要在控件上创建新的事件处理程序,可以这样做
c.Click += new EventHandler(mainFormButton_Click);
或者这个
c.Click += mainFormButton_Click;
要删除事件处理程序,可以这样做
c.Click -= mainFormButton_Click;
但是如何从事件中删除所有事件处理程序呢?
要在控件上创建新的事件处理程序,可以这样做
c.Click += new EventHandler(mainFormButton_Click);
或者这个
c.Click += mainFormButton_Click;
要删除事件处理程序,可以这样做
c.Click -= mainFormButton_Click;
但是如何从事件中删除所有事件处理程序呢?
当前回答
我刚刚发现如何在设置WinForms控件的属性时挂起事件。它将删除控件中的所有事件:
namespace CMessWin05
{
public class EventSuppressor
{
Control _source;
EventHandlerList _sourceEventHandlerList;
FieldInfo _headFI;
Dictionary<object, Delegate[]> _handlers;
PropertyInfo _sourceEventsInfo;
Type _eventHandlerListType;
Type _sourceType;
public EventSuppressor(Control control)
{
if (control == null)
throw new ArgumentNullException("control", "An instance of a control must be provided.");
_source = control;
_sourceType = _source.GetType();
_sourceEventsInfo = _sourceType.GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);
_sourceEventHandlerList = (EventHandlerList)_sourceEventsInfo.GetValue(_source, null);
_eventHandlerListType = _sourceEventHandlerList.GetType();
_headFI = _eventHandlerListType.GetField("head", BindingFlags.Instance | BindingFlags.NonPublic);
}
private void BuildList()
{
_handlers = new Dictionary<object, Delegate[]>();
object head = _headFI.GetValue(_sourceEventHandlerList);
if (head != null)
{
Type listEntryType = head.GetType();
FieldInfo delegateFI = listEntryType.GetField("handler", BindingFlags.Instance | BindingFlags.NonPublic);
FieldInfo keyFI = listEntryType.GetField("key", BindingFlags.Instance | BindingFlags.NonPublic);
FieldInfo nextFI = listEntryType.GetField("next", BindingFlags.Instance | BindingFlags.NonPublic);
BuildListWalk(head, delegateFI, keyFI, nextFI);
}
}
private void BuildListWalk(object entry, FieldInfo delegateFI, FieldInfo keyFI, FieldInfo nextFI)
{
if (entry != null)
{
Delegate dele = (Delegate)delegateFI.GetValue(entry);
object key = keyFI.GetValue(entry);
object next = nextFI.GetValue(entry);
Delegate[] listeners = dele.GetInvocationList();
if(listeners != null && listeners.Length > 0)
_handlers.Add(key, listeners);
if (next != null)
{
BuildListWalk(next, delegateFI, keyFI, nextFI);
}
}
}
public void Resume()
{
if (_handlers == null)
throw new ApplicationException("Events have not been suppressed.");
foreach (KeyValuePair<object, Delegate[]> pair in _handlers)
{
for (int x = 0; x < pair.Value.Length; x++)
_sourceEventHandlerList.AddHandler(pair.Key, pair.Value[x]);
}
_handlers = null;
}
public void Suppress()
{
if (_handlers != null)
throw new ApplicationException("Events are already being suppressed.");
BuildList();
foreach (KeyValuePair<object, Delegate[]> pair in _handlers)
{
for (int x = pair.Value.Length - 1; x >= 0; x--)
_sourceEventHandlerList.RemoveHandler(pair.Key, pair.Value[x]);
}
}
}
}
其他回答
如果你真的要这么做……这需要深思熟虑和相当长的时间。事件处理程序在控件内的事件委托映射中进行管理。你需要
在控件实例中反射并获取此映射。 迭代每个事件,获取委托 每个委托可以依次是一系列链接的事件处理程序。调用obControl。RemoveHandler(事件处理程序)
简而言之,工作量很大。在理论上是可能的。我从没试过这样的东西。
看看是否可以对订阅-退订阶段有更好的控制/纪律。
你们对自己太苛刻了。很简单:
void OnFormClosing(object sender, FormClosingEventArgs e)
{
foreach(Delegate d in FindClicked.GetInvocationList())
{
FindClicked -= (FindClickedHandler)d;
}
}
我找到了这个答案,它几乎满足了我的需求。感谢SwDevMan81的课程。我已经修改了它,以允许抑制和恢复单个方法,我想我应该把它贴在这里。
// This class allows you to selectively suppress event handlers for controls. You instantiate
// the suppressor object with the control, and after that you can use it to suppress all events
// or a single event. If you try to suppress an event which has already been suppressed
// it will be ignored. Same with resuming; you can resume all events which were suppressed,
// or a single one. If you try to resume an un-suppressed event handler, it will be ignored.
