C# 使用MVVM在WPF中相对于图像的鼠标位置
在wpf应用程序中,当鼠标位于图像上方时,我尝试在获取鼠标位置时遵循MVVM结构。鼠标位置应转换为相对于图像的像素位置 当Image_MouseMove位于ImagePositionView.xaml.cs中时,我就可以使用它了,但对于如何使用MVVM结构实现这一点,我有点不知所措(即使在尝试读取其他线程之后) 我添加了一个对MVVMLight的引用,希望这将使这项任务更容易,但我以前从未使用过 这就是我到目前为止所做的: 视图: 根据我所看到的,我添加了这些参考资料:C# 使用MVVM在WPF中相对于图像的鼠标位置,c#,wpf,xaml,mvvm,C#,Wpf,Xaml,Mvvm,在wpf应用程序中,当鼠标位于图像上方时,我尝试在获取鼠标位置时遵循MVVM结构。鼠标位置应转换为相对于图像的像素位置 当Image_MouseMove位于ImagePositionView.xaml.cs中时,我就可以使用它了,但对于如何使用MVVM结构实现这一点,我有点不知所措(即使在尝试读取其他线程之后) 我添加了一个对MVVMLight的引用,希望这将使这项任务更容易,但我以前从未使用过 这就是我到目前为止所做的: 视图: 根据我所看到的,我添加了这些参考资料: xmlns:i=”htt
xmlns:i=”http://schemas.microsoft.com/expression/2010/interactivity“
xmlns:cmd=”http://www.galasoft.ch/mvvmlight“
我想主要的问题是如何从
ImagePositionViewModel
中访问view元素ImageOnDisplay
,我是通过一种行为来实现的。首先,我声明我的视图模型将实现的接口:
public interface IMouseCaptureProxy
{
event EventHandler Capture;
event EventHandler Release;
void OnMouseDown(object sender, MouseCaptureArgs e);
void OnMouseMove(object sender, MouseCaptureArgs e);
void OnMouseUp(object sender, MouseCaptureArgs e);
}
public class MouseCaptureArgs
{
public double X {get; set;}
public double Y { get; set; }
public bool LeftButton { get; set; }
public bool RightButton { get; set; }
}
下面是一个使用它的行为:
public class MouseCaptureBehavior : Behavior<FrameworkElement>
{
public static readonly DependencyProperty ProxyProperty = DependencyProperty.RegisterAttached(
"Proxy",
typeof(IMouseCaptureProxy),
typeof(MouseCaptureBehavior),
new PropertyMetadata(null, OnProxyChanged));
public static void SetProxy(DependencyObject source, IMouseCaptureProxy value)
{
source.SetValue(ProxyProperty, value);
}
public static IMouseCaptureProxy GetProxy(DependencyObject source)
{
return (IMouseCaptureProxy)source.GetValue(ProxyProperty);
}
private static void OnProxyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
if (e.OldValue is IMouseCaptureProxy)
{
(e.OldValue as IMouseCaptureProxy).Capture -= OnCapture;
(e.OldValue as IMouseCaptureProxy).Release -= OnRelease;
}
if (e.NewValue is IMouseCaptureProxy)
{
(e.NewValue as IMouseCaptureProxy).Capture += OnCapture;
(e.NewValue as IMouseCaptureProxy).Release += OnRelease;
}
}
static void OnCapture(object sender, EventArgs e)
{
var behavior = sender as MouseCaptureBehavior;
if (behavior != null)
behavior.AssociatedObject.CaptureMouse();
}
static void OnRelease(object sender, EventArgs e)
{
var behavior = sender as MouseCaptureBehavior;
if (behavior != null)
behavior.AssociatedObject.ReleaseMouseCapture();
}
protected override void OnAttached()
{
base.OnAttached();
this.AssociatedObject.PreviewMouseDown += OnMouseDown;
this.AssociatedObject.PreviewMouseMove += OnMouseMove;
this.AssociatedObject.PreviewMouseUp += OnMouseUp;
}
protected override void OnDetaching()
{
base.OnDetaching();
this.AssociatedObject.PreviewMouseDown -= OnMouseDown;
this.AssociatedObject.PreviewMouseMove -= OnMouseMove;
this.AssociatedObject.PreviewMouseUp -= OnMouseUp;
}
private void OnMouseDown(object sender, MouseButtonEventArgs e)
{
var proxy = GetProxy(this);
if (proxy != null)
{
var pos = e.GetPosition(this.AssociatedObject);
var args = new MouseCaptureArgs {
X = pos.X,
Y = pos.Y,
LeftButton = (e.LeftButton == MouseButtonState.Pressed),
RightButton = (e.RightButton == MouseButtonState.Pressed)
};
proxy.OnMouseDown(this, args);
}
}
private void OnMouseMove(object sender, MouseEventArgs e)
{
var proxy = GetProxy(this);
if (proxy != null)
{
