Question

我想在表单上绘制一个多边形，但我想通过鼠标点击添加多边形位置。

现在我给了常量（x，y）位置并且它返回了一个多边形，但是我想通过点击鼠标来添加这些位置。

 Point[] po = new Point[]
            {

                new Point {X=15, Y=51},
                new Point {X=40, Y= 13},
                new Point {X=87, Y= 53},
                new Point {X=56, Y= 87},
                new Point {X=44, Y= 32},
            };

Answer 1

为绘制多边形创建自定义控件：

using System.Collections.ObjectModel;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;

namespace WindowsFormsApplication4
{
public partial class DrawPolygon : Control
{
    ObservableCollection<PointF> points;
    public int SideCount
    {
        get { return sideCount; }
        set { sideCount = value; }
    }

    public DrawPolygon()
    {
        InitializeComponent();
        points = new ObservableCollection<PointF>();
        points.CollectionChanged += Points_CollectionChanged;
    }

    private void Points_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
    {
        if (e.Action == System.Collections.Specialized.NotifyCollectionChangedAction.Add)
        if (points.Count >= sideCount)
            {
                points = new ObservableCollection<PointF>(points.Skip(points.Count - sideCount));
                points.CollectionChanged += Points_CollectionChanged;
            }
        Refresh();
    }
    protected override void OnMouseClick(MouseEventArgs e)
    {
        base.OnMouseClick(e);
        points.Add(e.Location);
    }

    protected override void OnPaint(PaintEventArgs pe)
    {
        base.OnPaint(pe);
        if (points.Count > 1)
            pe.Graphics.DrawPolygon(Pens.Aqua, points.ToArray());

    }
}

}

构建完成后，您可以将其从工具箱添加到表单中。

这是结果的示例：Polygon

在表单上绘制多边形

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