我想在Silverlight中制作一个类似于this的颜色选择器,但我在实现大型方形区域中的游标时遇到了问题。为了跟踪鼠标状态,我有一个_isMouseDown
变量。在MouseLeave
事件_isMouseDown
设置为false
,以便如果用户拖出大方形区域,释放,然后将鼠标移回,颜色选择器光标将不会“跳转”到鼠标并跟随它(因为_isMouseDown
仍然是true
)。然而MouseLeave
事件似乎也会在光标被快速移动时触发,导致颜色选择器光标被“丢弃”。Silverlight鼠标离开问题
以下代码足以重现此问题。尝试快速拖动鼠标,椭圆将被“丢弃”。当MouseLeave
事件被删除时,问题消失。有没有办法解决这个“下降”问题,但仍然有我上面提到的行为?
XAML:
<UserControl x:Class="SilverlightApplication1.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Canvas x:Name="LayoutRoot" Width="800" Height="600">
<Rectangle Width="800" Height="600" MouseLeftButtonDown="TestMouseDown"
MouseLeftButtonUp="TestMouseUp" MouseMove="TestMouseMove"
MouseLeave="TestMouseLeave">
<Rectangle.Fill>
<LinearGradientBrush>
<GradientStop Offset="0.00" Color="Crimson" />
<GradientStop Offset="1.00" Color="Azure" />
</LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>
<Ellipse Name="TestEllipse" Width="50" Height="50" Fill="Green" />
</Canvas>
</UserControl>
C#代码隐藏:
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
namespace SilverlightApplication1
{
public partial class MainPage : UserControl
{
private bool _isMouseDown;
public MainPage()
{
InitializeComponent();
}
private void TestMouseDown(object sender, MouseButtonEventArgs e)
{
_isMouseDown = true;
UpdatePosition(e.GetPosition(LayoutRoot));
}
private void TestMouseUp(object sender, MouseButtonEventArgs e)
{
_isMouseDown = false;
}
private void TestMouseMove(object sender, MouseEventArgs e)
{
if (_isMouseDown)
UpdatePosition(e.GetPosition(LayoutRoot));
}
private void TestMouseLeave(object sender, MouseEventArgs e)
{
_isMouseDown = false;
}
private void UpdatePosition(Point point)
{
Canvas.SetLeft(TestEllipse, point.X);
Canvas.SetTop(TestEllipse, point.Y);
}
}
}