动态调用对象事件
2010-09-30 22:39:56 来源:WEB开发网对某个控件的事件进行编程;如,需要将当前运行期的按钮替换掉,并且保留它的原始事件引用;方法如下:
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测试代码
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private void button1_Click(object sender, EventArgs e)
{
MessageBox.Show("click by " + ((Button)sender).Name);
}
public void button2_Click(object sender, EventArgs e)
{
//调用button1 的click事件,并传递参数
CalleventRaiseEvent(button1, "Click", button1, null);
}
private void button3_Click(object sender, EventArgs e)
{
//构造个新的按钮
var btn3 = new Button { Name = "btnTest_createNew", Text = "新按钮", Parent = this,
Left = button1.Left + button1.Width + 10, Top = button1.Top, Visible = true };
//btn3.Click += (s, a) => CalleventRaiseEvent(button1, "Click", button1, null);
//将旧按钮事件放到新按钮上去
ReplaceEvent(button1, btn3, "Click");
//删除旧按钮
button1.Dispose();
button1 = null;
}
/// <summary>
/// 替换事件到控件
/// 必须保证 EventHandler 类型一致,否则会失败
/// </summary>
/// <param name="sourceControl">原控件</param>
/// <param name="destControl">目标控件</param>
/// <param name="eventName">事件明</param>
public void ReplaceEvent(Control sourceControl, Control destControl, string eventName)
{
if (sourceControl == null || destControl == null || string.IsNullOrEmpty(eventName))
throw new NullReferenceException();
Type type = sourceControl.GetType();
PropertyInfo propertyInfo = type.GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);
var eventHandlerList = (EventHandlerList)propertyInfo.GetValue(sourceControl, null);
FieldInfo fieldInfo = (typeof(Control)).GetField("Event" + eventName, BindingFlags.Static | BindingFlags.NonPublic);
Delegate d = eventHandlerList[fieldInfo.GetValue(null)];
if (d != null)
{
foreach (Delegate di in d.GetInvocationList())
destControl.GetType().GetEvent(eventName).AddEventHandler(destControl, d);
}
else
throw new InvalidCastException("无效的事件转换!");
}
/// <summary>
/// 调用事件方法
/// </summary>
/// <param name="control">目标控件</param>
/// <param name="eventName">方法名</param>
/// <param name="args">方法参数</param>
public void CalleventRaiseEvent(Control control, string eventName, params object[] args)
{
if (control == null || string.IsNullOrEmpty(eventName))
throw new NullReferenceException();
Type type = control.GetType();
EventInfo eventInfo = type.GetEvent(eventName);
MethodInfo methodInfo = eventInfo.GetRaiseMethod();
if (methodInfo != null)
methodInfo.Invoke(this, args);
else
{
PropertyInfo propertyInfo = type.GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);
var eventHandlerList = (EventHandlerList)propertyInfo.GetValue(control, null);
FieldInfo fieldInfo = (typeof(Control)).GetField("Event" + eventName, BindingFlags.Static | BindingFlags.NonPublic);
Delegate d = eventHandlerList[fieldInfo.GetValue(null)];
if (d != null)
{
foreach (Delegate di in d.GetInvocationList())
di.DynamicInvoke(args);
}
else
throw new NullReferenceException("无效的事件激发!");
}
}
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