WPF渲染事件不领取任何 [英] WPF Render Event Not Drawing Anything
问题描述
我试图将一些WinForm的code到WPF的管网图纸的应用程序。我一直立足而过这种涂料的应用文章：
I'm trying to convert some WinForm code to WPF for a pipe network drawing app. I've been basing it off this paint app article:
HTTP：//www.$c$cproject.com/Articles/ 22776 / WPF-DrawTools
这是我在WinForms和我想是因为我们需要更多的自定义窗口，将其转换过来。我需要做到以下几点：
This is what I had in WinForms and I'm trying to convert it over because we need more customizable windows. I need to do the following:
a）单击画布绘制节点 b）点击并拖动上述节点 C）将鼠标悬停在和突出节点 D）连接与连接节点
a) Click the canvas to draw nodes b) Click and drag aforementioned nodes c) Hover over and highlight nodes d) connect nodes with links
我有以下的code画在画布上的一个矩形，但什么都不会出现在画布上绘制时触发。我比较肯定它解雇了，因为把一个消息框，它会导致程序崩溃。
I have the following code to draw a rectangle on a canvas, but nothing will appear on the canvas when render is fired. I'm relatively sure it's fired because putting a message box in it causes the program to crash.
protected override void OnRender(DrawingContext drawingContext)
{
base.OnRender(drawingContext);
SolidColorBrush mySolidColorBrush = new SolidColorBrush();
mySolidColorBrush.Color = Colors.LimeGreen;
Pen myPen = new Pen(Brushes.Blue, 10);
Rect myRect = new Rect(50, 50, 500, 500);
drawingContext.DrawRectangle(mySolidColorBrush, myPen, myRect);
}
private void myCanvas_MouseDown(object sender, MouseButtonEventArgs e)
{
System.Windows.Forms.MessageBox.Show("click event fired");
DrawingVisual vs = new DrawingVisual();
DrawingContext dc = vs.RenderOpen();
OnRender(dc);
}
在炒鱿鱼的消息框就是在那里，以确保click事件触发，而且它。 XML：
The "fired" message box is just in there to make sure the click event fires, and it does. XML:
<TabItem Header="View Results">
<Canvas Background="WhiteSmoke" Name="myCanvas" MouseDown="myCanvas_MouseDown" >
</Canvas>
</TabItem>
怎么办？在文章的人使用用户的控制......这是为什么我有问题？ WPF驱使我坚果...我觉得如果我做一些完全错误的，但很少有文件，我可以找到关于这个问题的。
What gives? The guy in the article uses a user control... is that why I'm having problems? WPF drives me nuts... I feel as if I am doing something completely wrong but there is very little documentation that I can find on the subject.
推荐答案
你看，这是一个简单的例子，我在20分钟内制作：
Look this is a simple example I made in 20 minutes:
XAML：
<Window x:Class="NodesEditor.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:NodesEditor"
Title="Window1" Height="800" Width="800" x:Name="view">
<Grid Margin="10">
<Grid.Resources>
<!-- This CompositeCollection basically Concatenates the Nodes and Connectors in a single one -->
<CompositeCollection x:Key="Col">
<CollectionContainer Collection="{Binding DataContext.Connectors,Source={x:Reference view}}"/>
<CollectionContainer Collection="{Binding DataContext.Nodes,Source={x:Reference view}}"/>
</CompositeCollection>
<!-- This is the DataTemplate that will be used to render the Node class -->
<DataTemplate DataType="{x:Type local:Node}">
<Thumb DragDelta="Thumb_Drag">
<Thumb.Template>
<ControlTemplate TargetType="Thumb">
<Ellipse Height="10" Width="10" Stroke="Black" StrokeThickness="1" Fill="Blue"
Margin="-5,-5,5,5" x:Name="Ellipse"/>
<ControlTemplate.Triggers>
<Trigger Property="IsDragging" Value="True">
<Setter TargetName="Ellipse" Property="Fill" Value="Yellow"/>
</Trigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Thumb.Template>
</Thumb>
</DataTemplate>
<!-- This is the DataTemplate that will be used to render the Connector class -->
<DataTemplate DataType="{x:Type local:Connector}">
<Line Stroke="Black" StrokeThickness="1"
X1="{Binding Start.X}" Y1="{Binding Start.Y}"
X2="{Binding End.X}" Y2="{Binding End.Y}"/>
</DataTemplate>
</Grid.Resources>
