官網
http://www.hzhcontrols.com
前提
入行已經7,8年了，一直想做一套漂亮點的自定義控制元件，于是就有了本系列文章，
GitHub：https://github.com/kwwwvagaa/NetWinformControl
碼云：https://gitee.com/kwwwvagaa/net_winform_custom_control.git
如果覺得寫的還行，請點個 star 支持一下吧
歡迎前來交流探討： 企鵝群568015492 
麻煩博客下方點個【推薦】，謝謝
NuGet
Install-Package HZH_Controls
目錄
https://www.cnblogs.com/bfyx/p/11364884.html
用處及效果
此效果只是牛刀小試，需要注意的是，像textbox這樣的控制元件并不起作用，請注意，
你可以向目標控制元件繪圖，畫任何你想畫的東西，此效果只是向控制元件覆寫一個半透明隨機顏色
準備作業
沒什么可準備的
開始
添加一個類GraphicalOverlay ，繼承Component
代碼比較少，一次全上了，主要就是用控制元件的paint事件搞事情，邏輯比較簡單
1 using System; 2 using System.ComponentModel; 3 using System.Drawing; 4 using System.Windows.Forms; 5 6 namespace HZH_Controls.Controls 7 { 8 [DefaultEvent("Paint")] 9 public partial class GraphicalOverlay : Component 10 { 11 public event EventHandler<PaintEventArgs> Paint; 12 13 public GraphicalOverlay() 14 { 15 InitializeComponent(); 16 } 17 18 public GraphicalOverlay(IContainer container) 19 { 20 container.Add(this); 21 22 InitializeComponent(); 23 } 24 private Control owner; 25 public Control Owner 26 { 27 get { return owner; } 28 set 29 { 30 // The owner form cannot be set to null. 31 if (value =https://www.cnblogs.com/bfyx/p/= null) 32 throw new ArgumentNullException(); 33 34 // The owner form can only be set once. 35 if (owner != null) 36 throw new InvalidOperationException(); 37 38 // Save the form for future reference. 39 owner = value; 40 41 // Handle the form's Resize event. 42 owner.Resize += new EventHandler(Form_Resize); 43 44 // Handle the Paint event for each of the controls in the form's hierarchy. 45 ConnectPaintEventHandlers(owner); 46 } 47 } 48 49 private void Form_Resize(object sender, EventArgs e) 50 { 51 owner.Invalidate(true); 52 } 53 54 private void ConnectPaintEventHandlers(Control control) 55 { 56 // Connect the paint event handler for this control. 57 // Remove the existing handler first (if one exists) and replace it. 58 control.Paint -= new PaintEventHandler(Control_Paint); 59 control.Paint += new PaintEventHandler(Control_Paint); 60 61 control.ControlAdded -= new ControlEventHandler(Control_ControlAdded); 62 control.ControlAdded += new ControlEventHandler(Control_ControlAdded); 63 64 // Recurse the hierarchy. 65 foreach (Control child in control.Controls) 66 ConnectPaintEventHandlers(child); 67 } 68 69 private void Control_ControlAdded(object sender, ControlEventArgs e) 70 { 71 // Connect the paint event handler for the new control. 72 ConnectPaintEventHandlers(e.Control); 73 } 74 75 private void Control_Paint(object sender, PaintEventArgs e) 76 { 77 // As each control on the form is repainted, this handler is called. 78 79 Control control = sender as Control; 80 Point location; 81 82 // Determine the location of the control's client area relative to the form's client area. 83 if (control == owner) 84 // The form's client area is already form-relative. 85 location = control.Location; 86 else 87 { 88 // The control may be in a hierarchy, so convert to screen coordinates and then back to form coordinates. 89 location = owner.PointToClient(control.Parent.PointToScreen(control.Location)); 90 91 // If the control has a border shift the location of the control's client area. 92 location += new Size((control.Width - control.ClientSize.Width) / 2, (control.Height - control.ClientSize.Height) / 2); 93 } 94 95 // Translate the location so that we can use form-relative coordinates to draw on the control. 96 if (control != owner) 97 e.Graphics.TranslateTransform(-location.X, -location.Y); 98 99 // Fire a paint event.100 OnPaint(sender, e);101 }102 103 private void OnPaint(object sender, PaintEventArgs e)104 {105 // Fire a paint event.106 // The paint event will be handled in Form1.graphicalOverlay1_Paint().107 108 if (Paint != null)109 Paint(sender, e);110 }111 }112 }113 114 namespace System.Windows.Forms115 {116 using System.Drawing;117 118 public static class Extensions119 {120 public static Rectangle Coordinates(this Control control)121 {122 // Extend System.Windows.Forms.Control to have a Coordinates property.123 // The Coordinates property contains the control's form-relative location.124 Rectangle coordinates;125 Form form = (Form)control.TopLevelControl;126 127 if (control == form)128 coordinates = form.ClientRectangle;129 else130 coordinates = form.RectangleToClient(control.Parent.RectangleToScreen(control.Bounds));131 132 return coordinates;133 }134 }135 }
最后的話
如果你喜歡的話，請到 https://gitee.com/kwwwvagaa/net_winform_custom_control 點個星星吧
轉載請註明出處，本文鏈接：https://www.uj5u.com/net/4897.html
標籤：WinForm