feat: add DownloadCompleted event.

Author: zdpcdt

src/Client.Avalonia/Services/IDownloadService.cs

@@ -8,6 +8,7 @@ public interface IDownloadService
 {
     event Action<DownloadStatistics> ProgressChanged;
     event Action<DownloadStatus> StatusChanged;
+    event Action DownloadCompleted;
 
     DownloadStatistics CurrentStatistics { get; }
     DownloadStatus Status { get; }

src/Client.Avalonia/Services/MockDownloadService.cs

@@ -8,6 +8,7 @@ public class MockDownloadService : IDownloadService
 {
     public event Action<DownloadStatistics>? ProgressChanged;
     public event Action<DownloadStatus>? StatusChanged;
+    public event Action? DownloadCompleted;
 
     private readonly DispatcherTimer _timer;
     private readonly Random _random;
@@ -93,6 +94,7 @@ private void UpdateProgress(object? sender, EventArgs e)
         {
             _timer.Stop();
             UpdateStatus(DownloadStatus.Completed);
+            DownloadCompleted?.Invoke();
         }
     }
 

src/Client.Avalonia/ViewModels/MainViewViewModel.cs

@@ -26,7 +26,7 @@ public MainViewViewModel(IDownloadService downloadService)
 
         _downloadService.ProgressChanged += stats => Statistics = stats;
         _downloadService.StatusChanged += status => Status = status;
-        _downloadService.StatusChanged += OnDownloadCompleted;
+        _downloadService.DownloadCompleted += OnDownloadCompleted;
 
         Statistics = _downloadService.CurrentStatistics;
         Status = _downloadService.Status;
@@ -49,9 +49,8 @@ public MainViewViewModel(IDownloadService downloadService)
 
     #endregion
 
-    private void OnDownloadCompleted(DownloadStatus status)
+    private void OnDownloadCompleted()
     {
-        if (status is not DownloadStatus.Completed) return;
         _notificationManager.Show(new Notification(
             "更新完成",
             $"已更新到最新版本，版本号：{Statistics.Version}",