form1.cs

计算距离

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace TestLineDistance
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void textBox2_TextChanged(object sender, EventArgs e)
        {

        }

        private void textBox4_TextChanged(object sender, EventArgs e)
        {

        }

        private void textBox5_TextChanged(object sender, EventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            int h = Convert.ToInt32(x1.Text);
            int i=Convert.ToInt32(x2.Text);
            int j=Convert.ToInt32(x3.Text);
            int k=Convert.ToInt32(y1.Text);
            int l=Convert.ToInt32(y2.Text);
            int m=Convert.ToInt32(y3.Text);
            if (i == j)
            {
                int d = Math.Abs(k - l);
                richTextBox1.Text = "距离为：" + d.ToString();
            }
            if (l == m)
            {
                int d = Math.Abs(h - j);
                richTextBox1.Text = "距离为：" + d.ToString();
            }
            else 
            {
                int a = m - l;
                int b = i - j;
                int c = j * l - i * j;
                double d = Math.Abs(a * h + b * k + c) / Math.Sqrt(a * a + b * b);
                richTextBox1.Text = "距离为：" + d.ToString();
            }
            Graphics g = this.CreateGraphics();
            Pen pen = new Pen(Color.Red, 1);
            float X1 = Convert.ToSingle(x1.Text);
            float X2 = Convert.ToSingle(x2.Text);
            float Y1 = float.Parse(y1.Text);
            float Y2 = float.Parse(y2.Text);
            float X3 = float.Parse(x3.Text);
            float Y3 = float.Parse(y3.Text);
            Pen p = new Pen(Color.Black, 5);

            g.DrawLine(pen, X2, Y2, X3, Y3);
            g.DrawEllipse(p, X1, Y1, 5, 5);
        }
    }
}