参考下面的屏幕截图,我有以下视图和viewmodel设置来表示进度条下载。当我向这个下载集合添加超过1个下载时,似乎下载1将覆盖下载2的Progress()公共属性。
下面的示例是下载1下载1MB它将首先完成并与下载2下载5MB进行比较。 当下载1完成后,下载2(下面的hello2示例)进度条就在那里停止但是仍然在后台下载字节,直到达到5MB。
如何更改代码以确保下载1不会干扰下载2的进度条UI。我已经尝试将Progress()修改为私有,但之后两个进度条UI都没有显示
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<ItemsControl Name="MyItemsControl" ItemsSource="{Binding GameDownloads}">
<ItemsControl.ItemTemplate>
<DataTemplate>
<Grid DockPanel.Dock="Right">
<Grid.RowDefinitions>
<RowDefinition />
<RowDefinition />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="200" />
<ColumnDefinition />
</Grid.ColumnDefinitions>
<TextBlock Grid.Row="0" Grid.Column="0" Text="{Binding GameName}" />
<ProgressBar Grid.Row="0" Grid.Column="1" Minimum="0" Maximum="100" Value="{Binding Progress, Mode=OneWay}" />
<TextBlock Grid.Row="1" Grid.Column="1" Text="{Binding StatusText}" />
</Grid>
</DataTemplate>
</ItemsControl.ItemTemplate>
</ItemsControl>
DownloadAppViewModel
Public Class DownloadAppViewModel
Inherits ViewModelBase
Private ReadOnly WC As WebClient
Public Sub New(ByVal Name As String, ByVal URL As String, ByVal FileName As String)
_gameName = Name
WC = New WebClient
AddHandler WC.DownloadFileCompleted, AddressOf DownloadCompleted
AddHandler WC.DownloadProgressChanged, AddressOf DownloadProgressChanged
WC.DownloadFileAsync(New Uri(URL), FileName)
End Sub
Private Sub DownloadCompleted(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs)
End Sub
Private Sub DownloadProgressChanged(ByVal sender As [Object], ByVal e As DownloadProgressChangedEventArgs)
If _totalSize = 0 Then
_totalSize = e.TotalBytesToReceive
End If
DownloadedSize = e.BytesReceived
End Sub
Private _gameName As String
Public Property GameName() As String
Get
Return _gameName
End Get
Set(ByVal value As String)
_gameName = value
Me.OnPropertyChanged("GameName")
End Set
End Property
Public ReadOnly Property StatusText() As String
Get
If _downloadedSize < _totalSize Then
Return String.Format("Downloading {0} MB of {1} MB", _downloadedSize, _totalSize)
End If
Return "Download completed"
End Get
End Property
Private _totalSize As Long
Private Property TotalSize() As Long
Get
Return _totalSize
End Get
Set(ByVal value As Long)
_totalSize = value
OnPropertyChanged("TotalSize")
OnPropertyChanged("Progress")
OnPropertyChanged("StatusText")
End Set
End Property
Private _downloadedSize As Long
Private Property DownloadedSize() As Long
Get
Return _downloadedSize
End Get
Set(ByVal value As Long)
_downloadedSize = value
OnPropertyChanged("DownloadedSize")
OnPropertyChanged("Progress")
OnPropertyChanged("StatusText")
End Set
End Property
Public ReadOnly Property Progress() As Double
Get
If _totalSize <> 0 Then
Return 100.0 * _downloadedSize / _totalSize
Else
Return 0.0
End If
End Get
End Property
End Class