官网
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 /// <summary> 2 /// The m control cache 3 /// </summary> 4 Dictionary<Control, bool> m_controlCache = new Dictionary<Control, bool>(); 5 6 #region 构造函数 English:Constructor 7 /// <summary> 8 /// Initializes a new instance of the <see cref="ShadowComponent" /> class. 9 /// </summary> 10 public ShadowComponent() 11 { 12 13 } 14 15 /// <summary> 16 /// Initializes a new instance of the <see cref="ShadowComponent" /> class. 17 /// </summary> 18 /// <param name="container">The container.</param> 19 public ShadowComponent(IContainer container) 20 : this() 21 { 22 container.Add(this); 23 } 24 #endregion 25 26 /// <summary> 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 /// </summary> 29 /// <param name="extendee">要接收扩展程序属性的 <see cref="T:System.Object" />。</param> 30 /// <returns>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。</returns> 31 public bool CanExtend(object extendee) 32 { 33 if (extendee is Control && !(extendee is Form)) 34 return true; 35 return false; 36 } 37 38 /// <summary> 39 /// Gets the show shadow. 40 /// </summary> 41 /// <param name="control">The control.</param> 42 /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns> 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 /// <summary> 53 /// Sets the show shadow. 54 /// </summary> 55 /// <param name="control">The control.</param> 56 /// <param name="isShowShadow">if set to <c>true</c> [is show shadow].</param> 57 public void SetShowShadow(Control control, bool isShowShadow) 58 { 59 control.ParentChanged += control_ParentChanged; 60 m_controlCache[control] = isShowShadow; 61 } 62 63 /// <summary> 64 /// Handles the ParentChanged event of the control control. 65 /// </summary> 66 /// <param name="sender">The source of the event.</param> 67 /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param> 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 /// <summary> 85 /// The LST paint event control 86 /// </summary> 87 List<Control> lstPaintEventControl = new List<Control>(); 88 /// <summary> 89 /// The shadow height 90 /// </summary> 91 private float shadowHeight = 0.3f; 92 93 /// <summary> 94 /// Gets or sets the height of the shadow. 95 /// </summary> 96 /// <value>The height of the shadow.</value> 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 /// <summary> 104 /// The BLN loading 105 /// </summary> 106 bool blnLoading = false; 107 /// <summary> 108 /// Handles the Paint event of the Parent control. 109 /// </summary> 110 /// <param name="sender">The source of the event.</param> 111 /// <param name="e">The <see cref="PaintEventArgs"/> instance containing the event data.</param> 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 /// <summary> 151 /// Gets the color of the parent. 152 /// </summary> 153 /// <param name="c">The c.</param> 154 /// <returns>Color.</returns> 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