设计属性包括：
外环宽度，外环间隙，内环间隙，颜色【五种】，当前值。
由于该LED指示灯基本是完全独立设计的，并不是在某个控件的基础上进行的开发，因此，这里使
用用户控件的方式进行开发。通过GDI+方式对控件进行绘制。GDI的坐标系如下：
首先绘制外环，然后绘制内圆。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms; namespace JSControl
{
public partial class LedControl : UserControl
{
public LedControl()
{
InitializeComponent();
this.Size = new Size(40,40);//初始化控件大小
} #region Filed
private float outWidth = 4.0f;
[Browsable(true)]
[Category("自定义属性")]
[Description("外环宽度")]
public float OutWidth
{
get { return outWidth; }
set
{
if (value <= 0 || value > 0.1f * this.Width)
{
return;
}
outWidth = value;
this.Invalidate();
}
} private float outGap = 3.0f;
[Browsable(true)]
[Category("自定义属性")]
[Description("外环间隙")]
public float OutGap
{
get { return outGap; }
set
{
if (value <= 0 || value > 0.1f * this.Width || inGap <= value)
{
return;
}
outGap = value; this.Invalidate();
}
} private float inGap = 8.0f;
[Browsable(true)]
[Category("自定义属性")]
[Description("内环间隙")]
public float InGap
{
get { return inGap; }
set
{
if (value <= 0 || value <= outGap)
{
return;
}
inGap = value;
this.Invalidate();
}
} private Color color1 = Color.Gray;
[Browsable(true)]
[Category("自定义属性")]
[Description("指示灯颜色")]
public Color Color1
{
get { return color1; }
set
{
color1 = value;
this.Invalidate();
}
} private Color color2 = Color.LimeGreen;
[Browsable(true)]
[Category("自定义属性")]
[Description("LimeGreen")]
public Color Color2
{
get { return color2; }
set
{
color2 = value;
this.Invalidate();
}
} private Color color3 = Color.Red;
[Browsable(true)]
[Category("自定义属性")]
[Description("Red")]
public Color Color3
{
get { return color3; }
set
{
color3 = value;
this.Invalidate();
}
} private Color color4 = Color.DarkGoldenrod;
[Browsable(true)]
[Category("自定义属性")]
[Description("DarkGoldenrod")]
public Color Color4
{
get { return color4; }
set
{
color4 = value;
this.Invalidate();
}
} private Color color5 = Color.Blue;
[Browsable(true)]
[Category("自定义属性")]
[Description("Blue")]
public Color Color5
{
get { return color5; }
set
{
color5 = value;
this.Invalidate();
}
} //指示灯颜色索引
private int currentValue = 0;
[Browsable(true)]
[Category("自定义属性")]
[Description("当前值")]
public int CurrentValue
{
get { return currentValue; }
set
{
if (value > 4 || value < 0)
{
return;
}
currentValue = value;
this.Invalidate();
}
}
#endregion #region verride
private Graphics g; private Pen p;//画笔 private SolidBrush sb;//画刷 private int width;//控件宽度 private int height;//控件高度 protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
g = e.Graphics;
width = this.Width;
height = this.Height;
//这里是为了设置渲染效果，消除锯齿，高效果显示
g.TextRenderingHint = System.Drawing.Text.TextRenderingHint.ClearTypeGridFit;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;
g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
if (inGap>0.5f*this.Height||inGap>0.5f*this.Width)
{
return;
}
Color CurrentColor = GetCurrentColor(this.currentValue);
//设置画笔的宽度
p = new Pen(CurrentColor, outWidth);
//先绘制外环
RectangleF rec = new RectangleF(outGap, outGap, this.width - 2 * outGap, this.height - 2 * outGap);
g.DrawEllipse(p, rec);
sb = new SolidBrush(CurrentColor);
//再绘制内圆
rec = new RectangleF(inGap, inGap, this.width - 2 * inGap, this.height - 2 * inGap);
g.FillEllipse(sb, rec); }
#endregion #region Private Methods
/// <summary>
/// 设置控件颜色
/// </summary>
/// <returns></returns>
private Color GetCurrentColor(int currentColor)
{
List<Color> ColorList = new List<Color>();
ColorList.Add(color1);
ColorList.Add(color2);
ColorList.Add(color3);
ColorList.Add(color4);
ColorList.Add(color5);
return ColorList[currentValue];
} #endregion
}
}
this.Invalidate()表示进行重绘，调用它后将会执行
protected override void OnPaint(PaintEventArgs e)｛｝中的代码进行重绘。
生成后，将和其他控件一样可以看到其属性。
