VB.Net缺乏隐式接口是否使我想做的事情变得不可能？
我知道VB.Net不允许像C＃这样的隐式接口实现。 因此，如下代码没有直接的VB.Net相关性：
public interface IBackgroundWorkerAdapter { bool IsBusy { get; set; } bool WorkerReportsProgress { get; set; } bool WorkerSupportsCancellation { get; set; } event DoWorkEventHandler DoWork; event ProgressChangedEventHandler ProgressChanged; event RunWorkerCompletedEventHandler RunWorkerCompleted; void RunWorkerAsync(); void CancelAsync(); void ReportProgress(int progressPercent); void ReportProgress(int progressPercent, object userState); } public class BackgroundWorkerAdapter: BackgroundWorker, IBackgroundWorkerAdapter { } 因此，我在VB.Net中可以想到的最接近的想法是使用Shadows关键字执行以下操作（因为没有任何操作是虚拟的）：
Public Class BackgroundWorkerAdapter Inherits BackgroundWorker Implements IBackgroundWorkerAdapter Public Shadows ReadOnly Property IsBusy As Boolean _ Implements IBackgroundWorkerAdapter.IsBusy Get Return MyBase.IsBusy End Get End Property Public Shadows Property WorkerReportsProgress As Boolean _ Implements IBackgroundWorkerAdapter.WorkerReportsProgress Get Return MyBase.WorkerReportsProgress End Get Set(ByVal value As Boolean) MyBase.WorkerReportsProgress = value End Set End Property Public Shadows Property WorkerSupportsCancellation As Boolean _ Implements IBackgroundWorkerAdapter.WorkerSupportsCancellation Get Return MyBase.WorkerSupportsCancellation End Get Set(ByVal value As Boolean) MyBase.WorkerSupportsCancellation = value End Set End Property Public Shadows Event DoWork( ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) _ Implements IBackgroundWorkerAdapter.DoWork Public Shadows Event ProgressChanged( ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) _ Implements IBackgroundWorkerAdapter.ProgressChanged Public Shadows Event RunWorkerCompleted( ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) _ Implements IBackgroundWorkerAdapter.RunWorkerCompleted Public Sub New() MyBase.New() End Sub Public Shadows Sub CancelAsync() _ Implements IBackgroundWorkerAdapter.CancelAsync MyBase.CancelAsync() End Sub Public Shadows Sub ReportProgress(ByVal progressPercent As Integer) _ Implements IBackgroundWorkerAdapter.ReportProgress MyBase.ReportProgress(progressPercent) End Sub Public Shadows Sub ReportProgress( ByVal progressPercent As Integer, ByVal userState As Object) _ Implements IBackgroundWorkerAdapter.ReportProgress MyBase.ReportProgress(progressPercent, userState) End Sub Public Shadows Sub RunWorkerAsync() _ Implements IBackgroundWorkerAdapter.RunWorkerAsync MyBase.RunWorkerAsync() End Sub End Class
然后我尝试使用包装器如下：
Private ReadOnly _Worker As IBackgroundWorkerAdapter Public ReadOnly Property Worker() As IBackgroundWorkerAdapter Get Return _Worker End Get End Property ... AddHandler Me.Worker.DoWork, Sub() ... End Sub AddHandler Me.Worker.ProgressChanged, Sub(sender, e) Dim args = DirectCast(e, ProgressChangedEventArgs) ... End Sub AddHandler Me.Worker.RunWorkerCompleted, Sub() ... End Sub Me.Worker.RunWorkerAsync()
然而，当然这不起作用（事件处理程序没有执行），可能是因为我正在调用RunWorkerAsync和ReportProgress方法的基类，并且基类没有使用Shadowed事件。 因此，有没有办法实现相同的最终结果，其中BackgroundWorker实现类似于C＃的接口，而是使用VB.Net的显式接口实现？
完整解决方案更新（使用Damien_The_Unbeliever的答案）
