在按钮上画一条线单击 [英] Draw a line on button Click

问题描述

我想让用户画一条线，就像我们在绘画应用程序中画线一样，这是我的代码


MainWindow.xaml的xaml代码

I want to let user draw a line like we draw in a paint application following is my code


xaml code for MainWindow.xaml

<Window x:Class="LineWPF.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">
    <DockPanel LastChildFill="True">
        <Button Name="buttonToolLine" DockPanel.Dock="Top" Height="41" MouseDown="buttonToolLine_MouseDown" MouseMove="buttonToolLine_MouseMove">Line</Button>
            <Canvas Name="DrawingCanvas"></Canvas>
    </DockPanel>

</Window>

以下是我背后的代码MainWindow.xaml.cs

Following is my behind the code MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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;
using System.IO;

namespace LineWPF
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {

        Point StartPoint;
        Point EndPoint;
        Line CurrentLine;
        public MainWindow()
        {
            InitializeComponent();
        }

         void buttonToolLine_MouseDown(object sender, MouseButtonEventArgs e)
        {
            StartPoint = e.GetPosition(DrawingCanvas);
        }

         void buttonToolLine_MouseMove(object sender, MouseEventArgs e)
        {
            if (e.LeftButton == MouseButtonState.Pressed)
            {
                EndPoint = e.GetPosition(DrawingCanvas);
                DrawLine(StartPoint, EndPoint, DrawingCanvas);
            }
        }
         void DrawLine(Point From, Point To, Canvas TargetCanvas)
        {
            
            CurrentLine = new Line();
            CurrentLine.StrokeEndLineCap = PenLineCap.Round;
            CurrentLine.StrokeStartLineCap = PenLineCap.Round;
            CurrentLine.Stroke = Brushes.Red;
            CurrentLine.StrokeThickness = 2.0;
            CurrentLine.X1 = From.X;
            CurrentLine.Y1 = From.Y;
            CurrentLine.X2 = To.X;
            CurrentLine.Y2 = To.Y;
            Canvas.SetLeft(TargetCanvas, From.X);
            Canvas.SetTop(TargetCanvas, From.Y);
            TargetCanvas.Children.Add(CurrentLine);
        }
       
    }
}

我在这里错过了什么，当我调试时也没有击中mousedown事件，仍然是编码中的新功能，尤其是WPF和图形中的新功能，请帮助

What did I missed here, The mousedown event is also not hit when I debug, Still new in coding and specially in WPF and graphics please help

推荐答案

为什么如何注册Button的MouseDown和MouseMove事件?看来您必须注册Canvas ...

Why do you register to MouseDown and MouseMove events of the Button? It looks like you have to register to the events of the Canvas...

确定的事件，所以现在更改为

ok agreed so now changed to

<DockPanel LastChildFill="True">
        <Button Name="buttonToolLine" DockPanel.Dock="Top" Height="41" >Line</Button>
            <Canvas Name="DrawingCanvas" MouseDown="DrawingCanvas_MouseDown" MouseLeave="DrawingCanvas_MouseLeave"></Canvas>
    </DockPanel>

并且即使没有命中，代码背后的代码也发生了变化

and the code behind code also changed still the even is not hit

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