wpf - UI更新不快

Question

晚上好

以下是我用来从驱动器等读取文件和文件夹的代码。

Public Class LoadingBox

    Public counter As ULong
    Public OpenRecords As New Dictionary(Of String, MainWindow.records)
    Public Path As String
    Public Diskname As String
    Private WithEvents BKWorker As New BackgroundWorker()


    Public Sub New(ByVal _Path As String, ByVal _Diskname As String)

        ' This call is required by the designer.
        InitializeComponent()

        ' Add any initialization after the InitializeComponent() call.
        Path = _path
        Diskname = _diskname
    End Sub

    Private Sub GetStructure(ByVal tempdir As String, ByVal ParentID As String, ByVal DiskName As String)
        Dim maindir As DirectoryInfo = My.Computer.FileSystem.GetDirectoryInfo(tempdir)
        For Each Dir As DirectoryInfo In maindir.GetDirectories
            Try
                Dim d As New MainWindow.records
                d.Filename = Dir.Name
                d.Folder = True
                d.Rowid = Date.UtcNow.ToString() + counter.ToString()
                d.Size = 0
                d.ParentID = ParentID
                d.DiskName = DiskName
                d.DateCreated = Dir.CreationTimeUtc
                d.DateModified = Dir.LastWriteTimeUtc
                OpenRecords.Add(d.Rowid, d)
                'Label1.Content = "Processing: " + Dir.FullName
                BKWorker.ReportProgress(0, Dir.FullName)
                counter = counter + 1
                GetStructure(Dir.FullName, d.Rowid, DiskName)
            Catch ex As Exception

            End Try


        Next
        For Each fil As FileInfo In maindir.GetFiles
            Try
                Dim d As New MainWindow.records
                d.Filename = fil.Name
                d.Folder = False
                d.Rowid = Date.UtcNow.ToString() + counter.ToString()
                d.Size = fil.Length
                d.ParentID = ParentID
                d.DiskName = DiskName
                d.DateCreated = fil.CreationTimeUtc
                d.DateModified = fil.LastWriteTimeUtc
                OpenRecords.Add(d.Rowid, d)
                'Label1.Content = "Processing: " + fil.FullName
                BKWorker.ReportProgress(0, fil.FullName)
                counter = counter + 1
            Catch ex As Exception

            End Try

        Next
    End Sub

    Private Sub Window_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        counter = 0
        BKWorker.WorkerReportsProgress = True
        AddHandler BKWorker.DoWork, AddressOf BKWorker_Do
        AddHandler BKWorker.ProgressChanged, AddressOf BKWorker_Progress
        AddHandler BKWorker.RunWorkerCompleted, AddressOf BKWorker_Completed
        BKWorker.RunWorkerAsync()

        'GetStructure(Path, "0", Diskname)
    End Sub

    Private Sub BKWorker_Do(ByVal sender As Object, ByVal e As DoWorkEventArgs)
        'Throw New NotImplementedException
        GetStructure(Path, "0", Diskname)
    End Sub

    Private Sub BKWorker_Progress(ByVal sender As Object, ByVal e As ProgressChangedEventArgs)
        'Throw New NotImplementedException
        Label1.Content = "Processing: " + e.UserState.ToString()
        If ProgressBar1.Value = 100 Then
            ProgressBar1.Value = 0
        End If
        ProgressBar1.Value = ProgressBar1.Value + 1
    End Sub

    Private Sub BKWorker_Completed(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
        'Throw New NotImplementedException
        MessageBox.Show("Completed")
        Me.Close()
    End Sub
End Class

但问题是，后台线程能够非常快地读取文件，但 UI 线程无法跟上它的速度，请问我如何解决这个问题。

Answer 1

当您迭代那么多项目时，您几乎不想报告每个项目的进度。

我建议在报告进度之前找到一些合理数量的文件等待。每 5 次或每 10 次左右。您可能想看看您的正常文件数是多少。换句话说，如果您通常只处理 25 个文件，您可能不想每 10 个文件更新一次。但是，如果您通常处理 25000 个文件，您甚至可以每 100 个文件更新一次。