使用泛型类型来调用重载函数

Question

StreamWrite.Write is overloaded for Int16 , Int32 , Int64 , Double , Single , String and many more.

Why do I need to use dynamic? When calling the WriteList Method, the compiler knows that it is called for Int32 , String , ... .
So why can't I use e (of type T=Int32 ) directly in StreamWrite.Write ?

public void WriteList<T>(List<T> list) 
{
  int count = list.Count();
  StreamWriter.Write(count);
  foreach(T e in list) 
  {
    dynamic d = e;
    StreamWriter.Write(d);
  }
}

Answer 1

Because overload resolution (in the absence of dynamic ) happens at compile time, and at compile time, the actual type of T is unknown, since generics are a runtime feature.

The compiler doesn't know which method token of Write to include in the IL when compiling WriteList .