c#自定义控件(1)-gdi基础

港控/mmm° 2022-09-03 01:13 194阅读 0赞

自定义控件,首先需要会使用GDI+绘制,下面是代码段基本各种常用的都有,注释也很清楚,然后工具箱中就会出现该控件

1.新建一个cs文件,继承Control`在这里插入代码片`

using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    
    namespace ControlDraw
    { 
        /// <summary>
        /// 自定义控件
        /// </summary>
        class MyControl :Control/*1.这里需要继承Control基类*/
        { 
            public MyControl()
            { 
                //两种设定颜色的方式
                this.BackColor = Color.White;            
                this.BackColor = Color.FromArgb(255, 255, 255);
                //控件的大小
                this.Size = new Size(100, 100);
            }
    
            protected override void OnPaint(PaintEventArgs e)
            { 
                //**描边的时候先使用brush涂色,在使用pen描边会避免上下边宽度不一样
                //调用父类
                base.OnPaint(e);
    
                //定义一个画布
                Graphics g = e.Graphics;
    
                //平滑模式
                g.SmoothingMode = SmoothingMode.HighQuality;
                //定义画笔,5.0f 为画笔的宽度
                Pen pen = new Pen(Color.Red,5.0f);
    
                //自定义颜色 120代表的是透明度
                Color color = Color.FromArgb(120, 255, 0, 0);
                //定义刷子
                Brush brush = new SolidBrush(Color.Blue);
    
                //画圆
                g.DrawEllipse(pen, 0, 0, 100, 100);
                //画矩形
                g.DrawRectangle(pen, 0, 0, 30, 30);
                //填充
                e.Graphics.FillEllipse(brush, 0, 0, 100, 100);
    
                //还可以使用using写法,自动释放资源
                using (Brush brush1 = new SolidBrush(Color.Red))
                { 
                    g.FillRectangle(brush, 0, 0, 100, 100);
                }
    
                #region 矩形缩放
                Rectangle rectangle = new Rectangle(0, 0, 100, 100);
                using (Pen p1 = new Pen(Color.Yellow, 5.0f))
                { 
    
                    //矩形向里缩放的距离,然后画椭圆
                    rectangle.Inflate(10, 10);
                    g.DrawEllipse(p1, rectangle);
                }
                #endregion
                pen.Dispose();
                g.Dispose();
            }
            //绘制背景色,背景色一般是不会改变的
            protected override void OnPaintBackground(PaintEventArgs pevent)
            { 
                base.OnPaintBackground(pevent);
                Graphics g = pevent.Graphics;
                int w = this.Width, h = this.Height;
                Rectangle rect = new Rectangle(0, 0, w, h);
                //渐变色
                Brush lgbrush = new LinearGradientBrush(new Point(rect.Left, rect.Top)/*左上角*/,
                    new Point(rect.Right, rect.Bottom),
                    Color.FromArgb(255, 0, 0),
                    Color.FromArgb(255, 255, 255)
                    );
                using (lgbrush)
                { 
                    g.FillRectangle(lgbrush, rect);
                }
            }
        }
    }

如果工具箱中没有该控件,则需要进行以下设置  
![如果自定义控件在工具箱里面没有的话可以在这里设置][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkYzg1OTY_size_16_color_FFFFFF_t_70]  
效果图:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkYzg1OTY_size_16_color_FFFFFF_t_70 1]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkYzg1OTY_size_16_color_FFFFFF_t_70]: /images/20220829/c1e09a3510984671851de0cc1eeb051c.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2NkYzg1OTY_size_16_color_FFFFFF_t_70 1]: /images/20220829/aad11fa310664f5595164a4ff99a984c.png