ellipsebutton.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 CustomWinControls;
using System.Drawing.Drawing2D;
using System.Windows.Forms.VisualStyles;

namespace ExtensibleControls
{
    public partial class EllipseButton : CustomButton
    {
        private PushButtonState state = PushButtonState.Normal;
        private Color startColor = Color.White; //渐变起始色 
        private Color endColor = Color.Red;     //渐变终止色 
        private Rectangle rect = new Rectangle();

        [Description("设定渐变的起始色"), Category("Appearance")]
        public Color StartColor
        {
            get
            {
                return startColor;
            }
            set
            {
                startColor = value;
                OnPaint(new PaintEventArgs(this.CreateGraphics(), ClientRectangle));
            }
        }
        [Description("设定渐变的终止色"), Category("Appearance")]
        public Color EndColor
        {
            get
            {
                return endColor;
            }
            set
            {
                endColor = value;
                OnPaint(new PaintEventArgs(this.CreateGraphics(), ClientRectangle));
            }
        }

        public EllipseButton()
        {
            InitializeComponent();
        }

        protected override void OnPaint(PaintEventArgs pe)
        {
            // 调用基类 OnPaint
            base.OnPaint(pe);

            pe.Graphics.SmoothingMode = SmoothingMode.AntiAlias;
            pe.Graphics.Clear(this.BackColor);
            rect = (state == PushButtonState.Pressed) ? this.ClickRectangle : this.ClientRectangle;
            LinearGradientBrush myBrush = new LinearGradientBrush(rect, StartColor, EndColor, LinearGradientMode.ForwardDiagonal);
            ButtonRenderer.DrawParentBackground(pe.Graphics, ClientRectangle, this);
            pe.Graphics.FillEllipse(myBrush, rect);
            myBrush.Dispose();
            StringFormat alignFormat = new StringFormat();
            alignFormat.LineAlignment = StringAlignment.Center;
            alignFormat.Alignment = StringAlignment.Center;
            pe.Graphics.DrawString(this.Text, this.Font, new SolidBrush(this.ForeColor), rect, alignFormat);
        }
        protected override void OnMouseDown(MouseEventArgs e)
        {
            base.OnMouseDown(e);
            //设置按钮视觉状态为按下状态
            state = PushButtonState.Pressed;
            Invalidate();
        }
        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);
            //设置按钮状态为激活状态
            state = PushButtonState.Hot;
            Invalidate();
        }
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);
            state = PushButtonState.Normal;
            Invalidate();
        }
        protected override void OnMouseUp(MouseEventArgs e)
        {
            base.OnMouseUp(e);
            OnMouseEnter(e);
        }
        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);
            }
        }
        protected override void OnTextChanged(EventArgs e)
        {
            OnPaint(new PaintEventArgs(this.CreateGraphics(), ClientRectangle));
        }


    }
}