Events cannot be declared with a delegate type that has a return type.

我该如何更正此代码？

C#：

using System;
[assembly: CLSCompliant(true)]

namespace Link.API
{
  public delegate decimal DecimalStringDelegate(string s);
  public delegate long OrderDelegateStatus(Order o);
  public delegate void LongDelegate(long val);
}

using System;
using System.Collections.Generic;
using System.Text;

namespace Link.API
{
  public interface TLServer
  {
    event LongDelegate newOrderCancelRequest;
    event OrderDelegateStatus newSendOrderRequest;
    string ClientName(int clientnum);
    bool SymbolSubscribed(string sym);

    Basket AllClientBasket { get; }
  }
}

VB.NET：

Imports System.Text
Imports System.Collections.Generic
Imports System
<Assembly: CLSCompliant(True)>

Namespace Link.API
  Public Delegate Function DecimalStringDelegate(ByVal s As String) As Decimal
  Public Delegate Function OrderDelegateStatus(ByVal o As Order) As Long
  Public Delegate Sub LongDelegate(ByVal val As Long)
End Namespace

Namespace Link.API
  Public Interface Server
    Event newOrderCancelRequest As LongDelegate
    Event newSendOrderRequest As OrderDelegateStatus
    Function ClientName(ByVal clientnum As Integer) As String
    Function SymbolSubscribed(ByVal sym As String) As Boolean
    ReadOnly Property AllClientBasket() As Basket
  End Interface
End Namespace