Overloading a method with different return types but the same parameter lists

[Ryan Taylor]

Hello.

I am trying to overload a method so that I have four possible working
copies. The only difference between the four methods is what to search by
and in what manner to return the results. So I have the following.

public static ArrayList GetRoles(int userID)
public static ArrayList GetRoles(string username)
public static string GetRoles(int userID) // Error 1
public static string GetRoles(string username) // Error 2

But I am receiving the following errors.

Error 1.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(117):
Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

Error 2.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(120):
Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

How can I overload these methods to provide the functionality that I want.
Thanks in advance.

Ryan Taylor

[Jochen Kalmbach]

Hello Ryan,

How can I overload these methods to provide the functionality that I
want. Thanks in advance.

You can´t.
Maybe it is supported in C# 2 !?

--
Greetings
Jochen

[Jon Skeet [C# MVP]]

Jochen Kalmbach <no********************@holzma.de> wrote:

How can I overload these methods to provide the functionality that I
want. Thanks in advance.

You can´t.
Maybe it is supported in C# 2 !?

No, it's not, thank goodness. I for one don't want which method is
called to be determined by what I do with the returned value.

--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too

[Dennis Myrén]

Sorry that is impossible.
An advice would be to rename the methods GetRoleList or something.

This is a limitation of C#, as it is supported in the Intermediate Language.

--
Regards,
Dennis JD Myrén
Oslo Kodebureau
"Ryan Taylor" <rt*****@stgeorgeconsulting.com> wrote in message
news:Oj**************@TK2MSFTNGP12.phx.gbl...

Hello.

I am trying to overload a method so that I have four possible working
copies. The only difference between the four methods is what to search by
and in what manner to return the results. So I have the following.

public static ArrayList GetRoles(int userID)
public static ArrayList GetRoles(string username)
public static string GetRoles(int userID) // Error 1
public static string GetRoles(string username) // Error 2

But I am receiving the following errors.

Error 1.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(117): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

Error 2.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(120): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

How can I overload these methods to provide the functionality that I want.
Thanks in advance.

Ryan Taylor

[Ryan Taylor]

Thanks. I won't be chasing my tail any longer. I hope it is supported in
2.0.

Ryan Taylor

[William Stacey [MVP]]

Can't do, not in 2.0 either IIRC. Return your own collection class (i.e.
inherits ICollection). Your ToString() method (or other) on the collection
class would return the string so you could:

MyRoles roles = GetRoles(2);
Console.WriteLine(roles.count);
Console.WriteLine(roles.ToString());
roles = GetRoles("joe");

Then you only need two overloads.

public class MyRoles : ICollection
{
private ArrayList roles = new ArrayList()
....
public override string ToString()
{
StringBuilder sb = new StringBuilder();
foreach(object in roles)
{
// Do something to format.
}
return sb.ToString();
}
}
--
William Stacey, MVP

"Ryan Taylor" <rt*****@stgeorgeconsulting.com> wrote in message
news:Oj**************@TK2MSFTNGP12.phx.gbl...

Hello.

I am trying to overload a method so that I have four possible working
copies. The only difference between the four methods is what to search by
and in what manner to return the results. So I have the following.

public static ArrayList GetRoles(int userID)
public static ArrayList GetRoles(string username)
public static string GetRoles(int userID) // Error 1
public static string GetRoles(string username) // Error 2

But I am receiving the following errors.

Error 1.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(117): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

Error 2.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(120): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

How can I overload these methods to provide the functionality that I want.
Thanks in advance.

Ryan Taylor

[C.Aroonyinmongkol]

It is not possible and it should not be possible in C# 2!
How can compiler know which version you would like to use if you call

GetRoles(id);

and ignore the return type. This is the reason why function overloading does
not include the return type.

However you can implement these method as below.

void GetRoles(int id, out ArrayList al);
void GetRoles(string username, out ArrayList al);
void GetRoles(int id, out string s);
void GetRoles(string username, out string s);

Anyway, these are a bit ugly, in my opinion !!!

Best regards
/C.Aroonyingmongkol

"Ryan Taylor" <rt*****@stgeorgeconsulting.com> wrote in message
news:Oj**************@TK2MSFTNGP12.phx.gbl...

Hello.

I am trying to overload a method so that I have four possible working
copies. The only difference between the four methods is what to search by
and in what manner to return the results. So I have the following.

public static ArrayList GetRoles(int userID)
public static ArrayList GetRoles(string username)
public static string GetRoles(int userID) // Error 1
public static string GetRoles(string username) // Error 2

But I am receiving the following errors.

Error 1.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(117): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

Error 2.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(120): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

How can I overload these methods to provide the functionality that I want.
Thanks in advance.

Ryan Taylor

[Robert Jordan]

C.Aroonyinmongkol wrote:

It is not possible and it should not be possible in C# 2!
How can compiler know which version you would like to use if you call

GetRoles(id);

and ignore the return type. This is the reason why function overloading does
not include the return type.

The other reason is that passing a by-result overloaded
method as an argument to another method, which in turn
has overloaded parameters, is ambigous:

class A {
string Get();
int Get();
}

class B {
void Process(string s);
void Process(int i);
}

b.Process(a.Get());

which Get() should be called? you'll end up having to cast:

b.Process((int)Get());

and the benefit of by-result overloading is gone.

Bye
Rob

[Lateralus [MCAD.Net]]

Ryan,
If you can handle not having the methods be static, one way I get around
this is to implement different interfaces:

public interface IRolesArrayList
{
ArrayList GetRoles(int userID)
ArrayList GetRoles(string username)
}

public interface IRolesString
{
string GetRoles(int userID)
string GetRoles(string username)
}

public class MyClass : IRolesArrayList, IRolesString
{
ArrayList IRolesArrayList.GetRoles(int userID)
{
//implement code
}

ArrayList IRolesArrayList.GetRoles(string userName)
{
//implement code
}

string IRolesArrayList.GetRoles(int userID)
{
//implement code
}

string IRolesArrayList.GetRoles(string userName)
{
//implement code
}
}

--
Lateralus [MCAD.Net]
"Ryan Taylor" <rt*****@stgeorgeconsulting.com> wrote in message
news:Oj**************@TK2MSFTNGP12.phx.gbl...

Hello.

I am trying to overload a method so that I have four possible working
copies. The only difference between the four methods is what to search by
and in what manner to return the results. So I have the following.

public static ArrayList GetRoles(int userID)
public static ArrayList GetRoles(string username)
public static string GetRoles(int userID) // Error 1
public static string GetRoles(string username) // Error 2

But I am receiving the following errors.

Error 1.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(117): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

Error 2.
C:\Projects\acmsproject\trunk\acms\source\DataAcce ss\DatabaseAccess.cs(120): Class 'acms.DataAccess.DatabaseAccess' already defines a member called
'GetRoles' with the same parameter types

How can I overload these methods to provide the functionality that I want.
Thanks in advance.

Ryan Taylor

[Ryan Taylor]

Wow. Thanks everyone for the great support. I have a pretty simple need, so
I went for a simple solution. I named my function that return an ArrayList
as GetRolesList(...) and the function that returns a string I named
GetRoles(...). GetRoles(...) then calls GetRolesList(...) and loops through
the resulting array to build my string and return that to the user.

There are definately some interesting things that can be done in C#. I am a
newbie at the whole .NET philosophy, but so far the Microsoft juice isn't as
sour as it once was.

Thanks again for the wide support.

Ryan Taylor