GIS作业01

创建工程

创建一个Windows窗体应用程序项目
如下图:

创建好后即可进入项目主界面

创建基本类

右键你的项目名称如下图:

选择添加，新建项进入新建界面

选择代码文件类型，并修改名称

编写代码

进入创建的代码文件编辑界面粘贴代码:

namespace MyGIS
{
    class GISVertex
    {
        public double x;
        public double y;
    }

    class GISPoint
    {
        public GISVertex Location;
        public string Attribute;
    }
    class GISLine
    {
        List<GISVertex> AllVertexs;
    }

    class GISPolygon
    {
        List<GISVertex> AllVertexs;
    }
}

会有报红提示，因为没有导入类

添加GISVertex GISPoint类

重复前面操作(即新建代码文件)，
我们先添加GISVertex类
代码:

using System;

class GISVertex
{
    public double x;
    public double y;

    public GISVertex(double _x, double _y)
    {
        x = _x;
        y = _y;
    }

    public double Distance(GISVertex anothervertex)
    {
        return Math.Sqrt((x - anothervertex.x) * (x - anothervertex.x) + (y - anothervertex.y) * (y - anothervertex.y));
    }
}

同理创建GISPoint类

using System.Drawing;

class GISPoint
{
    public GISVertex Location;
    public string Attribute;

    public GISPoint(GISVertex onevertex, string onestring)
    {
        Location = onevertex;
        Attribute = onestring;
    }

    public void DrawPoint(Graphics graphics)
    {
        graphics.FillEllipse(new SolidBrush(Color.Red), new Rectangle((int)(Location.x) - 3, (int)(Location.y) - 3, 6, 6));
    }

    public void DrawAttribute(Graphics graphics)
    {
        graphics.DrawString(Attribute, new Font("宋体", 20), new SolidBrush(Color.Green), new PointF((int)(Location.x), (int)(Location.y)));
    }

    public double Distance(GISVertex anothervertex)
    {
        return Location.Distance(anothervertex);
    }
}

窗体设计视图

切换到form1设计界面如下图:

通过左侧的工具箱，公开控件即可添加控件到窗体上如下图:

点击控件，在右下角修改名字

修改名字后效果:

编辑窗体代码

双击进入form1代码编辑界面

界面如下:

添加代码:

List<GISPoint> points = new List<GISPoint>();

添加按钮事件代码

切换到form1主界面，双击按钮进入代码编辑页面

界面如下:

在方法添加代码:

    double x = Convert.ToDouble(textBox1.Text);
    double y = Convert.ToDouble(textBox2.Text);
    string attribute = textBox3.Text;
    GISVertex onevertex = new GISVertex(x, y);
    GISPoint onepoint = new GISPoint(onevertex, attribute);
    Graphics graphics = this.CreateGraphics();
    onepoint.DrawPoint(graphics);
    onepoint.DrawAttribute(graphics);
    points.Add(onepoint);

添加事件

切回form1主界面点击空白处按下图操作

会生成一个鼠标点击方法:

在方法里添加代码:

GISVertex onevertex = new GISVertex((double)e.X, (double)e.Y);
    double mindistance = Double.MaxValue;
    int findid = -1;
    for (int i = 0; i < points.Count; i++)
    {
        double distance = points[i].Distance(onevertex);
        if (distance < mindistance)
        {
            mindistance = distance;
            findid = i;
        }
    }
    if (mindistance > 5 || findid == -1)
    {
        MessageBox.Show("没有点实体或者鼠标点击位置不准确！");
    }
    else
        MessageBox.Show(points[findid].Attribute);