为什么没有对EventHandler <TEventArgs>的约束？

Question

我只是偶然发现(编译时我认为不会编译的东西)EventHandler 并不局限于System.EventArgs类型.

这是内联文档:

#region Assembly mscorlib.dll, v4.0.0.0
// C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\mscorlib.dll
#endregion

namespace System
{
    // Summary:
    //     Represents the method that will handle an event.
    //
    // Parameters:
    //   sender:
    //     The source of the event.
    //
    //   e:
    //     An System.EventArgs that contains the event data.
    //
    // Type parameters:
    //   TEventArgs:
    //     The type of the event data generated by the event.
    [Serializable]
    public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e);
}

这是文档和实现之间的不匹配吗？

我问,因为我很好奇.这根本不是抱怨.

Answer 1

在.net 4.5中删除了类型约束.

这是.net 4.5签名. http://msdn.microsoft.com/en-us/library/db0etb8x%28v=vs.110%29.aspx

[SerializableAttribute]
public delegate void EventHandler<TEventArgs>(
    Object sender,
    TEventArgs e
)

这是.net 4.0签名. http://msdn.microsoft.com/en-us/library/db0etb8x%28v=vs.100%29.aspx

[SerializableAttribute]
public delegate void EventHandler<TEventArgs>(
    Object sender,
    TEventArgs e
)
where TEventArgs : EventArgs