Question

我想将三个额外的参数传递给事件：

geocodeService.GeocodeCompleted += new EventHandler<GeocodeService.GeocodeCompletedEventArgs>(geocodeService_GeocodeCompleted);

参数是

int id
string color

double heading

private void Geocode(string strAddress, int waypointIndex, int id, string color, double heading)
{


    // Create the service variable and set the callback method using the GeocodeCompleted property.
    GeocodeService.GeocodeServiceClient geocodeService = new GeocodeService.GeocodeServiceClient("BasicHttpBinding_IGeocodeService");

    // NEED TO PASS id, color, heading TO THIS EVENT HANDLER
    geocodeService.GeocodeCompleted += new EventHandler<GeocodeService.GeocodeCompletedEventArgs>(geocodeService_GeocodeCompleted);

    GeocodeService.GeocodeRequest geocodeRequest = new GeocodeService.GeocodeRequest();
    geocodeRequest.Credentials = new Credentials();
    geocodeRequest.Credentials.ApplicationId = ((ApplicationIdCredentialsProvider)BingMap.CredentialsProvider).ApplicationId;
    geocodeRequest.Query = strAddress;
    geocodeService.GeocodeAsync(geocodeRequest, waypointIndex);
}


private void geocodeService_GeocodeCompleted(object sender, GeocodeService.GeocodeCompletedEventArgs e)
{
    GeocodeResult result = null;

    if (e.Result.Results.Count > 0)
    {
        result = e.Result.Results[0];
        if (result != null)
        {
            // this.ShowMarker(result);
            this.ShowShip(result);


        }
    }

}

Answer 1

您可以扩展GeocodeService.GeocodeServiceClient添加这些属性，然后在事件方法geocodeService_GeocodeCompleted中使用sender参数：

var service = (GeocodeService.GeocodeServiceClient) sender;

快速和脏（IMHO）版本是使用lambda表达式：

Pass parameter to EventHandler

Answer 2

看起来GeocodeCompletedEventArgs延伸AsyncCompletedEventArgs。 AsyncCompletedEventArgs具有属性UserState，可用于存储异步事件的状态信息。此状态通常作为参数传递给引发事件的方法。

有关详细信息，请参阅此问题：Bing GeocodeService userState usage as custom additional parameter

C＃将额外参数传递给事件

2 个答案: