董鹏的回答：引用命名空间： using System.Collections; 不行哈，ArrayList是System.Collections下的一个类型，而不是System.Collections.Generic下的，如果你不引用可以直接这么写： System.Collections.ArrayList = new System.Collections.ArrayList(arr); 上面得也是对的 用using System.Collections.Generic就没有把ArrayList这个类型引用进去，会报错 陈子良的回答：引用命名空间： using System.Collections; 不行哈，ArrayList是System.Collections下的一个类型，而不是System.Collections.Generic下的，如果你不引用可以直接这么写： System.Collections.ArrayList = new System.Collections.ArrayList(arr); 上面得也是对的 用using System.Collections.Generic就没有把ArrayList这个类型引用进去，会报错 刘老大的回答：using system.collections; 张玉平的回答：{ public partial class Form1 : Form { ArrayList points; Point currentPoint; Pen thepen; float penwidth; SolidBrush thebrush; private System.Windows.Forms.Button btnColor; private System.Windows.Forms.ListBox lstPenStyle; private System.Windows.Forms.CheckBox rbPen; Color thecolor; public Form1() { InitializeComponent(); currentPoint = new Point(50,10); points = new ArrayList(); points.Add(currentPoint); penwidth = 1; thecolor = Color.Black; thepen = new Pen(thecolor); thebrush = new SolidBrush(thecolor); } private void Form1_MouseUp(object sender, MouseEventArgs e) { if (currentPoint.X != e.X || currentPoint.Y != e.Y) { currentPoint.X = e.X; currentPoint.Y = e.Y; points.Add(currentPoint); this.Invalidate(); this.Update(); } } private void Form1_Paint(object sender, PaintEventArgs e) { Graphics g = e.Graphics; Point[] ps=(Point[]) points.ToArray(typeof(Point)); if (rbLine.Checked) g.DrawLine(Pens.Black, ps[0], ps[ps.Length - 1]); else if (rbRectangle.Checked) g.DrawRectangle(thepen, ps[0].X, ps[0].Y, ps[ps.Length - 1].X - ps[0].X, ps[ps.Length - 1].Y - ps[ps.Length - 1].Y); else if (rbCurve.Checked) g.DrawCurve(thepen, ps); else if (rbPolygon.Checked) g.DrawPolygon(thepen, ps); else if (rbEllipse.Checked) g.DrawEllipse(thepen,ps[0].X,ps[0].Y,ps[ps.Length-1].X-ps[0].X,ps[ps.Length-1].Y-ps[0].Y); } private void ChangeDrawType(object sender, PaintEventArgs e) { points.Clear(); currentPoint = new Point(50,10); points.Add(currentPoint); |