Imports System.ComponentModel Public Class BackgroundWorkerAdapter Inherits BackgroundWorker Implements IBackgroundWorkerAdapter Public Shadows ReadOnly Property IsBusy As Boolean _ Implements IBackgroundWorkerAdapter.IsBusy Get Return MyBase.IsBusy End Get End Property Public Shadows Property WorkerReportsProgress As Boolean _ Implements IBackgroundWorkerAdapter.WorkerReportsProgress Get Return MyBase.WorkerReportsProgress End Get Set(ByVal value As Boolean) MyBase.WorkerReportsProgress = value End Set End Property Public Shadows Property WorkerSupportsCancellation As Boolean _ Implements IBackgroundWorkerAdapter.WorkerSupportsCancellation Get Return MyBase.WorkerSupportsCancellation End Get Set(ByVal value As Boolean) MyBase.WorkerSupportsCancellation = value End Set End Property Public Shadows Custom Event DoWork As DoWorkEventHandler _ Implements IBackgroundWorkerAdapter.DoWork AddHandler(ByVal value As DoWorkEventHandler) AddHandler MyBase.DoWork, value End AddHandler RemoveHandler(ByVal value As DoWorkEventHandler) RemoveHandler MyBase.DoWork, value End RemoveHandler RaiseEvent(ByVal sender As Object, ByVal e As System.ComponentModel.DoWorkEventArgs) MyBase.OnDoWork(e) End RaiseEvent End Event Public Shadows Custom Event ProgressChanged As ProgressChangedEventHandler _ Implements IBackgroundWorkerAdapter.ProgressChanged AddHandler(ByVal value As ProgressChangedEventHandler) AddHandler MyBase.ProgressChanged, value End AddHandler RemoveHandler(ByVal value As ProgressChangedEventHandler) RemoveHandler MyBase.ProgressChanged, value End RemoveHandler RaiseEvent(ByVal sender As Object, ByVal e As System.ComponentModel.ProgressChangedEventArgs) MyBase.OnProgressChanged(e) End RaiseEvent End Event Public Shadows Custom Event RunWorkerCompleted As RunWorkerCompletedEventHandler _ Implements IBackgroundWorkerAdapter.RunWorkerCompleted AddHandler(ByVal value As RunWorkerCompletedEventHandler) AddHandler MyBase.RunWorkerCompleted, value End AddHandler RemoveHandler(ByVal value As RunWorkerCompletedEventHandler) RemoveHandler MyBase.RunWorkerCompleted, value End RemoveHandler RaiseEvent(ByVal sender As Object, ByVal e As System.ComponentModel.RunWorkerCompletedEventArgs) MyBase.OnRunWorkerCompleted(e) End RaiseEvent End Event Public Sub New() MyBase.New() End Sub Public Shadows Sub CancelAsync() _ Implements IBackgroundWorkerAdapter.CancelAsync MyBase.CancelAsync() End Sub Public Shadows Sub ReportProgress(ByVal progressPercent As Integer) _ Implements IBackgroundWorkerAdapter.ReportProgress MyBase.ReportProgress(progressPercent) End Sub Public Shadows Sub ReportProgress( ByVal progressPercent As Integer, ByVal userState As Object) _ Implements IBackgroundWorkerAdapter.ReportProgress MyBase.ReportProgress(progressPercent, userState) End Sub Public Shadows Sub RunWorkerAsync() _ Implements IBackgroundWorkerAdapter.RunWorkerAsync MyBase.RunWorkerAsync() End Sub End Class
我认为，就像你已经展示的潜艇一样，你需要将所有的呼叫传递给基类中的相同调用。 最棘手的是事件处理程序，但DoWork可以实现为：
Public Shadows Custom Event DoWork As DoWorkEventHandler Implements IBackgroundWorkerAdapter.DoWork AddHandler(Value As DoWorkEventHandler) AddHandler MyBase.DoWork, Value End AddHandler RemoveHandler(Value As DoWorkEventHandler) RemoveHandler MyBase.DoWork, Value End RemoveHandler RaiseEvent(sender As Object, e As DoWorkEventArgs) MyBase.OnDoWork(e) End RaiseEvent End Event
对于其他事件处理程序也是如此。 通过这种方式，通过DoWork事件添加的事件处理程序实际上已添加到基类DoWork事件中。