官网

http://www.hzhcontrols.com

前提

入行已经7,8年了，一直想做一套漂亮点的自定义控件，于是就有了本系列文章。

GitHub：https://github.com/kwwwvagaa/NetWinformControl

码云：https://gitee.com/kwwwvagaa/net_winform_custom_control.git

如果觉得写的还行，请点个 star 支持一下吧

欢迎前来交流探讨： 企鹅群568015492 

来都来了，点个【推荐】再走吧，谢谢

NuGet

Install-Package HZH_Controls

目录

https://www.cnblogs.com/bfyx/p/11364884.html

用处及效果

准备工作

GDI+画图，不了解先百度

开始

思路：

控件扩展属性，在组件中对需要显示倒影的控件的父控件添加Paint事件，在Paint事件中绘制控件，并旋转180，然后画到父控件上，然后再覆盖一层渐变色，完美。

添加一个类ShadowComponent 继承Component，实现 IExtenderProvider接口，扩展属性

代码比较少，直接放上来了

  1 /// 

  2         /// The m control cache
  3         /// 
  4         Dictionarybool> m_controlCache = new Dictionarybool>();
  5 
  6         #region 构造函数    English:Constructor
  7         /// 

  8         /// Initializes a new instance of the  class.
  9         /// 
 10         public ShadowComponent()
 11         {
 12 
 13         }
 14 
 15         /// 

 16         /// Initializes a new instance of the  class.
 17         /// 
 18         /// The container.
 19         public ShadowComponent(IContainer container)
 20             : this()
 21         {
 22             container.Add(this);
 23         }
 24         #endregion
 25 
 26         /// 

 27         /// 指定此对象是否可以将其扩展程序属性提供给指定的对象。
 28         /// 
 29         /// 要接收扩展程序属性的 。
 30         /// 如果此对象可以扩展程序属性提供给指定对象，则为 true；否则为 false。
 31         public bool CanExtend(object extendee)
 32         {
 33             if (extendee is Control && !(extendee is Form))
 34                 return true;
 35             return false;
 36         }
 37 
 38         /// 

 39         /// Gets the show shadow.
 40         /// 
 41         /// The control.
 42         /// true if XXXX, false otherwise.
 43         [Browsable(true), Category("自定义属性"), Description("是否显示倒影"), DisplayName("ShowShadow"), Localizable(true)]
 44         public bool GetShowShadow(Control control)
 45         {
 46             if (m_controlCache.ContainsKey(control))
 47                 return m_controlCache[control];
 48             else
 49                 return false;
 50         }
 51 
 52         /// 

 53         /// Sets the show shadow.
 54         /// 
 55         /// The control.
 56         /// if set to true [is show shadow].
 57         public void SetShowShadow(Control control, bool isShowShadow)
 58         {
 59             control.ParentChanged += control_ParentChanged;
 60             m_controlCache[control] = isShowShadow;
 61         }
 62 
 63         /// 

 64         /// Handles the ParentChanged event of the control control.
 65         /// 
 66         /// The source of the event.
 67         /// The  instance containing the event data.
 68         void control_ParentChanged(object sender, EventArgs e)
 69         {
 70             Control control = sender as Control;
 71             if (control.Parent != null && m_controlCache[control])
 72             {
 73                 if (!lstPaintEventControl.Contains(control.Parent))
 74                 {
 75                     lstPaintEventControl.Add(control.Parent);
 76                     Type type = control.Parent.GetType();
 77                     System.Reflection.PropertyInfo pi = type.GetProperty("DoubleBuffered", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
 78                     pi.SetValue(control.Parent, true, null);
 79                     control.Parent.Paint += Parent_Paint;
 80                 }
 81             }
 82         }
 83 
 84         /// 

 85         /// The LST paint event control
 86         /// 
 87         List lstPaintEventControl = new List();
 88         /// 

 89         /// The shadow height
 90         /// 
 91         private float shadowHeight = 0.3f;
 92 
 93         /// 

 94         /// Gets or sets the height of the shadow.
 95         /// 
 96         /// The height of the shadow.
 97         [Browsable(true), Category("自定义属性"), Description("倒影高度，0-1"), Localizable(true)]
 98         public float ShadowHeight
 99         {
100             get { return shadowHeight; }
101             set { shadowHeight = value; }
102         }
103         /// 

104         /// The BLN loading
105         /// 
106         bool blnLoading = false;
107         /// 

108         /// Handles the Paint event of the Parent control.
109         /// 
110         /// The source of the event.
111         /// The  instance containing the event data.
112         void Parent_Paint(object sender, PaintEventArgs e)
113         {
114             if (blnLoading)
115                 return;           
116             if (shadowHeight > 0)
117             {
118                 var control = sender as Control;
119                 var lst = m_controlCache.Where(p => p.Key.Parent == control && p.Value);
120                 if (lst != null && lst.Count() > 0)
121                 {
122                     blnLoading = true;
123                     e.Graphics.SetGDIHigh();
124                     foreach (var item in lst)
125                     {
126                         Control _control = item.Key;
127 
128                         using (Bitmap bit = new Bitmap(_control.Width, _control.Height))
129                         {
130                             _control.DrawToBitmap(bit, _control.ClientRectangle);
131                             using (Bitmap bitNew = new Bitmap(bit.Width, (int)(bit.Height * shadowHeight)))
132                             {
133                                 using (var g = Graphics.FromImage(bitNew))
134                                 {
135                                     g.DrawImage(bit, new RectangleF(0, 0, bitNew.Width, bitNew.Height), new RectangleF(0, bit.Height - bit.Height * shadowHeight, bit.Width, bit.Height * shadowHeight), GraphicsUnit.Pixel);
136                                 }
137                                 bitNew.RotateFlip(RotateFlipType.Rotate180FlipNone);
138                                 e.Graphics.DrawImage(bitNew, new Point(_control.Location.X, _control.Location.Y + _control.Height + 1));
139                                 Color bgColor = GetParentColor(_control);
140                                 LinearGradientBrush lgb = new LinearGradientBrush(new Rectangle(_control.Location.X, _control.Location.Y + _control.Height + 1, bitNew.Width, bitNew.Height), Color.FromArgb(50, bgColor), bgColor, 90f);   //75f 表示角度
141                                 e.Graphics.FillRectangle(lgb, new Rectangle(new Point(_control.Location.X, _control.Location.Y + _control.Height + 1), bitNew.Size));
142                             }
143                         }
144                     }
145                 }
146             }
147             blnLoading = false;
148         }
149 
150         /// 

151         /// Gets the color of the parent.
152         /// 
153         /// The c.
154         /// Color.
155         private Color GetParentColor(Control c)
156         {
157             if (c.Parent.BackColor != Color.Transparent)
158             {
159                 return c.Parent.BackColor;
160             }
161             return GetParentColor(c.Parent);
162         }

最后的话

如果你喜欢的话，请到 https://gitee.com/kwwwvagaa/net_winform_custom_control 点个星星吧