<!-- This Border serves as a background and the VisualBrush used to paint its background serves as the "Snapping Grid" -->
<!-- The "Snapping" Actually occurs in the Node class (see Node.X and Node.Y properties), it has nothing to do with any UI Elements -->
<Border>
<Border.Background>
<VisualBrush TileMode="Tile"
Viewport="0,0,50,50" ViewportUnits="Absolute"
Viewbox="0,0,50,50" ViewboxUnits="Absolute">
<VisualBrush.Visual>
<Rectangle Stroke="Darkgray" StrokeThickness="1" Height="50" Width="50"
StrokeDashArray="5 3"/>
</VisualBrush.Visual>
</VisualBrush>
</Border.Background>
</Border>
<ItemsControl>
<ItemsControl.ItemsSource>
<StaticResource ResourceKey="Col"/>
</ItemsControl.ItemsSource>
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas IsItemsHost="True"/>
</ItemsPanelTemplate>
</ItemsControl.ItemsPanel>
<ItemsControl.ItemContainerStyle>
<Style TargetType="ContentPresenter">
<Setter Property="Canvas.Left" Value="{Binding X}"/>
<Setter Property="Canvas.Top" Value="{Binding Y}"/>
</Style>
</ItemsControl.ItemContainerStyle>
</ItemsControl>
</Grid>
</Window>
code背后：
Code Behind:
using System.Collections.Generic;
using System.Linq;
using System.Windows;
using System.Windows.Controls.Primitives;
namespace NodesEditor
{
public partial class MainWindow : Window
{
public List<Node> Nodes { get; set; }
public List<Connector> Connectors { get; set; }
public MainWindow()
{
InitializeComponent();
Nodes = NodesDataSource.GetRandomNodes().ToList();
Connectors = NodesDataSource.GetRandomConnectors(Nodes).ToList();
DataContext = this;
}
private void Thumb_Drag(object sender, DragDeltaEventArgs e)
{
var thumb = sender as Thumb;
if (thumb == null)
return;
var data = thumb.DataContext as Node;
if (data == null)
return;
data.X += e.HorizontalChange;
data.Y += e.VerticalChange;
}
}
}
数据模型：
public class Node: INotifyPropertyChanged
{
private double _x;
public double X
{
get { return _x; }
set
{
//"Grid Snapping"
//this actually "rounds" the value so that it will always be a multiple of 50.
_x = (Math.Round(value / 50.0)) * 50;
OnPropertyChanged("X");
}
}
private double _y;
public double Y
{
get { return _y; }
set
{
//"Grid Snapping"
//this actually "rounds" the value so that it will always be a multiple of 50.
_y = (Math.Round(value / 50.0)) * 50;
OnPropertyChanged("Y");
}
}
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void OnPropertyChanged(string propertyName)
{
PropertyChangedEventHandler handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
public class Connector
{
public Node Start { get; set; }
public Node End { get; set; }
}
随机数据源（要填的东西的例子）
Random Data Source (To fill the example with something)
using System;
using System.Collections.Generic;
using System.Linq;
namespace NodesEditor
{
public static class NodesDataSource
{
public static Random random = new Random();
public static Node GetRandomNode()
{
return new Node
{
X = random.Next(0,500),
Y = random.Next(0,500)
};
}
public static IEnumerable<Node> GetRandomNodes()
{
return Enumerable.Range(5, random.Next(6, 10)).Select(x => GetRandomNode());
}
public static Connector GetRandomConnector(IEnumerable<Node> nodes)
{
return new Connector { Start = nodes.FirstOrDefault(), End = nodes.Skip(1).FirstOrDefault() };
}
public static IEnumerable<Connector> GetRandomConnectors(List<Node> nodes)
{
var result = new List<Connector>();
for (int i = 0; i < nodes.Count() - 1; i++)
{
result.Add(new Connector() {Start = nodes[i], End = nodes[i + 1]});
}
return result;
}
}
}
这是什么样子在我的电脑：
This is what it looks like in my Computer:
这篇关于WPF渲染事件不领取任何的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
