路径图和数据绑定 [英] Path drawing and data binding
问题描述
我正在寻找一种能够使用wpf Path元素来绘制路由的方法,该路径将在地图上表示路由。我有一个Route类,其中包含一组顶点,并希望使用它来进行绑定。我真的不知道如何开始..
任何提示?
I am looking for a way to be able to use the wpf Path element to draw a path that will represent a route on the map. I have the Route class that contains a collection of vertices and would like to use it for binding. I don't really know how to even start.. Any hints?
推荐答案
主要的事情你会需要绑定是一个转换器,将您的点转换为几何
,路径将需要为数据
,这里是什么我的单向转换器从 System.Windows.Point
-array到几何看起来像:_
The main thing you'll need for the binding is a converter that turns your points into Geometry
which the path will need as Data
, here is what my one-way converter from a System.Windows.Point
-array to Geometry looks like:
[ValueConversion(typeof(Point[]), typeof(Geometry))]
public class PointsToPathConverter : IValueConverter
{
#region IValueConverter Members
public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
Point[] points = (Point[])value;
if (points.Length > 0)
{
Point start = points[0];
List<LineSegment> segments = new List<LineSegment>();
for (int i = 1; i < points.Length; i++)
{
segments.Add(new LineSegment(points[i], true));
}
PathFigure figure = new PathFigure(start, segments, false); //true if closed
PathGeometry geometry = new PathGeometry();
geometry.Figures.Add(figure);
return geometry;
}
else
{
return null;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotSupportedException();
}
#endregion
}
现在所有这一切都是为了创建一个实例,并将其用作绑定的转换器。在XAML中可能是什么样子:
Now all that is really left is to create an instance of it and use it as the converter for the binding. What it might look like in XAML:
<Grid>
<Grid.Resources>
<local:PointsToPathConverter x:Key="PointsToPathConverter"/>
</Grid.Resources>
<Path Data="{Binding ElementName=Window, Path=Points, Converter={StaticResource ResourceKey=PointsToPathConverter}}"
Stroke="Black"/>
</Grid>
如果您需要绑定来自动更新,您应该使用依赖属性或接口,如 INotifyPropertyChanged
/ INotifyCollectionChanged
希望有助于:D
If you need the binding to update automatically you should work with dependency properties or interfaces like INotifyPropertyChanged
/INotifyCollectionChanged
Hope that helps :D
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