【发布时间】：2016-03-03 22:58:00
【问题描述】：
我正在尝试收集正确的 WPF 数据模板以拥有一个 Listview，该列表视图对于每个项目都有一个 Border+Canvas（请参阅 ），然后在该 Canvas 上为最终节点集合中的每个项目绘制一条线。它几乎可以工作，但目前我没有在画布上绘制线条：在我看到的调试输出窗口中：
System.Windows.Data 错误：40：BindingExpression 路径错误：在“对象”“CalloutGroup”（HashCode=35061213）上找不到“CalloutGroup”属性。 BindingExpression:Path=CalloutGroup; DataItem='CalloutGroup' (HashCode=35061213);目标元素是'ItemsControl'（名称=''）；目标属性是“ItemsSource”（类型“IEnumerable”）
这里是 MainWindow.Xaml
<Window
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:CalloutControl" x:Class="CalloutControl.MainWindow"
Title="MainWindow" Height="430.597" Width="525">
<Window.Resources>
<DataTemplate x:Key="LineTemplate">
<Line X1 ="{Binding X}" X2="{Binding X}" Stroke="Wheat"
StrokeThickness="10" Y1="{Binding Y}" Y2="{Binding Y}"/>
</DataTemplate>
<DataTemplate x:Key="GroupTemplate">
<Border Width="200" Height ="{Binding DistributionHeight}" BorderThickness="5" Background="Brown" BorderBrush="Red">
<ItemsControl ItemsSource="{Binding Path=CalloutGroup}"
ItemTemplate="{StaticResource LineTemplate}">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas Background="Beige"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
</ItemsControl>
</Border>
</DataTemplate>
</Window.Resources>
<Grid>
<Border>
<ListView ItemsSource="{Binding Groups}"
ItemTemplate="{StaticResource GroupTemplate}">
</ListView>
</Border>
</Grid>
</Window>
MainWindow.xaml.cs
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace CalloutControl
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
var vm = new MainWindowViewModel();
DataContext = vm;
}
}
}
然后是 ViewModel -> MainWindowViewModel.cs
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections.ObjectModel;
namespace CalloutControl
{
public class CalloutItem : INotifyPropertyChanged
{
public CalloutItem()
{
}
public CalloutItem (int length,
int itemNum,
double x,
double y ){
Length = length;
ItemNum = itemNum;
X = x;
Y = y;
}
private int length;
public int Length
{
get { return length; }
set
{
length = value;
OnPropertyChanged("Length");
}
}
private int itemNum;
public int ItemNum
{
get { return itemNum; }
set { itemNum = value;
OnPropertyChanged("ItemNum");
}
}
//public int ItemNum;
private double x;
public double X
{
get { return x; }
set { x = value;
OnPropertyChanged("X");
}
}
private double y;
public double Y
{
get { return y; }
set { y = value;
OnPropertyChanged("Y");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
public class CalloutGroup : INotifyPropertyChanged
{
ObservableCollection<CalloutItem> group = new ObservableCollection<CalloutItem>();
public CalloutGroup(int nItems)
{
NumItems = nItems;
}
public ObservableCollection<CalloutItem> Group
{
get { return group; }
set
{
group = value;
OnPropertyChanged("Group");
}
}
private double distributionHeight = 400;
public double DistributionHeight
{
get { return distributionHeight; }
set
{
distributionHeight = value;
Redistribute();
OnPropertyChanged("DistributionHeight");
}
}
private void Redistribute()
{
double step = distributionHeight / numItems;
double currY = step / 2 ;
var redistArr = group.ToArray();
for (int i = 0; i < group.Count(); i++)
{
redistArr[i].Y = currY;
currY += step;
}
OnPropertyChanged("Group");
}
private int numItems = 10;
public int NumItems
{
get { return numItems; }
set
{
numItems = value;
group.Clear();
for (int i = 0; i < numItems; i++)
{
group.Add(new CalloutItem());
}
Redistribute();
OnPropertyChanged("NumItems");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
public class MainWindowViewModel : INotifyPropertyChanged
{
ObservableCollection<CalloutGroup> groups = new ObservableCollection<CalloutGroup>();
public ObservableCollection<CalloutGroup> Groups
{
get { return groups; }
set { groups = value;
OnPropertyChanged("Groups");
}
}
public MainWindowViewModel ()
{
groups.Add(new CalloutGroup(3));
groups.Add(new CalloutGroup(3));
}
public event PropertyChangedEventHandler PropertyChanged;
protected void OnPropertyChanged(string name)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null)
{
handler(this, new PropertyChangedEventArgs(name));
}
}
}
}
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标签： c# wpf xaml wpf-controls datatemplate