我有以下代码将图像拖放到Canvas中:
img.AllowDrop = true;
img.PreviewMouseLeftButtonDown += this.MouseLeftButtonDown;
img.PreviewMouseMove += this.MouseMove;
img.PreviewMouseLeftButtonUp += this.PreviewMouseLeftButtonUp;
private object movingObject;
private double firstXPos, firstYPos;
private void MouseLeftButtonDown(object sender, MouseButtonEventArgs e) {
// In this event, we get the current mouse position on the control to use it in the MouseMove event.
Image img = sender as Image;
Canvas canvas = img.Parent as Canvas;
firstXPos = e.GetPosition(img).X;
firstYPos = e.GetPosition(img).Y;
movingObject = sender;
// Put the image currently being dragged on top of the others
int top = Canvas.GetZIndex(img);
foreach (Image child in canvas.Children)
if (top < Canvas.GetZIndex(child))
top = Canvas.GetZIndex(child);
Canvas.SetZIndex(img, top + 1);
}
private void PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e) {
Image img = sender as Image;
Canvas canvas = img.Parent as Canvas;
movingObject = null;
// Put the image currently being dragged on top of the others
int top = Canvas.GetZIndex(img);
foreach (Image child in canvas.Children)
if (top > Canvas.GetZIndex(child))
top = Canvas.GetZIndex(child);
Canvas.SetZIndex(img, top + 1);
}
private void MouseMove(object sender, MouseEventArgs e) {
if (e.LeftButton == MouseButtonState.Pressed && sender == movingObject) {
Image img = sender as Image;
Canvas canvas = img.Parent as Canvas;
double newLeft = e.GetPosition(canvas).X - firstXPos - canvas.Margin.Left;
// newLeft inside canvas right-border?
if (newLeft > canvas.Margin.Left + canvas.ActualWidth - img.ActualWidth)
newLeft = canvas.Margin.Left + canvas.ActualWidth - img.ActualWidth;
// newLeft inside canvas left-border?
else if (newLeft < canvas.Margin.Left)
newLeft = canvas.Margin.Left;
img.SetValue(Canvas.LeftProperty, newLeft);
double newTop = e.GetPosition(canvas).Y - firstYPos - canvas.Margin.Top;
// newTop inside canvas bottom-border?
if (newTop > canvas.Margin.Top + canvas.ActualHeight - img.ActualHeight)
newTop = canvas.Margin.Top + canvas.ActualHeight - img.ActualHeight;
// newTop inside canvas top-border?
else if (newTop < canvas.Margin.Top)
newTop = canvas.Margin.Top;
img.SetValue(Canvas.TopProperty, newTop);
}
}
此代码使我可以将图像拖放到Canvas内,而无需离开Canvas本身.
现在,我只需要能够做两件事:
>修复一个小错误,当我快速拖动鼠标时,鼠标会滑过图像.即使我什至没有快速移动拖动图像,也经常发生这种情况.
>使其能够一次拖放多个图像,最好是先选择多个图像,然后再将整堆图像拖放到画布中,同时保留在画布内.
PS:我以前的问题可以找到here.
解决方法:
You’ll want to lock the mouse on to the image to stop the cursor slipping off it Mouse.Capture (imageReference), you can release it on mouse up with Mouse.Capture (null) – Andy Feb 18 at 15:58
在使用Andy的建议之后,添加以下内容:
Mouse.Capture(img);
在MouseLeftButtonDown函数的底部,然后
Mouse.Capture(null);
在PreviewMouseLeftButtonUp函数底部,它就像一个超级按钮.非常感谢Andy!