var pos = e.GetPosition(this.AssociatedObject);
var args = new MouseCaptureArgs {
X = pos.X,
Y = pos.Y,
LeftButton = (e.LeftButton == MouseButtonState.Pressed),
RightButton = (e.RightButton == MouseButtonState.Pressed)
};
proxy.OnMouseMove(this, args);
}
}
private void OnMouseUp(object sender, MouseButtonEventArgs e)
{
var proxy = GetProxy(this);
if (proxy != null)
{
var pos = e.GetPosition(this.AssociatedObject);
var args = new MouseCaptureArgs
{
X = pos.X,
Y = pos.Y,
LeftButton = (e.LeftButton == MouseButtonState.Pressed),
RightButton = (e.RightButton == MouseButtonState.Pressed)
};
proxy.OnMouseUp(this, args);
}
}
}
更新:这应该是不言而喻的,但以防万一:传递给捕获和释放事件的发送方应该与通过MouseDown/Move/Up处理程序接收到的发送方相同。传递给捕获/接收的事件参数不使用,可以为空。当鼠标使用MVVM在图像上移动时,加载图像并用rgb值显示其xy坐标的解决方案。。 希望这对一些人有帮助 视图模型:
class MainWindowViewModel : ViewModelBase
{
private Bitmap Img;
public ICommand OpenImg { get; set; }
public MainWindowViewModel()
{
OpenImg = new RelayCommand(openImg, (obj) => true);
}
private void openImg(object obj = null)
{
OpenFileDialog op = new OpenFileDialog();
op.Title = "Select a picture";
op.Filter = "All supported graphics|*.jpg;*.jpeg;*.png;*.bmp;*.tiff|" +
"JPEG (*.jpg;*.jpeg)|*.jpg;*.jpeg|" +
"Portable Network Graphic (*.png)|*.png";
if (op.ShowDialog() == true)
{
ImgPath = op.FileName;
Img = new Bitmap(ImgPath);
}
}
private string _ImgPath;
public string ImgPath
{
get
{
return _ImgPath;
}
set
{
_ImgPath = value;
OnPropertyChanged("ImgPath");
}
}
private ICommand _mouseMoveCommand;
public ICommand MouseMoveCommand
{
get
{
if (_mouseMoveCommand == null)
{
_mouseMoveCommand = new RelayCommand(param => ExecuteMouseMove((MouseEventArgs)param));
}
return _mouseMoveCommand;
}
set { _mouseMoveCommand = value; }
}
private void ExecuteMouseMove(MouseEventArgs e)
{
System.Windows.Point p = e.GetPosition(((IInputElement)e.Source));
XY = String.Format("X: {0} Y:{1}", (int)p.X, (int)p.Y);
BitmapData bd = Img.LockBits(new Rectangle(0, 0, Img.Width, Img.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
unsafe
{
byte* ptr = (byte*)bd.Scan0;
int x = (int)p.X * 3;
int y = (int)p.Y * bd.Stride;
RGB = "R: "+ptr[x + y + 2].ToString() + " G: " + ptr[x + y + 1].ToString() + " B: " + ptr[x + y].ToString();
}
Img.UnlockBits(bd);
}
private string xy;
public string XY
{
get { return xy; }
set
{
xy = value;
OnPropertyChanged("XY");
}
}
private string rgb;
public string RGB
{
get { return rgb; }
set
{
rgb = value;
OnPropertyChanged("RGB");
}
}
}
MainWindow.xaml
<Window.Resources>
<vm:MainWindowViewModel x:Key="MainWindowViewModel"/>
</Window.Resources>
<Grid DataContext="{StaticResource MainWindowViewModel}">
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
<RowDefinition Height="*" />
<RowDefinition Height="25"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<Menu FontSize="20">
<MenuItem Header="File">
<MenuItem Header="Open" Command="{Binding OpenImg}"/>
</MenuItem>
</Menu>
</Grid>
<Grid Grid.Row="1" Background="LightGray">
<Viewbox Margin="3,3,3,3">
<Image x:Name="img" Stretch="None" Source="{Binding ImgPath}"
Model:MouseBehaviour.MouseMoveCommand="{Binding MouseMoveCommand}">
</Image>
</Viewbox>
</Grid>
<Grid Grid.Row="2">
<StackPanel Orientation="Horizontal">
<TextBox Focusable="False" Text="{Binding XY}" Width="100"/>
<TextBox Focusable="False" Text="{Binding RGB}" Width="115"/>
</StackPanel>
</Grid>
</Grid>
在ViewModel中使用视图类型违反了MVVM模式,这正是OP要求避免的。@Tseng我没有使用任何视图类型,再次查看我的代码。查看MSDN并查看哪个程序集MouseCaptureArgs
