在面板C＃表單上繪制矩形

Question

問題：如何在面板而不是窗體上繪制矩形。 這是我的代碼：

 /* 
  * based on a some flags i determine which shape i want to draw. 
  * All shapes are stored in a list. I loop through the list 
  * and call each shape specific draw method - as shown below:.
  *
  */
namespace myDrawProgram
{
     private void panelArea_Paint(object sender, PaintEventArgs e)
        {
            if (drawWithPaint == true)
            {
                Pen p = new Pen(Color.Blue);
                p.DashStyle = System.Drawing.Drawing2D.DashStyle.Dash;

                if (IsShapeRectangle == true)
                {
                    e.Graphics.DrawRectangle(p, rect);
                }
                else if (IsShapeCircle == true)
                {
                    e.Graphics.DrawEllipse(p, rect);
                }

            }
            foreach (Shapes shape in listOfShapes)
            {

                shape.Draw(e.Graphics);
            }
        }
}

/*
 * In another file i have my class which deals with 
 * drawing rectangles. It is as follows: 
 *
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using SETPaint; 

namespace myDrawProgram
{
    class TheRectangles : Shapes
    {
        public Rectangle MyRect { set; get; }

        public TheRectangles(Rectangle rect, Color colour, Color boarderColour, Int32 brushThickness)
            : base(colour, boarderColour, brushThickness)
        {
            MyRect = rect;

        }


        public override void Draw(Graphics g)
        {
            base.Draw(g);


            g.FillRectangle(new SolidBrush(Shapes.c), MyRect);
            g.DrawRectangle(new Pen(bc, MyBrushThickness), MyRect);
        }
    }
}

我假設我需要做這樣的事情：

使用（圖形g = this.panel1.CreateGraphics（））{}

我只是不確定如何根據我的代碼實現這一點...

Answer 1

聽起來您還沒有掛上面板的繪畫事件：

panelArea.Paint += new PaintEventHandler(panelArea_Paint);

如果panelArea是表單的名稱，則只需將其更改為面板：

panel1.Paint += new PaintEventHandler(panel1_Paint);

然后將繪畫邏輯移至該方法：

private void panel1_Paint(object sender, PaintEventArgs e) {
  // the rest of your drawing
}

Answer 2

看起來父級（窗體？）負責繪制其每個控件。

我不會那樣做。

如果您只需要一個繪制形狀的控件（並不一定需要面板的其他行為），我將創建一個用戶控件，該控件具有一個屬性，該屬性指示要繪制的形狀並使其負責自己的渲染。

如果確實需要面板的行為，則可以將Panel子類化，並在子類控件中實現繪圖行為。 同樣，這使控件對其自己的呈現負責。

有關用戶繪制控件的信息，請參見

http://msdn.microsoft.com/en-us/library/b818z6z6(v=vs.71).aspx