2.C#Panel扩展控件

1.解决方案下添加新建项目新建类库

2. 在项目下添加新建项选择新建组件类

3.先引用，然后导入两个命名空间

4.因为是扩展控件，把继承自Component改成继承自Panel

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;

using System.Linq;
using System.Security.Principal;
using System.Text;
using System.Windows.Forms;
using System.Drawing.Drawing2D;
using System.Drawing.Text;
using System.Drawing;
namespace FJZControl
{
    public partial class FJZPanel : Panel
    {
        public FJZPanel()
        {
            InitializeComponent();
        }

        public FJZPanel(IContainer container)
        {
            container.Add(this);

            InitializeComponent();
        }
        #region 属性
        private Color headBackColor = Color.LimeGreen;
        [Category("我的自定义Panel控件属性")]
        [Description("标题的背景颜色")]
        public Color HeadBackColor
        {
            get
            {
                return headBackColor;
            }

            set
            {
                headBackColor = value;

                this.Invalidate();
            }
        }

        private Color headForeColor = Color.Black;
        [Category("我的自定义Panel控件属性")]
        [Description("标题的背景颜色")]
        public Color HeadForeColor
        {
            get
            {
                return headForeColor;
            }

            set
            {
                headForeColor = value;

                this.Invalidate();
            }
        }


        private int headHeight = 30;
        [Category("我的自定义Panel控件属性")]
        [Description("标题的高度")]
        public int HeadHeight
        {
            get
            {
                return headHeight;
            }

            set
            {
                headHeight = value;
                this.Invalidate();
            }
        }

        private string headText = "标题名称";
        [Category("我的自定义Panel控件属性")]
        [Description("标题的名称")]
        public string HeadText
        {
            get { return headText; }
            set
            {
                this.headText = value;
                this.Invalidate();
            }
            
        }



        private float linearScale=0.4f;
        [Category("我的自定义Panel控件属性")]
        [Description("渐变程度")]
        public float LinearScale
        {
            get
            {
                return linearScale;
            }

            set
            {
                linearScale = value;
                this.Invalidate();
            }
        }
        #endregion

        #region 字段
        Graphics g;
        Pen p;
        SolidBrush sb;
        #endregion
        #region 方法
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            //自定义绘制过程

            //获取这个画布
             g = e.Graphics;

            //设置画布
            SetGrahics();

            //第一步:画标题框
            using (LinearGradientBrush brush = new LinearGradientBrush(new PointF(0, 0), new PointF(0, this.headHeight), GetStartLinearColor(this.headBackColor), this.headBackColor))
            {
                g.FillRectangle(brush, new RectangleF(0, 0, this.Width, this.headHeight));
            }
            //第二步:标题
            StringFormat sf = new StringFormat();
            sf.Alignment = StringAlignment.Center;
            sf.LineAlignment = StringAlignment.Center;
            using(SolidBrush sb=new SolidBrush(this.headForeColor))
            {
                g.DrawString(this.headText, this.Font, sb,new RectangleF( 0,0,this.Width, this.headHeight), sf);
            }
            //第三步:画边框
            using(Pen p=new Pen(this.headBackColor))
            {
                g.DrawRectangle(p, 0, 0, this.Width-1, this.Height-1);
                g.DrawLine(p, 0, this.HeadHeight, this.Width - 1, this.headHeight - 1);
            }
        }
        //设置画布属性
        private void SetGrahics()
        {
            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.SmoothingMode = SmoothingMode.HighQuality;

            g.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;
            g.TextRenderingHint = TextRenderingHint.AntiAlias;

        }

        //获取
        private Color GetStartLinearColor(Color EndLinearColor)
        {
            return Color.FromArgb((int)(EndLinearColor.R + (255 - EndLinearColor.R) * this.linearScale), (int)(EndLinearColor.G + (255 - EndLinearColor.G) * this.linearScale), (int)(EndLinearColor.B + (255 - EndLinearColor.B) * this.linearScale));
        }
        #endregion
    }
}

效果如下：