Default parameter specifiers are not permitted

Question

I have the following code that gives the error

Default parameter specifiers are not permitted

How can this be fixed?

bool listSubscribe(string apikey, string id, string email_address, string [] merge_vars, string email_type="html", bool double_optin=false, bool replace_interests=true, bool send_welcome=false); bool listUnsubscribe(string apikey, string id, string email_address, bool delete_menber=false, bool send_goodbye=true, bool send_notify=true);

which version of Visual Studio and which .NET framework are you using? are these methods inside a Web form or what kind of class? — Davide Piras
– Davide Piras, Commented Oct 19, 2011 at 14:00
This might be worth reading: blogs.msdn.com/b/ericlippert/archive/2011/05/12/… — Johann Blais
– Johann Blais, Commented Oct 19, 2011 at 14:09
you need set language version in project properties, see stackoverflow.com/a/8325095/451495 — gdbdable
– gdbdable, Commented Apr 23, 2012 at 8:38

LarsTech · Accepted Answer · 2011-10-19 15:37:29Z

20

As per your error message, you can't do that in v3.5.

The work around is multiple constructors:

bool listUnsubscribe(string apikey, string id, string email_address) { return listUnsubscribe(apikey, id, email_address, false, true, true); } bool listUnsubscribe(string apikey, string id, string email_address, bool delete_menber, bool send_goodbye, bool send_notify) { return whatever; }

answered Oct 19, 2011 at 15:37

LarsTech

81.9k14 gold badges161 silver badges237 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Mohammad Azeem Ahmad Over a year ago

Hi LarsTech I am doing this work in the interface so therefore it didn't allow to define the definition of the function, Could you recomeend any other solution for it.

LarsTech Over a year ago

@user1003290 No, you won't get that to work in an interface. The interface would have to have all of the multiple constructors, and then in the class that consumes the interface, you would have to set the defaults. It can't be done from the interface alone.

wjfamilia · Accepted Answer · 2012-01-28 04:13:49Z

I just now encountered this error and my project is also targeting 4.0 and not 3.5 or below.

I toggled it to 3.5 and then back to 4.0 and then the error went away. Hopefully these steps will work for you, or someone else.

To add to this, after several years, the toggling added a targetFramework="4.0" to the <compilation> node of the Web.config which could be manually added to resolve this as well.

p.campbell · Accepted Answer · 2011-10-19 14:10:30Z

7

The application/class library is not set to target .NET 4 Framework. Adjust in the project's settings page.

enter image description here

answered Oct 19, 2011 at 14:10

p.campbell

101k70 gold badges264 silver badges326 bronze badges

1 Comment

Mohammad Azeem Ahmad Over a year ago

OK p.campbell but whether there is not any alternative of it in .net framework 3.5

Peter Mortensen · Accepted Answer · 2017-01-15 10:48:18Z

5

Optional parameters are a feature of C# 4, not present in earlier versions. Since you're using .NET 3.5, you can't use optional parameters.

Either switch to .NET 4.0, or use overloaded methods instead.

edited Jan 15, 2017 at 10:48

Peter Mortensen

31.4k22 gold badges110 silver badges134 bronze badges

answered Oct 19, 2011 at 15:43

Rik

29.3k14 gold badges52 silver badges69 bronze badges

1 Comment

gdbdable Over a year ago

-1, optional parameters can be used with .net 3.5, it need to set language version to default see stackoverflow.com/a/8325095/451495

Collectives™ on Stack Overflow

Default parameter specifiers are not permitted

4 Answers 4

2 Comments

1 Comment

1 Comment

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

1 Comment

1 Comment

1 Comment

Linked

Related