winform滚动条美化-Panel

      查阅网上关于滚动条的美化资料，多数不符合我的要求；打算动手自己撸一个；最终实现效果如下图：

实现方式为隐藏系统滚动条，设置控件工作区域，把自定义滚动条放到对应的位置实现滚动操作；后面会一步步的实现该功能；

参考资料包含不限于：

C#程序员开发WinForm必须知道的 Window 消息大全-阿里云开发者社区

首先是自定义滚动条的实现

1.创建滚动条控件继承Control

2.添加一些必要的属性：滚动条最大值、背景色、滑块颜色等等

3.绘制自己想要的样式并添加行为事件

绘制滑块圆角代码

1.  
   private void DrawSlider(Graphics g)
2.  
   {
3.  
   GraphicsPath path;
4.  
   if (rectSlider.Width == 0 || rectSlider.Height == 0)
5.  
   {
6.  
   return;
7.  
   }
8.  
   if (rectSlider.Width > rectSlider.Height)
9.  
   {
10.  
    //水平
11.  
    path = DrawHelper.GetHorizontal(this.rectSlider);
12.  
    }
13.  
    else
14.  
    {
15.  
    //垂直
16.  
    path = DrawHelper.GetVertical(this.rectSlider);
17.  
    }
18.  
     
19.  
    using (SolidBrush sb = new SolidBrush(SliderColor))
20.  
    {
21.  
    g.FillPath(sb, path);
22.  
    }
23.  
    path.Dispose();
24.  
     
25.  
    }

重新鼠标按下（OnMouseDown）抬起（OnMouseUp）和移动（OnMouseMove）的事件来实现我们需要完成的操作，需要记录鼠标按下的点处理移动距离；触发事件的时机可自行调整；

展示代码为demo示例，存在很大优化空间

1.  
   public class VSliderControl : Control
2.  
   {
3.  
   protected override CreateParams CreateParams
4.  
   {
5.  
   get
6.  
   {
7.  
   CreateParams cp = base.CreateParams;
8.  
   cp.ExStyle &= ~0x02000000;
9.  
   return cp;
10.  
    }
11.  
    }
12.  
     
13.  
    private int yLocation;
14.  
    private bool isMouseDown = false;
15.  
    private float movePix = 0;
16.  
    //最大值
17.  
    private double maxPos = 100;
18.  
    //当前位置
19.  
    private int pos = 1;
20.  
    public int Pos
21.  
    {
22.  
    get { return pos; }
23.  
    set
24.  
    {
25.  
    if (value > maxPos||value<0)
26.  
    { return; }
27.  
    pos = value;
28.  
    SetMovePix();
29.  
    this.Invalidate();
30.  
    }
31.  
    }
32.  
    //平均1 Pos多少像素
33.  
    private double avePos = 1;
34.  
     
35.  
    public new event EventHandler Scroll = null;
36.  
     
37.  
    //滑块大小
38.  
    private RectangleF rectSlider;
39.  
     
40.  
    private Color sliderColor;
41.  
    public Color SliderColor { get => sliderColor; set => sliderColor = value; }
42.  
     
43.  
     
44.  
     
45.  
    public double MaxPos
46.  
    {
47.  
    get { return maxPos; }
48.  
    set
49.  
    {
50.  
    if (maxPos != value)
51.  
    {
52.  
    maxPos = value;
53.  
    this.AutoCalcSize();
54.  
    }
55.  
    }
56.  
    }
57.  
     
58.  
     
59.  
    public VSliderControl()
60.  
    {
61.  
    this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
62.  
    this.SetStyle(ControlStyles.DoubleBuffer, true);
63.  
    this.SetStyle(ControlStyles.ResizeRedraw, true);
64.  
    this.SetStyle(ControlStyles.Selectable, true);
65.  
    this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
66.  
    this.SetStyle(ControlStyles.UserPaint, true);
67.  
    }
68.  
    protected override void OnPaint(PaintEventArgs e)
69.  
    {
70.  
     
71.  
    base.OnPaint(e);
72.  
     
