purpose:use your Finger to draw a polyline,then use the OnHolding Event end of the draw.
the complete code is as follows：
PolyLineContainer.cs
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
namespace test1
{
public class PolyLineContainer : Panel
{
protected override Size MeasureOverride(Size availableSize)
{
foreach (UIElement element in base.Children)
{
element.Measure(availableSize);
}
return base.MeasureOverride(availableSize);
}
protected override Size ArrangeOverride(Size finalSize)
{
foreach (UIElement element in base.Children)
{
var line = element as PolyLineElement;
var points = line.pc;
if (points.Count == 0) continue;
var left = points[0].X;
var top = points[0].Y;
var right = points[0].X;
var bottom = points[0].Y;
for (var i = 1; i < points.Count; i++)
{
var p = points[i];
if (left > p.X) left = p.X;
if (top > p.Y) top = p.Y;
if (right < p.X) right = p.X;
if (bottom < p.Y) bottom = p.Y;
}
var w = right - left;
var h = bottom - top;
if (w > 0 && h > 0)
{
element.Arrange(new Rect(left, top, w+50, h+50));
//Debug.WriteLine("container--x:" + left + "'top:" + top + ",width:" + w + ",height:" + h);
foreach (Point p in line.Points)
{
//Debug.WriteLine("change--X:" + p.X + "'Y:" + p.Y);
}
foreach (Point p in line.pc)
{
//Debug.WriteLine("origin--X:" + p.X + "'Y:" + p.Y);
}
}
else
{
element.Arrange(new Rect(new Point(0, 0), element.DesiredSize));
}
}
return base.ArrangeOverride(finalSize);
}
}
}
PolyLineElement.cs
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Foundation;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Shapes;
namespace test1
{
public class PolyLineElement : UserControl
{
public Point2DCollection pc
{
get { return (Point2DCollection)GetValue(pcProperty); }
set { SetValue(pcProperty, value); }
}
public static readonly DependencyProperty pcProperty = DependencyProperty.Register("pc", typeof(Point2DCollection), typeof(PolyLineElement), new PropertyMetadata(null, new PropertyChangedCallback(Point2Ds_Changed)));
private static void Point2Ds_Changed(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
PolyLineElement sb = o as PolyLineElement;
if (sb != null)
{
Point2DCollection oldValue = e.OldValue as Point2DCollection;
if (oldValue != null)
{
oldValue.CollectionChanged -= new NotifyCollectionChangedEventHandler(sb.Point2Ds_CollectionChanged);
}
Point2DCollection newValue = e.NewValue as Point2DCollection;
if (newValue != null)
{
newValue.CollectionChanged += new NotifyCollectionChangedEventHandler(sb.Point2Ds_CollectionChanged);
}
sb.ScreenUpdated();
}
}
private void Point2Ds_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
this.ScreenUpdated();
}
private void ScreenUpdated()
{
var points = this.pc;
if (points.Count == 0) return;
var left = points[0].X;
var top = points[0].Y;
var right = points[0].X;
var bottom = points[0].Y;
for (var i = 1; i < points.Count; i++)
{
var p = points[i];
if (left > p.X) left = p.X;
if (top > p.Y) top = p.Y;
if (right < p.X) right = p.X;
if (bottom < p.Y) bottom = p.Y;
}
//Debug.WriteLine("line--x:" + left + "'top:" + top + ",width:" + (right - left) + ",height:" + (bottom - top));
var pointsc = new PointCollection();
foreach (Point p in points)
{
var pp = new Point(p.X, p.Y);
pp.X -= left;
pp.Y -= top;
pointsc.Add(pp);
}
this.Points = pointsc;
}
public PointCollection Points
{
get
{
return ((Polyline)this.shape).Points;
}
set
{
((Polyline)this.shape).Points = value;
}
}
private Shape shape;
public PolyLineElement()
{
base.Content = this.shape = new Polyline();
pc = new Point2DCollection();
}
public Brush Stroke
{
get
{
return (Brush)this.shape.GetValue(Shape.StrokeProperty);
}
set
{
this.shape.SetValue(Shape.StrokeProperty, value);
}
}
public double StrokeThickness
{
get
{
return (double)this.shape.GetValue(Shape.StrokeThicknessProperty);
}
set
{
this.shape.SetValue(Shape.StrokeThicknessProperty, value);
}
}
}
}
Point2DCollection.cs
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Windows.Foundation;
namespace test1
{
public class Point2DCollection : ObservableCollection<Point>
{
public double x{get;set;}
public double y{get;set;}
public double w{get;set;}
public double h{get;set;}
public Point2DCollection()
{
}
}
}
start page
MainPage.xaml
<Page
x:Class="test1.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:test1"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Name="grid" Background="{StaticResource ApplicationPageBackgroundThemeBrush}" PointerPressed="grid_PointerPressed_1" PointerMoved="grid_PointerMoved_1" Holding="grid_Holding_1">
<Grid HorizontalAlignment="Stretch" VerticalAlignment="Stretch" Background="Black" Opacity="1">
<Polyline Name="line" Stroke="AntiqueWhite" StrokeThickness="6"/>
</Grid>
</Grid>
</Page>
MainPage.xaml.cs
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using Windows.Devices.Input;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI;
using Windows.UI.Input;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media;
using Windows.UI.Xaml.Navigation;
// “空白页”项模板在 http://go.microsoft.com/fwlink/?LinkId=234238 上有介绍
namespace test1
{
/// <summary>
/// 可用于自身或导航至 Frame 内部的空白页。
/// </summary>
public sealed partial class MainPage : Page
{
private PolyLineContainer container;
private bool isFirst = true;
private PolyLineElement le;
public MainPage()
{
this.InitializeComponent();
}
/// <summary>
/// 在此页将要在 Frame 中显示时进行调用。
/// </summary>
/// <param name="e">描述如何访问此页的事件数据。Parameter
/// 属性通常用于配置页。</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
if (e.NavigationMode == NavigationMode.New)
{
container = new PolyLineContainer();
grid.Children.Add(container);
}
}
private void grid_PointerPressed_1(object sender, PointerRoutedEventArgs e)
{
var p = e.GetCurrentPoint(grid).Position;
if (isFirst)
{
isFirst = false;
le = new PolyLineElement();
le.Stroke = new SolidColorBrush(Colors.White);
le.StrokeThickness = 1;
container.Children.Add(le);
le.Points.Add(p);
le.pc.Add(p);
}
le.pc.Add(p);
}
private void grid_PointerMoved_1(object sender, PointerRoutedEventArgs e)
{
if (le == null || le.pc.Count == 0) return;
var p = e.GetCurrentPoint(grid).Position;
le.pc.RemoveAt(le.pc.Count - 1);
le.pc.Add(p);
}
private void grid_Holding_1(object sender, HoldingRoutedEventArgs e)
{
if (e.HoldingState == HoldingState.Started)
{
isFirst = true;
le.pc.Clear();
}
}
}
}
Test Results
via the touch screen, the OnHolding Event can not be triggered sometimes. why?
