custombutton.cs

csharp课本的源代码

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

namespace CustomWinControls
{
    public partial class CustomButton : Control
    {
        private Rectangle clickRectangleValue = new Rectangle();
        private PushButtonState state = PushButtonState.Normal;

        public CustomButton()
        {
            this.Width = 100;
            this.Height = 40;
            InitializeComponent();
            
        }

        //定义单击按钮后的小按钮矩形边界
        public Rectangle ClickRectangle
        {
            get
            {
                clickRectangleValue.X = ClientRectangle.X +
                    (int)(.2 * ClientRectangle.Width);
                clickRectangleValue.Y = ClientRectangle.Y +
                    (int)(.2 * ClientRectangle.Height);
                clickRectangleValue.Width = ClientRectangle.Width -
                    (int)(.4 * ClientRectangle.Width);
                clickRectangleValue.Height = ClientRectangle.Height -
                    (int)(.4 * ClientRectangle.Height);

                return clickRectangleValue;
            }
        }

        // Draw the large or small button, depending on the current state.
        protected override void OnPaint(PaintEventArgs pe)
        {
            base.OnPaint(pe);
            
            // 如果按钮被按下去，则绘制小的按钮图形界面
            if (state == PushButtonState.Pressed)
            {
                //Application.RenderWithVisualStyles属性获取当前应用程序
                //是否使用可视样式绘制控件；当未启动时，设置为其父级的背景色
                this.BackColor = Application.RenderWithVisualStyles ?
                    Color.Azure : this.Parent.BackColor;

                //变为小按钮后，原按钮的一部分将显现出来，
                //需要调用DrawParentBackground方法重新绘制
                //使其变为父级的背景。
                ButtonRenderer.DrawParentBackground(pe.Graphics, ClientRectangle, this);
                ButtonRenderer.DrawButton(pe.Graphics, ClickRectangle,
                    this.Text, this.Font, true, state);
            }
            //绘制大的未被按下去的按钮图形界面
            else
            {
                ButtonRenderer.DrawButton(pe.Graphics, ClientRectangle, this.Text, this.Font, false, state);
               
            }
        }

        // Draw the smaller pressed button image.
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            state = PushButtonState.Pressed;
            Invalidate();
        }

        // Draw the button in the hot state. 
        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);
            //设置按钮状态为激活状态
            state = PushButtonState.Hot;
            Invalidate();
        }

        // Draw the button in the unpressed state.
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);
            state = PushButtonState.Normal;
            Invalidate();
        }

        // Draw the button hot if the mouse is released on the button. 
        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            OnMouseEnter(e);
        }

        // Detect when the cursor leaves the button area while 
        // it is pressed.
        protected override void OnMouseMove(MouseEventArgs e)
        {
            base.OnMouseMove(e);

            // 鼠标左键按下并且光标从按下的按钮上离开时，   
            // 恢复按钮的正常外观。
            if ((e.Button & MouseButtons.Left) == MouseButtons.Left &&
                !ClientRectangle.Contains(e.Location) &&
                state == PushButtonState.Pressed)
            {
                OnMouseLeave(e);
            }
        }

    }
}