/sdks-and-tools/universal-sdk-documentation/android/ieventsubscriber-delegates.md).

# IEventSubscriber Delegates

MTUSDKNET API will invoke the callback function in this chapter to provide the requested data and/or a detailed response. To delegate the event, call the subscribeAll function with the name of a class that implements the IEventSubscriber Delegates interface.

## OnEvent

OnEvent handles all event types. The `eventType` parameter defines which event is triggered.

```csharp
public void OnEvent( 
    EventType eventType, 
    IData data);
```

| Parameter   | Description                                                                  |
| ----------- | ---------------------------------------------------------------------------- |
| `eventType` | An enumeration indicating the event triggered by the device.                 |
| `data`      | Contains the data for the event. The payload is dependent on the event type. |

Return Value: None

**Example**

```csharp
public class OnEventClass implements IEventSubscriber
{
    public void OnEvent(EventType eventType, IData data)
    {
        // Event handler
    }

}

OnEventClass eventCallBack = new OnEventClass(); 
device.subscribeAll(evenCallBack);
```

In this example, the main window implements `IEventSubscriber`. The keyword `this` is used to pass in the name of the current class `MainWindow`.

```csharp
public partial class MainWindow implements IEventSubscriber
{
    public void OnEvent(EventType eventType, IData data)
    {
        // Event handler
    }
    
    public void connectDevice()
    {
        device.subscribeAll(this);
    }
}
```

## Event Data Parsing

Classes can be initialized by passing in the data byte array.

**Example**

```csharp
public void OnEvent(EventType eventType, IData data)
    {
        // Barcode data BarCodeData barcodeData =
BarCodeDataBuilder.GetBarCodeData(DeviceType.MMS, data.ByteArray());
 
    // Input request
    InputRequest ir = new InputRequest(data.ByteArray());
 
    // NFC data
    NFCData nfcData = NFCDataBuilder.GetNFCData(DeviceType.MMS, data.ByteArray());

    // Enhanced input request 
    EnhancedInputRequest eir = new
EnhancedInputRequest(data.ByteArray());
    List<DirectoryEntry> deList = eir.EnhancedSelectionList;
 
    }
```


---

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