defined@Tseng我没有在视图模型中使用.NET MouseCaptureArgs类,只是在行为中使用。再看看我的代码,我的错。不过,这是次优解决方案。最好改用附加属性,它们可以通过数据绑定直接绑定(即使用Rect
或Point
so),并避免使用依赖于绑定到行为的接口的过于具体的实现。然后,您可以将任何viewmodel绑定到它,而无需引用/实现该接口。对于更复杂的需求,通过dependencies属性扩展ImageView
可能更合适模型:示例中缺少鼠标行为
<!-- Canvas must have a background, even if it's Transparent -->
<Canvas Background="White" xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity">
<i:Interaction.Behaviors>
<behaviors:MouseCaptureBehavior Proxy="{Binding}" />
</i:Interaction.Behaviors>
public class MainViewModel : ViewModelBase, IMouseCaptureProxy
{
public event EventHandler Capture;
public event EventHandler Release;
public void OnMouseDown(object sender, MouseCaptureArgs e) {...}
public void OnMouseMove(object sender, MouseCaptureArgs e) {...}
public void OnMouseUp(object sender, MouseCaptureArgs e) {...}
}
class MainWindowViewModel : ViewModelBase
{
private Bitmap Img;
public ICommand OpenImg { get; set; }
public MainWindowViewModel()
{
OpenImg = new RelayCommand(openImg, (obj) => true);
}
private void openImg(object obj = null)
{
OpenFileDialog op = new OpenFileDialog();
op.Title = "Select a picture";
op.Filter = "All supported graphics|*.jpg;*.jpeg;*.png;*.bmp;*.tiff|" +
"JPEG (*.jpg;*.jpeg)|*.jpg;*.jpeg|" +
"Portable Network Graphic (*.png)|*.png";
if (op.ShowDialog() == true)
{
ImgPath = op.FileName;
Img = new Bitmap(ImgPath);
}
}
private string _ImgPath;
public string ImgPath
{
get
{
return _ImgPath;
}
set
{
_ImgPath = value;
OnPropertyChanged("ImgPath");
}
}
private ICommand _mouseMoveCommand;
public ICommand MouseMoveCommand
{
get
{
if (_mouseMoveCommand == null)
{
_mouseMoveCommand = new RelayCommand(param => ExecuteMouseMove((MouseEventArgs)param));
}
return _mouseMoveCommand;
}
set { _mouseMoveCommand = value; }
}
private void ExecuteMouseMove(MouseEventArgs e)
{
System.Windows.Point p = e.GetPosition(((IInputElement)e.Source));
XY = String.Format("X: {0} Y:{1}", (int)p.X, (int)p.Y);
BitmapData bd = Img.LockBits(new Rectangle(0, 0, Img.Width, Img.Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);
unsafe
{
byte* ptr = (byte*)bd.Scan0;
int x = (int)p.X * 3;
int y = (int)p.Y * bd.Stride;
RGB = "R: "+ptr[x + y + 2].ToString() + " G: " + ptr[x + y + 1].ToString() + " B: " + ptr[x + y].ToString();
}
Img.UnlockBits(bd);
}
private string xy;
public string XY
{
get { return xy; }
set
{
xy = value;
OnPropertyChanged("XY");
}
}
private string rgb;
public string RGB
{
get { return rgb; }
set
{
rgb = value;
OnPropertyChanged("RGB");
}
}
}
<Window.Resources>
<vm:MainWindowViewModel x:Key="MainWindowViewModel"/>
</Window.Resources>
<Grid DataContext="{StaticResource MainWindowViewModel}">
<Grid.RowDefinitions>
<RowDefinition Height="30"/>
<RowDefinition Height="*" />
<RowDefinition Height="25"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0">
<Menu FontSize="20">
<MenuItem Header="File">
<MenuItem Header="Open" Command="{Binding OpenImg}"/>
</MenuItem>
</Menu>
</Grid>
<Grid Grid.Row="1" Background="LightGray">
<Viewbox Margin="3,3,3,3">
<Image x:Name="img" Stretch="None" Source="{Binding ImgPath}"
Model:MouseBehaviour.MouseMoveCommand="{Binding MouseMoveCommand}">
</Image>
</Viewbox>
</Grid>
<Grid Grid.Row="2">
<StackPanel Orientation="Horizontal">
<TextBox Focusable="False" Text="{Binding XY}" Width="100"/>
<TextBox Focusable="False" Text="{Binding RGB}" Width="115"/>
</StackPanel>
</Grid>
</Grid>