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做一些有趣的项目可以帮助我学习。这是我正在做的一个项目，我已经学到了很多东西。我希望看到该程序的 CPU 密集度较低。有人对我如何做到这一点有任何建议吗？

基本上这个程序只是将一些雪花覆盖在电脑屏幕上。

编辑：

我目前正在研究的是看我是否可以使用 DoubleAnimationUsingPath 并绑定到 PathGeometry。当我试图弄清楚这一点时，我欢迎有关此方法或任何其他方法的任何建议或提示。

WPF/XAML：

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    AllowsTransparency="True"
        WindowStyle="None"
    Title="MainWindow" Height="350" Width="525" Background="Transparent" Topmost="True" WindowState="Maximized" ResizeMode="NoResize">
    <Canvas Name="canvas1">

    </Canvas>
</Window>

VB.NET 主窗口：

Imports System.ComponentModel

Class MainWindow

    Dim bw As New BackgroundWorker
    Dim flakes(17) As flake

    Private Sub Window_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        For i = 0 To flakes.Count - 1
            flakes(i) = New flake
            flakes(i).image.DataContext = flakes(i)
            flakes(i).image.SetBinding(Canvas.LeftProperty, "left")
            flakes(i).image.SetBinding(Canvas.TopProperty, "top")
            canvas1.Children.Add(flakes(i).image)
        Next

        AddHandler bw.DoWork, AddressOf backgroundMover
        bw.RunWorkerAsync()
    End Sub


    Private Sub backgroundMover()
        While (True)
            For Each f In flakes
                f.move()
            Next
            System.Threading.Thread.Sleep(50)
        End While
    End Sub
End Class

VB.Net 薄片类：

Imports System.ComponentModel

Public Class flake
    Implements INotifyPropertyChanged

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Private Sub NotifyPropertyChanged(ByVal info As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
    End Sub

    Private Property startLeft As Double
    Private Property _left As Double
    Private Property _top As Double
    Private Property speed As Double
    Private Property amplitude As Double
    Private Property period As Double
    Public Property image As New Image
    Private Shared Property r As New Random

    Public Sub New()
        _image.Width = 28
        _image.Height = 26
        _image.Source = New System.Windows.Media.Imaging.BitmapImage(New Uri("/snowTest;component/Images/blue-pin-md.png", UriKind.Relative))
        startFresh()
    End Sub

    Public ReadOnly Property left As Double
        Get
            Return _left
        End Get
    End Property

    Public ReadOnly Property top As Double
        Get
            Return _top
        End Get
    End Property

    Public Sub startFresh()
        _top = -30
        amplitude = r.Next(5, 35)
        period = 1 / r.Next(20, 60)
        speed = r.Next(15, 25) / 10
        startLeft = r.Next(0, System.Windows.SystemParameters.PrimaryScreenWidth)
    End Sub

    Public Sub move()
        If _top > System.Windows.SystemParameters.PrimaryScreenHeight Then
            startFresh()
        Else
            _top += speed
            _left = amplitude * Math.Cos(period * _top) + startLeft
        End If

        NotifyPropertyChanged("top")
        NotifyPropertyChanged("left")
    End Sub
End Class
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1 回答 1

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在画布内更新 UIElement 上的 LeftProperty 和 TopProperty 会强制每次更新都进行新的布局传递。从性能的角度来看，WPF 中的布局非常昂贵。您应该改用UIElement.RenderTransform属性。

于 2012-12-05T14:09:05.223 回答