我想在Silverlight中製作一個類似於this的顏色選擇器,但我在實現大型方形區域中的遊標時遇到了問題。爲了跟蹤鼠標狀態,我有一個_isMouseDown
變量。在MouseLeave
事件_isMouseDown
設置爲false
,以便如果用戶拖出大方形區域,釋放,然後將鼠標移回,顏色選擇器光標將不會「跳轉」到鼠標並跟隨它(因爲_isMouseDown
仍然是true
)。然而MouseLeave
事件似乎也會在光標被快速移動時觸發,導致顏色選擇器光標被「丟棄」。Silverlight鼠標離開問題
以下代碼足以重現此問題。嘗試快速拖動鼠標,橢圓將被「丟棄」。當MouseLeave
事件被刪除時,問題消失。有沒有辦法解決這個「下降」問題,但仍然有我上面提到的行爲?
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#代碼隱藏:
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);
}
}
}