Can we make overload methods with same name but having different datatypes within in a Class

Question

Class StudentFeeCollection
{
public static bool CheckAdmissionMonth(int AdmissionNo)
 {
 }
public static DataTable CheckAdmissionMonth(int AdmissionNo)
 {
 }
}

Is this possible or not, please tell me.

For future reference, the compiler in your IDE could have told you this. Try to do a little exploring on your own before looking for someone to tell you--it will aid your learning greatly! — Brian Warshaw, Feb 06 '14 at 12:29

score 1 · Answer 1 · answered Feb 06 '14 at 12:19

1

You can use out parameter:

 class StudentFeeCollection
{
public static void CheckAdmissionMonth(int AdmissionNo, out bool result)
{
    ........
}
public static void CheckAdmissionMonth(int AdmissionNo, out DataTable tbl)
{
    .......
}

answered Feb 06 '14 at 12:19

Mohammad Arshad Alam

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Its just implementing function overloading – Mohammad Arshad Alam Feb 06 '14 at 12:21
@AlexD, Its a solution as per the question. It has not been mentioned about interface in the question – Mohammad Arshad Alam Feb 06 '14 at 13:04

score 0 · Answer 2 · answered Feb 06 '14 at 12:17

No, that's not possible. You need to make sure that the signature of each overload is unique.

From the documentation:

Changing the return type of a method does not make the method unique as stated 
in the common language runtime specification. You cannot define overloads that 
vary only by return type.

Reference: http://msdn.microsoft.com/en-us/library/vstudio/ms229029(v=vs.100).aspx

score 0 · Answer 3 · answered Feb 06 '14 at 12:18

This is not possible. Imagine you're the compiler or the runtime--how would you know which return type the code was asking for? If you really need to support returning multiple datatypes from a method, using generics is your best bet. That said, looking at your specific example, I suggest not doing it here. Having one method that returns either a boolean or a DataTable seems like a pretty shoddy design.

score 0 · Answer 4 · edited May 23 '17 at 12:28

You can overload by argument types in c# but not by return type. As Arshad said you can use out/ref parameters since these are arguments and not return types.

Also you can't overload by generic constraints of arguments(say having 2 versions where one is a struct and another is a class). see https://msmvps.com/blogs/jon_skeet/archive/2010/10/28/overloading-and-generic-constraints.aspx

one reason to avoid return type overloading, from the c++ language description:

The reason is to keep resolution for an individual operator or function call context-independent.

note: in some programming language like haskell you can overload by return types see Function overloading by return type? for more info

Can we make overload methods with same name but having different datatypes within in a Class

4 Answers4