c# - 返回类型错误

Question

我不明白为什么会出现以下错误:

'System.Collections.Generic.List Notify.MainPage.webClient_OpenReadCompleted(object, System.Net.OpenReadCompletedEventArgs)' has the wrong return type

代码:

webClient.OpenReadCompleted += webClient_OpenReadCompleted;

和:

private List<SightingType> webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
        {
            DataContractJsonSerializer ser = null;
            var sightingT = new List<SightingType>();
            try
            {
                ser = new DataContractJsonSerializer(typeof(ObservableCollection<SightingType>));
                ObservableCollection<SightingType> sightingTypes = ser.ReadObject(e.Result) as ObservableCollection<SightingType>;
                foreach (var sightingType in sightingTypes)
                {
                    sightingT.Add(sightingType);
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

            return sightingT;
        }

有谁知道我哪里出错了？

Answer 1

事件处理程序的返回类型应为 void:

private void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
        {

另一端没有接收返回数据的东西。