如何判断控件的事件是否存在

使用示例

var isBind = IsBindEvent(comboBox.GetType(), comboBox, "comboBox_TextChanged");

if (!isBind)

{

comboBox.TextChanged += comboBox_TextChanged;

}

//是否已经绑定了事件private bool IsBindEvent(Type type, Control con, string eventName){    bool isBind = false;    PropertyInfo pi = type.GetProperty("Events", BindingFlags.Instance | BindingFlags.NonPublic);   //获取type类定义的所有事件的信息    EventHandlerList ehl = (EventHandlerList)pi.GetValue(con, null);    //获取con对象的事件处理程序列表    FieldInfo fieldInfo = (typeof(Control)).GetField("EventText", BindingFlags.Static | BindingFlags.NonPublic); //获取Control类Click事件的字段信息    Delegate d = ehl[fieldInfo.GetValue(null)];    if (d == null)    {        return isBind;    }    foreach (Delegate del in d.GetInvocationList())    {         if (del.Method.Name == eventName)        {            isBind = true;            break;        }    }    return isBind;}