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解决方案 窗口拖动时的动态边距

所以我试图让我的多边形随着窗口的移动而移动。我有;

    private void ResetPolygon(Point Point1, Point Point2, Point Point3)
    {
        SpeechPoly.Points.Clear();
        ObservableCollection<Point> myPointCollection = new ObservableCollection<Point>();
        myPointCollection.Add(Point3);
        myPointCollection.Add(Point2);
        myPointCollection.Add(Point1);
        foreach (Point p in myPointCollection)
        {
            SpeechPoly.Points.Add(p);
        }
    }

    private void Window_LocationChanged(object sender, EventArgs e)
    {
        if (this.IsLoaded)
        {
            Point Point1 = new Point(newPoint3);
            Point Point2 = new Point(newPoint2);
            Point Point3 = new Point(newPoint1);
            ResetPolygon(newPoint1, newPoint2, newPoint3);

//Write out the values of both the list and the polygon to screen!
            txtBlock.Text = newPoint1.X.ToString("N2") + ", " + newPoint1.Y.ToString("N2") + 
"\n" + newPoint2.X.ToString("N2") + ", " + newPoint2.Y.ToString("N2") + "\n" + 
newPoint3.X.ToString("N2") + ", " + newPoint3.Y.ToString("N2");

            txtBlock.Text += "\n" + SpeechPoly.Points[0].X.ToString("N2") + ", " + 
SpeechPoly.Points[0].Y.ToString("N2") + "\n" + SpeechPoly.Points[1].X.ToString("N2") + ", " +        
SpeechPoly.Points[1].Y.ToString("N2") + "\n" + SpeechPoly.Points[2].X.ToString("N2") + ", "+ 
SpeechPoly.Points[2].Y.ToString("N2");
                        }
                    }

但是多边形无论如何都保持相同的形状，即使Textblock清楚地显示了所有点的值Points和List点Polygon肯定在变化。

我还尝试将 的Points属性绑定Polygon到我的代码。

<Polygon
    Name="SpeechPoly"
    Points="{Binding myPointCollection, RelativeSource={RelativeSource FindAncestor, AncestorType=Window}}"
    Stroke="Black" 
    StrokeThickness="2"
    </Polygon>

我也尝试过使用pointsCollection相反List<Points>但相同的结果。几乎看起来Polygon并不令人耳目一新。

4

3 回答 3

2

我对我之前给出的答案并不满意，因为它毕竟是一种解决方法..

我找到了一个更好的解决方案，不需要重置数据绑定。

因此，来自 XAML 的绑定被定向到具有 INCC 的属性，但是数据本身被转换为点以供多边形在绘制时使用。

<Window x:Class="WpfApplication9.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WpfApplication9"
    Title="MainWindow" Height="350" Width="525" LocationChanged="Window_LocationChanged" >
<Window.Resources>
    <local:MyPointCollectionConverter x:Key="mcolconv" />
</Window.Resources>
<Canvas>
    <Polygon Name="SpeechPoly" Stroke="Black" StrokeThickness="2" 
             Points="{Binding Path=myPointCollection, Converter={StaticResource mcolconv}}" />
</Canvas>


using System;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Windows;
using System.Windows.Data;
using System.Windows.Media;

namespace WpfApplication9
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window, INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;

    private ObservableCollection<Point> _myPointCollection = new ObservableCollection<Point>();
    public ObservableCollection<Point> myPointCollection { get { return _myPointCollection; } }

    public MainWindow()
    {
        myPointCollection.Add(new Point(100, 50));
        myPointCollection.Add(new Point(150, 100));
        myPointCollection.Add(new Point(50, 100));
        InitializeComponent();
        DataContext = this;
    }

    private void ResetPolygon(Point Point1, Point Point2, Point Point3)
    {
        myPointCollection.Clear();
        myPointCollection.Add(Point1);
        myPointCollection.Add(Point2);
        myPointCollection.Add(Point3);
        if (PropertyChanged != null)
            PropertyChanged(this, new PropertyChangedEventArgs("myPointCollection"));
    }

    private void Window_LocationChanged(object sender, EventArgs e)
    {
        if (this.IsLoaded)
        {
            Random rnd = new Random();
            Point Point1 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            Point Point2 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            Point Point3 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            ResetPolygon(Point1, Point2, Point3);
        }

    }
}

public class MyPointCollectionConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        var regPtsColl = new PointCollection(); //regular points collection.
        var obsPtsColl = (ObservableCollection<Point>)value; //observable which is used to raise INCC event.
        foreach (var point in obsPtsColl)
            regPtsColl.Add(point);
        return regPtsColl;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        return null;
    }

    #endregion
}
}
于 2012-07-07T14:44:06.623 回答
0

PointsCollection 没有使用 INotifyCollectionChanged..
所以绑定永远不会知道某事已经改变。

您可以通过刷新绑定来解决此问题。

这是一个执行您要求的示例：

<Window x:Class="WpfApplication9.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525" LocationChanged="Window_LocationChanged" >
<Canvas>
    <Polygon Name="SpeechPoly" Stroke="Black" StrokeThickness="2" Points="{Binding Path=myPointCollection}" />
</Canvas>


using System;
using System.Windows;
using System.Windows.Media;

namespace WpfApplication9
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    public PointCollection myPointCollection { get; set; }

    public MainWindow()
    {
        myPointCollection = new PointCollection
        {
            new Point(100, 50),
            new Point(150, 100),
            new Point(50, 100)
        };
        InitializeComponent();
        DataContext = this;
    }

    private void ResetPolygon(Point Point1, Point Point2, Point Point3)
    {
        myPointCollection[0] = Point1;
        myPointCollection[1] = Point2;
        myPointCollection[2] = Point3;
        DataContext = null;
        DataContext = this;
    }

    private void Window_LocationChanged(object sender, EventArgs e)
    {
        if (this.IsLoaded)
        {
            Random rnd = new Random();
            Point Point1 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            Point Point2 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            Point Point3 = new Point(rnd.Next(50, 200), rnd.Next(50, 200));
            ResetPolygon(Point1, Point2, Point3);
        }

    }
}

}
于 2012-07-06T17:17:39.993 回答
0

那么你在Window_LocationChanged处理程序中所做的就是添加点，所以难怪你最终会得到更多的多边形。您myPointCollection必须是ObservableCollection，并且您必须在添加点之前清除集合。我还想知道您是否可以使用从Point( System.Windows.Point) 继承的类，但将 x 和 y 重载给NotifyingPropertyChanged它们，以便绑定可以更新。如果可行，您不必再更改 Collection，而是更改 Collection 内容。

更新后编辑：

看起来问题出在您的更新中：因为您使用相同的 Collection 更新它，所以不会发生更新。
这是完全正常的行为，因为 Collection (a PointCollection) 没有实现CollectionChanged，所以即使你清除它，所有 clr '看到'都是同一个对象，所以没有变化，因此没有更新。

您不应该修改（清除）Xaml Polygon 对象本身的点集合，因为绑定就足够了。

  1. PointCollection尝试每次创建一个新点，添加点，然后将列表分配给 Polygon Points 。

  2. 或尝试制作通知点并更改点。也许你可以用空字符串“”通知 X 和 Y，这意味着一切都改变了，或者用“X”通知 X，用“Y”通知 Y。

于 2012-06-29T15:09:21.273 回答