73.  
    Graphics g = e.Graphics;
74.  
    g.SetGDIHigh();
75.  
     
76.  
    DrawSlider(g);
77.  
     
78.  
     
79.  
    }
80.  
    protected override void OnMouseDown(MouseEventArgs e)
81.  
    {
82.  
    base.OnMouseDown(e);
83.  
    if (rectSlider.Contains(e.Location))
84.  
    {
85.  
    isMouseDown = true;
86.  
    yLocation = e.Y;
87.  
    }
88.  
    }
89.  
    protected override void OnMouseMove(MouseEventArgs e)
90.  
    {
91.  
    base.OnMouseMove(e);
92.  
    if (isMouseDown)
93.  
    {
94.  
    int mY = (e.Y - yLocation);
95.  
    if (mY rectSlider.Height rectSlider.Y > this.Height)
96.  
    {
97.  
    movePix = this.Height - rectSlider.Height - rectSlider.Y;
98.  
     
99.  
    }
100.  
     else if (mY rectSlider.Y < -1)
101.  
     {
102.  
     movePix = - rectSlider.Y;
103.  
     }
104.  
     else
105.  
     if (mY != 0)
106.  
     {
107.  
     yLocation = e.Y;
108.  
     movePix = mY;
109.  
     }
110.  
     PixToPos();
111.  
     AutoCalcSize();
112.  
     Scroll?.Invoke(this, new EventArgs());
113.  
     }
114.  
     }
115.  
     protected override void OnMouseUp(MouseEventArgs e)
116.  
     {
117.  
     base.OnMouseUp(e);
118.  
     isMouseDown = false;
119.  
      
120.  
     }
121.  
      
122.  
     protected override void OnClientSizeChanged(EventArgs e)
123.  
     {
124.  
     base.OnClientSizeChanged(e);
125.  
     AutoCalcSize();
126.  
     }
127.  
     private void AutoCalcSize()
128.  
     {
129.  
     double sliderL = this.Height / maxPos * this.Height;
130.  
     double pix = (this.Height ) / (maxPos - this.Height);
131.  
     if (double.IsNaN( sliderL )|| sliderL == 0)
132.  
     return;
133.  
      
134.  
      
135.  
     float y = movePix rectSlider.Y;
136.  
     int h = Convert.ToInt32(sliderL);
137.  
     rectSlider.X = -0.5f;
138.  
     rectSlider.Y = y;
139.  
     rectSlider.Width = this.Width ;
140.  
     rectSlider.Height = h;
141.  
     avePos = pix;
142.  
     this.Invalidate();
143.  
     movePix = 0;
144.  
     }
145.  
      
146.  
     private void SetMovePix()
147.  
     {
148.  
     double sliderL = this.Height / maxPos * this.Height;
149.  
     double pix = (this.Height- sliderL) *pos/ (maxPos - this.Height);
150.  
     rectSlider.Y = float.Parse( pix.ToString("0.00"));
151.  
     movePix = 0;
152.  
     }
153.  
     private void PixToPos()
154.  
     {
155.  
     double sliderL = this.Height / maxPos * this.Height;
156.  
     double pix = (maxPos - this.Height)/(this.Height - sliderL) *rectSlider.Y;
157.  
     pos = Convert.ToInt32(Math.Ceiling(pix));
158.  
     }
159.  
     private void DrawSlider(Graphics g)
160.  
     {
161.  
     GraphicsPath path;
162.  
     if (rectSlider.Width == 0 || rectSlider.Height == 0)
163.  
     {
164.  
     return;
165.  
     }
166.  
     if (rectSlider.Width > rectSlider.Height)
167.  
     {
168.  
     //水平
169.  
     path = DrawHelper.GetHorizontal(this.rectSlider);
170.  
     }
171.  
     else
172.  
     {
173.  
     //垂直
174.  
     path = DrawHelper.GetVertical(this.rectSlider);
175.  
     }
176.  
      
177.  
     using (SolidBrush sb = new SolidBrush(SliderColor))
178.  
     {
179.  
     g.FillPath(sb, path);
180.  
     }
181.  
     path.Dispose();
182.  
      
183.  
     }
184.  
      
185.  
     }

未完成待续

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