标签：控件 log required blog direction point layout else use
这是一个自定义事件的例子。C#、WinForm、Visual Studio 2017。
在HoverTreeForm中画一块草地，上面有许多草（模拟）。
HewenqiTianyi类模拟天气，会引发“风”事件（HoverTreeWindEvent），风有东风或西风，或静止。
当吹东风，草往西边倒，吹西风则往东边到。静止则草不会东歪西倒。
草地上每一颗草都监听HoverTreeWindEvent事件，根据风向（WindDdirection）调整姿态。
HewenqiTianyi中有定时器，每隔一段时间触发调整风向的事件。
由于监听到的“风”事件不是WinForm中的线程，要改变WinForm中“草”的姿态，
使用了BeginInvoke方法和委托，在WinForm线程外访问控件。具体看HoverTreeGrass用户控件。
by 何问起
参考：http://hovertree.com/h/bjag/k0qps1iw.htm
http://hovertree.com/h/bjag/cm8k4ja1.htm
效果图：
HewenqiTianyi类代码：
using System; using System.Timers; namespace TianYiHeWenQi { class HewenqiTianyi { public static event ActionEventHandler HoverTreeWindEvent; WindEventArgs _arg = new WindEventArgs(); public HewenqiTianyi() { Timer h_timer = new Timer(); h_timer.Interval = 3000; h_timer.Elapsed += H_timer_Elapsed; h_timer.Start(); } Random _HoverClock=new Random (); private void H_timer_Elapsed(object sender, ElapsedEventArgs e) { _arg.WindType = (WindDdirection)(_HoverClock.Next(3)); OnAction(_arg); } protected void OnAction(WindEventArgs ev) { HoverTreeWindEvent?.Invoke(ev); //相当于以下代码 //if (HoverTreeWindEvent != null) //{ // HoverTreeWindEvent(ev); //} } } class WindEventArgs : EventArgs { public WindDdirection WindType { get; set; } } enum WindDdirection { East, West, Static } delegate void ActionEventHandler(WindEventArgs ev); }
自定义用户控件代码：
using System; using System.Windows.Forms; namespace TianYiHeWenQi { public partial class HoverTreeGrass : UserControl { delegate void MySetText(string text); public HoverTreeGrass() { InitializeComponent(); HewenqiTianyi.HoverTreeWindEvent += HewenqiTianyi_HoverTreeWindEvent; } private void UpdateLabel(WindDdirection wd) { if (label_grass.InvokeRequired) { // 当一个控件的InvokeRequired属性值为真时，说明有一个创建它以外的线程想访问它 Action<WindDdirection> actionDelegate = (x) => { switch (x) { case WindDdirection.East: label_grass.Location = new System.Drawing.Point(40 - 9, label_grass.Location.Y); label_grass.Text="\\"; break; case WindDdirection.West: label_grass.Location = new System.Drawing.Point(40+9, label_grass.Location.Y); label_grass.Text = "/"; break; case WindDdirection.Static: label_grass.Location = new System.Drawing.Point(40, label_grass.Location.Y); label_grass.Text = "|"; break; } }; // 或者 // Action<string> actionDelegate = delegate(string txt) { this.label_grass.Text = txt; }; this.label_grass.BeginInvoke(actionDelegate, wd); } else { switch (wd) { case WindDdirection.East: label_grass.Text = "\\"; break; case WindDdirection.West: label_grass.Text = "/"; break; case WindDdirection.Static: label_grass.Text = "|"; break; } } } private void HewenqiTianyi_HoverTreeWindEvent(WindEventArgs ev) { UpdateLabel(ev.WindType); } } }
HoverTreeForm窗体代码：
using System.Windows.Forms; namespace TianYiHeWenQi { public partial class HoverTreeForm : Form { public HoverTreeForm() { InitializeComponent(); for (int i = 0; i < tableLayoutPanel_hovertree.ColumnCount; i++) { for (int j = 0; j < tableLayoutPanel_hovertree.RowCount; j++) { tableLayoutPanel_hovertree.Controls.Add(new HoverTreeGrass(), i, j); } } HewenqiTianyi h_ty = new HewenqiTianyi(); } } }
标签：控件 log required blog direction point layout else use
原文地址：http://www.cnblogs.com/jihua/p/csharpevent.html