//cEventSuppressor _supButton1 = null;
//private cEventSuppressor SupButton1 {
// get {
// if (_supButton1 == null) {
// _supButton1 = new cEventSuppressor(this.button1);
// }
// return _supButton1;
// }
//}
//private void button1_Click(object sender, EventArgs e) {
// MessageBox.Show("Clicked!");
//}
//private void button2_Click(object sender, EventArgs e) {
// SupButton1.Suppress("button1_Click");
//}
//private void button3_Click(object sender, EventArgs e) {
// SupButton1.Resume("button1_Click");
//}
using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Windows.Forms;
using System.ComponentModel;
namespace Crystal.Utilities {
public class cEventSuppressor {
Control _source;
EventHandlerList _sourceEventHandlerList;
FieldInfo _headFI;
Dictionary<object, Delegate[]> suppressedHandlers = new Dictionary<object, Delegate[]>();
PropertyInfo _sourceEventsInfo;
Type _eventHandlerListType;
Type _sourceType;
public cEventSuppressor(Control control) {
if (control == null)
throw new ArgumentNullException("control", "An instance of a control must be provided.");
_source = control;
_sourceType = _source.GetType();
_sourceEventsInfo = _sourceType.GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);
_sourceEventHandlerList = (EventHandlerList)_sourceEventsInfo.GetValue(_source, null);
_eventHandlerListType = _sourceEventHandlerList.GetType();
_headFI = _eventHandlerListType.GetField("head", BindingFlags.Instance | BindingFlags.NonPublic);
}
private Dictionary<object, Delegate[]> BuildList() {
Dictionary<object, Delegate[]> retval = new Dictionary<object, Delegate[]>();
object head = _headFI.GetValue(_sourceEventHandlerList);
if (head != null) {
Type listEntryType = head.GetType();
FieldInfo delegateFI = listEntryType.GetField("handler", BindingFlags.Instance | BindingFlags.NonPublic);
FieldInfo keyFI = listEntryType.GetField("key", BindingFlags.Instance | BindingFlags.NonPublic);
FieldInfo nextFI = listEntryType.GetField("next", BindingFlags.Instance | BindingFlags.NonPublic);
retval = BuildListWalk(retval, head, delegateFI, keyFI, nextFI);
}
return retval;
}
private Dictionary<object, Delegate[]> BuildListWalk(Dictionary<object, Delegate[]> dict,
object entry, FieldInfo delegateFI, FieldInfo keyFI, FieldInfo nextFI) {
if (entry != null) {
Delegate dele = (Delegate)delegateFI.GetValue(entry);
object key = keyFI.GetValue(entry);
object next = nextFI.GetValue(entry);
if (dele != null) {
Delegate[] listeners = dele.GetInvocationList();
if (listeners != null && listeners.Length > 0) {
dict.Add(key, listeners);
}
}
if (next != null) {
dict = BuildListWalk(dict, next, delegateFI, keyFI, nextFI);
}
}
return dict;
}
public void Resume() {
}
public void Resume(string pMethodName) {
//if (_handlers == null)
// throw new ApplicationException("Events have not been suppressed.");
Dictionary<object, Delegate[]> toRemove = new Dictionary<object, Delegate[]>();
// goes through all handlers which have been suppressed. If we are resuming,
// all handlers, or if we find the matching handler, add it back to the
// control's event handlers
foreach (KeyValuePair<object, Delegate[]> pair in suppressedHandlers) {
for (int x = 0; x < pair.Value.Length; x++) {
string methodName = pair.Value[x].Method.Name;
if (pMethodName == null || methodName.Equals(pMethodName)) {
_sourceEventHandlerList.AddHandler(pair.Key, pair.Value[x]);
toRemove.Add(pair.Key, pair.Value);
}
}
}
// remove all un-suppressed handlers from the list of suppressed handlers
foreach (KeyValuePair<object, Delegate[]> pair in toRemove) {
for (int x = 0; x < pair.Value.Length; x++) {
suppressedHandlers.Remove(pair.Key);
}
}
//_handlers = null;
}
public void Suppress() {
Suppress(null);
}
public void Suppress(string pMethodName) {
//if (_handlers != null)
// throw new ApplicationException("Events are already being suppressed.");
Dictionary<object, Delegate[]> dict = BuildList();
foreach (KeyValuePair<object, Delegate[]> pair in dict) {
for (int x = pair.Value.Length - 1; x >= 0; x--) {
//MethodInfo mi = pair.Value[x].Method;
//string s1 = mi.Name; // name of the method
//object o = pair.Value[x].Target;
// can use this to invoke method pair.Value[x].DynamicInvoke
string methodName = pair.Value[x].Method.Name;
if (pMethodName == null || methodName.Equals(pMethodName)) {
_sourceEventHandlerList.RemoveHandler(pair.Key, pair.Value[x]);
suppressedHandlers.Add(pair.Key, pair.Value);
}
}
}
}
}
}
删除按钮的所有处理程序: save.RemoveEvents ();
public static class EventExtension
{
public static void RemoveEvents<T>(this T target) where T : Control
{
var propInfo = typeof(T).GetProperty("Events", BindingFlags.NonPublic | BindingFlags.Instance);
var list = (EventHandlerList)propInfo.GetValue(target, null);
list.Dispose();
}
}
这不是对OP的回答,但我想我把它贴在这里,以防它能帮助到其他人。
/// <summary>
/// Method to remove a (single) SocketAsyncEventArgs.Completed event handler. This is
/// partially based on information found here: http://stackoverflow.com/a/91853/253938
///
/// But note that this may not be a good idea, being very .Net implementation-dependent. Note
/// in particular use of "m_Completed" instead of "Completed".
/// </summary>
private static void RemoveCompletedEventHandler(SocketAsyncEventArgs eventArgs)
{
FieldInfo fieldInfo = typeof(SocketAsyncEventArgs).GetField("m_Completed",
BindingFlags.Instance | BindingFlags.NonPublic);
eventArgs.Completed -= (EventHandler<SocketAsyncEventArgs>)fieldInfo.GetValue(eventArgs);
}