我想通过编程的方式调用控件的事件处理程序。例如:
DateTimePicker dtpLastConsummated;
我希望触发dtpLastConsummated
的TextChanged事件处理程序,我该怎么做?
在其他语言中,我会调用类似于以下内容的东西:
dtpLastConsummated.TextChanged(this, new EventArgs());
但在.NET中,您可以拥有多个事件处理程序:
dtpLastConsummated.Click +=new EventHandler(dtpLastConsummated_TextChanged);
dtpLastConsummated.Click +=new EventHandler(dtpLastConsummated_AnotherHandler);
dtpLastConsummated.Click +=new EventHandler(dtpLastConsummated_MoreHandlers);
...
dtpLastConsummated.Click +=new EventHandler(dtpLastConsummated_Nminus1);
所以你需要一种方法来触发所有附加的事件处理程序。
答案
以下代码将触发该事件:
Toolkit.FireEvent(dtpLastConsummated, "TextChanged", new EventArgs());
这是静态工具包函数的代码:
/// <summary>
/// Programatically fire an event handler of an object
/// </summary>
/// <param name="targetObject"></param>
/// <param name="eventName"></param>
/// <param name="e"></param>
public static void FireEvent(Object targetObject, string eventName, EventArgs e)
{
/*
* By convention event handlers are internally called by a protected
* method called OnEventName
* e.g.
* public event TextChanged
* is triggered by
* protected void OnTextChanged
*
* If the object didn't create an OnXxxx protected method,
* then you're screwed. But your alternative was over override
* the method and call it - so you'd be screwed the other way too.
*/
//Event thrower method name //e.g. OnTextChanged
String methodName = "On" + eventName;
MethodInfo mi = targetObject.GetType().GetMethod(
methodName,
BindingFlags.Instance | BindingFlags.NonPublic);
if (mi == null)
throw new ArgumentException("Cannot find event thrower named "+methodName);
mi.Invoke(targetObject, new object[] { e });
}
注意:我并不会为.NET框架中的每一个控件和第三方控件创建子类,并说服企业级开发人员将每个窗体改为使用我的自定义控件。