如何连接ImageSource的绑定？
如何连接ImageSource的绑定？
提问于 2019-01-07 08:01:39
我正在尝试在我的WPF Window上包含一个县海豹的图像，并将源绑定到一个BitmapImage属性，但是图像根本不显示。我还想单击印章并使用LeftMouseButtonDown事件将第一个图像更改为其他七个图像，每次更改之间有两秒的延迟。
我在this StackOverflow post中尝试了这些技术。
MainWindow.xaml中的图像定义：
<Image x:Name="imag_CountySeal" Margin="0,60,0,80" Grid.Row="0"
Grid.Column="0"
Source="{Binding ImageSource, UpdateSourceTrigger=PropertyChanged,Mode=OneWay}"
MouseLeftButtonDown="Mouse_Down_Seal"
Width="165" Height="165" Visibility="Visible" />具有ImageSource属性和PropertyChanged事件的类定义：
public class CountySeals : INotifyPropertyChanged
{
private BitmapImage _ImageSource;
public BitmapImage ImageSource
{
get { return _ImageSource; }
set
{
_ImageSource = value;
OnPropertyChanged(new PropertyChangedEventArgs("ImageSource"));
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(PropertyChangedEventArgs e)
{
if (PropertyChanged != null)
{
PropertyChanged(this, e);
}
}
}MainWindow.xaml.cs开头的逻辑，用于为第一个镜像设置ImageSource：
public partial class MainWindow : Window
{
CountySeals seals;
public MainWindow()
{
InitializeComponent();
seals = new CountySeals();
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_l transparent.png", UriKind.Absolute));
SizeChanged += new SizeChangedEventHandler(Window_SizeChanged);
StateChanged += new EventHandler(Window_StateChanged);
LocationChanged += new EventHandler(Window_LocationChanged);MainWindow.xaml.cs中的Mouse_Down_Seal代码：
private void Mouse_Down_Seal(object sender, MouseButtonEventArgs e)
{
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_2 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_3 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_4 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_5 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_6 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_7 transparent.png", UriKind.Absolute));
Thread.Sleep(2000);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_8 transparent.png", UriKind.Absolute));
}如何连接ImageSource的Binding
回答 1
Stack Overflow用户
回答已采纳
发布于 2019-01-07 08:22:08
您需要将seals设置为您的MainWindow DataContext：
public MainWindow()
{
InitializeComponent();
seals = new CountySeals();
this.DataContext = seals; // <---------
... etc ...更新:位图不显示的问题是完全不同的问题。您的鼠标处理程序是在GUI线程上调用的，但是您随后使用Task.Sleep命令将该线程捆绑在一起，因此它永远没有机会更新图像。事实上，你会发现当这一切发生的时候，你的整个应用程序都会冻结。您需要在单独的thread...and中分配ImageSource并执行休眠等操作。在C#中，正确的方法是使用Tasks (除了非常非常少的例外，您永远不应该在C#中调用Thread.Sleep() )。您还需要添加代码来检查任务是否已经在运行，如果已经运行，则首先取消它。下面这样的代码应该能起到作用：
private Task DisplayTask;
private CancellationTokenSource CancelSource;
private void Image_MouseDown(object sender, MouseButtonEventArgs e)
{
// cancel any existing task and wait for it to finish
if (this.CancelSource != null)
{
this.CancelSource.Cancel();
try
{
this.DisplayTask.Wait(this.CancelSource.Token);
}
catch (OperationCanceledException)
{
// catches the expected exception here
}
}
// start a new task
this.CancelSource = new CancellationTokenSource();
this.DisplayTask = Task.Run(DisplayImages);
}
private async Task DisplayImages()
{
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_2 transparent.png", UriKind.Absolute));
await Task.Delay(TimeSpan.FromSeconds(2), this.CancelSource.Token);
seals.ImageSource = new BitmapImage(new Uri(@"C:\Users\billw\Documents\Visual Studio 2015\Projects\Images\seal_3 transparent.png", UriKind.Absolute));
await Task.Delay(TimeSpan.FromSeconds(2), this.CancelSource.Token);
... etc ...
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/54067072
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