以下是我的XAML代码。我在Canvas中放置了一张图片。当鼠标在图片上拖动时,我想在图片上绘制矩形。在WPF中,我已经成功实现了这个功能。但是现在我想使用MVVM来实现它。我想把事件处理程序放在ViewModel中,而不是放在代码后面。我正在使用MVVM Foundation来实现MVVM。以下是MVVM Foundation的链接:http://mvvmfoundation.codeplex.com/
非常感谢您的帮助。
XAML
<Canvas Name="cnvImage">
<Image Height="348" HorizontalAlignment="Left" Margin="12,39,0,0" Name="imgPreview"
Stretch="Fill" VerticalAlignment="Top" Width="443"
Source="/Images/CapturedImage.png"
MouseDown="imgCamera_MouseDown" MouseMove="imgCamera_MouseMove" MouseUp="imgCamera_MouseUp" />
</Canvas>
在代码后台编写的代码
// This is the rectangle to be shown when mouse is dragged on camera image.
private Point startPoint;
private Rectangle rectSelectArea;
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void imgCamera_MouseDown(object sender, MouseButtonEventArgs e)
{
startPoint = e.GetPosition(cnvImage);
// Remove the drawn rectanglke if any.
// At a time only one rectangle should be there
if (rectSelectArea != null)
cnvImage.Children.Remove(rectSelectArea);
// Initialize the rectangle.
// Set border color and width
rectSelectArea = new Rectangle
{
Stroke = Brushes.LightBlue,
StrokeThickness = 2
};
Canvas.SetLeft(rectSelectArea, startPoint.X);
Canvas.SetTop(rectSelectArea, startPoint.X);
cnvImage.Children.Add(rectSelectArea);
}
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void imgCamera_MouseMove(object sender, MouseEventArgs e)
{
if (e.LeftButton == MouseButtonState.Released || rectSelectArea == null)
return;
var pos = e.GetPosition(cnvImage);
// Set the position of rectangle
var x = Math.Min(pos.X, startPoint.X);
var y = Math.Min(pos.Y, startPoint.Y);
// Set the dimenssion of the rectangle
var w = Math.Max(pos.X, startPoint.X) - x;
var h = Math.Max(pos.Y, startPoint.Y) - y;
rectSelectArea.Width = w;
rectSelectArea.Height = h;
Canvas.SetLeft(rectSelectArea, x);
Canvas.SetTop(rectSelectArea, y);
}
/// <summary>
///
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void imgCamera_MouseUp(object sender, MouseButtonEventArgs e)
{
rectSelectArea = null;
}
我需要知道在我的视图模型中需要写什么,以及相应的XAML需要做出哪些更改。
提前感谢。
ViewModel
)。 - Rachel