將不穩定的默認參數傳遞給C＃方法

Question

我想傳遞一個對象作為defUserInfo方法的默認值，但它不可能，因為它不是compile-time constant 。 有沒有其他方法可以使這項工作？

private static CustomerIdentifications defUserInfo = new CustomerIdentifications
{
    CustomerID = "1010",
    UniqueIdentifier = "1234"
};
public static HttpResponseMessage GenerateToken<T>(T userInfo = defUserInfo)
{
   // stuff
    return response;
}

Answer 1

您可以使用重載方法：

public static HttpResponseMessage GenerateToken()
{
    return GenerateToken(defUserInfo);
}
public static HttpResponseMessage GenerateToken<T>(T userInfo)
{
   // stuff
    return response;
}

Answer 2

如果CustomerIdentifications是一個結構，您可以通過使用struct屬性而不是字段來模擬默認值：

using System;

struct CustomerIdentifications
{
    private string _customerID;
    private string _uniqueIdentifier;

    public CustomerIdentifications(string customerId, string uniqueId)
    {
      _customerID = customerId;
      _uniqueIdentifier = uniqueId;
    }

    public string CustomerID { get { return _customerID ?? "1010"; } }
    public string UniqueIdentifier { get { return _uniqueIdentifier ?? "1234"; } }
}

class App
{
  public static void Main()
  {
    var id = GenerateToken<CustomerIdentifications>();
    Console.WriteLine(id.CustomerID);
    Console.WriteLine(id.UniqueIdentifier);
  }

  public static T GenerateToken<T>(T userInfo = default(T))
  {
    // stuff
    return userInfo;
  }
}