?????????C#??????????“???”????ò?????????????????????????????????????????????“???”?????????“?????????????????????д???”????????????????????壬????????“???”????????н???????????????????????????У???????е?????????????????
????“???”?????????????????е?????????????????????????“????”??????????С??????????????????κζ?????????á????????У???????з??????????????????п??????????????????????????е???????????????????????
??????“???”?????????У????????????????“???????“??????“???????”??????????????????????????????????”??????“?е?”????-??????“??”????-???“???????????壨????飬?????????????????????????????????????????????????”??????????????????????????“??????μ?????????????????????????μ??????е??????????????е????
??????C#???????delegate???????壬???new????????????????????????????????????????????????????????????ж??????????????淽??????????C#?У???????????????????????????е???????????????????????????????????????????????????????????????????????д????????????????????????ж??壬???????????Χ????塣???????????????????????????????????????С?
?????????????????????”???“????????????????????
????1.????????????
????2.??????????????????????е????
????3.?????????????????
????4.???????????????
?????????????μ??????????????????4????????
???????????????????????????????б??????????????漲???????????????????????????????????????????????????????????????????????????÷????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????е?????????????????е?????????????????????????
?????????????”???“??????????????????????????????ν?????????”???“????????е??????????
??????????????????????????У????????????????????б????????????System.Delegate?????????????????????Combine()??Remove()?????????????????????????????????????????????У????????-=??+=????????
??????FCL?У????е???????????????MulticastDelegate??????????System.MulticastDelegate?????С?
???????????????Combine()??????????????
[System.Runtime.InteropServices.ComVisible(true)]
public static Delegate Combine(params Delegate[] delegates)
{
if (delegates == null || delegates.Length == 0)
return null;
Delegate d = delegates[0];
for (int i = 1; i < delegates.Length; i++)
d = Combine(d??delegates[i]);
return d;
}
public static Delegate Combine(Delegate a?? Delegate b)
{
if ((Object)a == null)
return b;
return  a.CombineImpl(b);
}
?????????????????System.Delegate?????У?CombineImpl??????MulticastDelegate??д??
[System.Security.SecuritySafeCritical]
protected override sealed Delegate CombineImpl(Delegate follow)
{
if ((Object)follow == null)
return this;
if (!InternalEqualTypes(this?? follow))
throw new ArgumentException(Environment.GetResourceString("Arg_DlgtTypeMis"));
MulticastDelegate dFollow = (MulticastDelegate)follow;
Object[] resultList;
int followCount = 1;
Object[] followList = dFollow._invocationList as Object[];
if (followList != null)
followCount = (int)dFollow._invocationCount;
int resultCount;
Object[] invocationList = _invocationList as Object[];
if (invocationList == null)
{
resultCount = 1 + followCount;
resultList = new Object[resultCount];
resultList[0] = this;
if (followList == null)
{
resultList[1] = dFollow;
}
else
{
for (int i = 0; i < followCount; i++)
resultList[1 + i] = followList[i];
}
return NewMulticastDelegate(resultList?? resultCount);
}
else
{
int invocationCount = (int)_invocationCount;
resultCount = invocationCount + followCount;
resultList = null;
if (resultCount <= invocationList.Length)
{
resultList = invocationList;
if (followList == null)
{
if (!TrySetSlot(resultList?? invocationCount?? dFollow))
resultList = null;
}
else
{
for (int i = 0; i < followCount; i++)
{
if (!TrySetSlot(resultList?? invocationCount + i?? followList[i]))
{
resultList = null;
break;
}
}
}
}
if (resultList == null)
{
int allocCount = invocationList.Length;
while (allocCount < resultCount)
allocCount *= 2;
resultList = new Object[allocCount];
for (int i = 0; i < invocationCount; i++)
resultList[i] = invocationList[i];
if (followList == null)
{
resultList[invocationCount] = dFollow;
}
else
{
for (int i = 0; i < followCount; i++)
resultList[invocationCount + i] = followList[i];
}
}
return NewMulticastDelegate(resultList?? resultCount?? true);
}
}