在C＃中使用鼠标单击画框上画线 [英] Draw lines on a picturebox using mouse clicks in C#

问题描述

我正在尝试制作一个程序，它将在 picturebox ，使用鼠标点击该线条的绘制位置。这是我现在的代码：

pre $ $ code public partial class Form1：Form
{
int Drawshape;

私人点p1，p2;
列表< Point> p1List = new List< Point>（）;
列表< Point> p2List = new List< Point>（）;

public Form1（）
{
InitializeComponent（）;
pictureBox1.Image = new Bitmap（pictureBox1.Width，pictureBox1.Height）;


private void button1_Click（object sender，EventArgs e）
{
Drawshape = 1;
}

private void button2_Click（object sender，EventArgs e）
{
Drawshape = 2;

$ b private void pictureBox1_MouseDown（object sender，MouseEventArgs e）
{
if（Drawshape == 1）
{
if（ p1.X == 0）
{
p1.X = eX;
p1.Y = e.Y;
}
else
{
p2.X = e.X;
p2.Y = e.Y;

p1List.Add（p1）;
p2List.Add（p2）;

Invalidate（）;
p1.X = 0;



$ b private void pictureBox1_Paint（object sender，PaintEventArgs e）
{
Graphics G = Graphics.FromImage（pictureBox1 。图片）;
if（Drawshape == 1）
{
using（var p = new Pen（Color.Blue，4））
{
for（int x = 0 ; x {
G.DrawLine（p，p1List [x]，p2List [x]）;




code

那一刻它不允许我在画箱上画画。

解决方案

更改 Invalidate（）; to pictureBox1.Invalidate（）;

I'm trying to make a program that will draw lines over a picturebox using mouse clicks for the locations of where the line is to be drawn from and to. This is my current code:

public partial class Form1 : Form
{
    int Drawshape;

    private Point p1, p2;
    List<Point> p1List = new List<Point>();
    List<Point> p2List = new List<Point>();

    public Form1()
    {
        InitializeComponent();
        pictureBox1.Image = new Bitmap(pictureBox1.Width, pictureBox1.Height);
    }

    private void button1_Click(object sender, EventArgs e)
    {
        Drawshape = 1;
    }

    private void button2_Click(object sender, EventArgs e)
    {
        Drawshape = 2;
    }

    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        if (Drawshape == 1)
        {
            if (p1.X == 0)
            {
                p1.X = e.X;
                p1.Y = e.Y;
            }
            else
            {
                p2.X = e.X;
                p2.Y = e.Y;

                p1List.Add(p1);
                p2List.Add(p2);

                Invalidate();
                p1.X = 0;
            }
        }
    }

    private void pictureBox1_Paint(object sender, PaintEventArgs e)
    {
        Graphics G = Graphics.FromImage(pictureBox1.Image);
        if (Drawshape == 1)
        {
            using (var p = new Pen(Color.Blue, 4))
            {
                for (int x = 0; x < p1List.Count; x++)
                {
                    G.DrawLine(p, p1List[x], p2List[x]);
                }
            }
        }
    }

At the moment it doesn't allow me to draw on the picturebox at all. How would that be possible?

解决方案

Change Invalidate(); to pictureBox1.Invalidate();

这篇关于在C＃中使用鼠标单击画框上画线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！