C#

ctrlP = ctrl.Parent;

Rectangle r = ctrl.Bounds;

Rectangle rP = new Rectangle(0, 0, ctrlP.Width, ctrlP.Height);
r.Intersect(rP);

Graphics g = ctrlP.CreateGraphics();

Pen p = new Pen(Color.Red);
p.Width = 1.5f;

g.DrawRectangle(p, r);
g.Dispose();

Rob Philpott wrote:

The right and bottom line are probably not appearing because they're outside the clip rectangle

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

namespace draw
{
    public partial class Form1 : Form
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.panel1 = new System.Windows.Forms.Panel();
            this.groupBox1 = new System.Windows.Forms.GroupBox();
            this.panel1.SuspendLayout();
            this.SuspendLayout();
            // 
            // panel1
            // 
            this.panel1.Controls.Add(this.groupBox1);
            this.panel1.Location = new System.Drawing.Point(192, 141);
            this.panel1.Name = "panel1";
            this.panel1.Size = new System.Drawing.Size(200, 100);
            this.panel1.TabIndex = 0;
            // 
            // groupBox1
            // 
            this.groupBox1.Location = new System.Drawing.Point(91, 43);
            this.groupBox1.Name = "groupBox1";
            this.groupBox1.Size = new System.Drawing.Size(200, 100);
            this.groupBox1.TabIndex = 0;
            this.groupBox1.TabStop = false;
            this.groupBox1.Text = "groupBox1";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(674, 358);
            this.Controls.Add(this.panel1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
            this.panel1.ResumeLayout(false);
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.Panel panel1;
        private System.Windows.Forms.GroupBox groupBox1;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Paint(object sender, PaintEventArgs e)
        {
            Control ctrl = groupBox1;
            Control ctrlP;

            ctrlP = ctrl.Parent;
            Rectangle r = ctrl.Bounds;
            Rectangle rP = new Rectangle(0, 0, ctrlP.Width, ctrlP.Height);
            r.Intersect(rP);
            r.Inflate(-2, -2);

            Graphics g = ctrlP.CreateGraphics();
            Pen p = new Pen(Color.Red);
            p.Width = 1.5f;
            g.DrawRectangle(p, r);
            g.Dispose();
        }
    }
}

cppwxwidgetsss wrote:

I want to know is it better to have a GDI+ and/or have a System.Drawing or/and
it is better to have a custom Control

hwswin wrote:

It's not a easy thing,right?