我想在 WPF 中模拟拖/放事件。
为此,我需要访问存储在“拖/放缓冲区”中的数据,并且还需要创建一个 DragEventArgs
。
我注意到 DragEventArgs
是密封的并且没有公共(public) ctor。
所以我的问题是:
1. 如何创建 DragEventArgs
的实例?
2. 如何访问拖/放缓冲区?
最佳答案
我最近这样做了!我用 MouseDown、MouseMove 和 MouseUp 事件模拟了拖/放。例如,对于我的应用程序,我有一些 Canvas ,我想拖放它们。每个 Canvas 都有一个 id。在 MouseDown 事件中,我缓冲其 id 并在 MouseMove 和 MouseUp 事件中使用它。 Desktop_Canvas 是我的主要 Canvas ,其中包含一些 Canvas 。这些 Canvas 在我的字典(dic)中。
这是我的代码:
private Dictionary<int, Win> dic = new Dictionary<int, Win>();
private Point downPoint_Drag = new Point(-1, -1);
private int id_Drag = -1;
private bool flag_Drag = false;
public class Win
{
public Canvas canvas = new Canvas();
public Point downpoint = new Point();
public Win()
{
canvas.Background = new SolidColorBrush(Colors.Gray);
}
}
private void Desktop_Canvas_MouseMove(object sender, MouseEventArgs e)
{
try
{
Point movePoint = e.GetPosition(Desktop_Canvas);
if (flag_Drag && downPoint_Drag != new Point(-1, -1))
{
double dy1 = movePoint.Y - downPoint_Drag.Y, x = -1, dx1 = movePoint.X - downPoint_Drag.X, y = -1;
downPoint_Drag = movePoint;
if (x == -1)
x = Canvas.GetLeft(dic[id_Drag].canvas) + dx1;
if (y == -1)
y = Canvas.GetTop(dic[id_Drag].canvas) + dy1;
Canvas.SetLeft(dic[id_Drag].canvas, x);
Canvas.SetTop(dic[id_Drag].canvas, y);
}
}
catch
{
MouseEventArgs ee = new MouseEventArgs((MouseDevice)e.Device, 10);
Desktop_Canvas_MouseLeave(null, ee);
}
}
private void Desktop_Canvas_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
try
{
downPoint_Drag = new Point(-1, -1);
id_Drag =-1;
flag_Drag = false;
}
catch
{
MouseEventArgs ee = new MouseEventArgs((MouseDevice)e.Device, 10);
Desktop_Canvas_MouseLeave(null, ee);
}
}
private void Desktop_Canvas_MouseLeave(object sender, MouseEventArgs e)
{
MouseButtonEventArgs ee = new MouseButtonEventArgs((MouseDevice)e.Device, 10, MouseButton.Left);
Desktop_Canvas_MouseLeftButtonUp(null, ee);
}
void canvas_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
downPoint_Drag = e.GetPosition(Desktop_Canvas);
int hoverId = HoverWin(downPoint_Drag);
flag_Drag = true;
id_Drag = hoverId;
dic[id_Drag].downpoint = new Point(downPoint_Drag.X, downPoint_Drag.Y);
}
private int HoverWin(Point p)
{
foreach (int i in dic.Keys)
{
if (dic[i].canvas.IsMouseOver)
return i;
}
return -1;
}
关于wpf - 在 WPF 中模拟拖/放事件,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/15130712/