Is there optional parameters in c# & how to use dat

Question

Hi...All, Could u please tell me dat Is there optional parameters in c# & how to use dat ??

John Penn · Answer

If not, then you can create an overloaded method that takes different parameters: void Foo() { Foo(null, null); } void Foo(int param1) { Foo(param1, null); } void Foo(int param1, string param2) { // determine if param1 and/or param2 are null . . . }

Vulpes · Answer

If you're using C# 4.0, then optional parameters are available. See the article on this topic in the sidebar to the right of this thread.

Sam Hobbs · Answer

Who is K?

madhav tare · Answer

K....thanks for ur reply .. But I am looking for only optional parameter..& not for verloading

madhav tare · Answer

Thanks ..I just seen that

Sam Hobbs · Answer

There are many .Net methods that take arrays of objects or arrays of a specified type such as arrays of strings.

Vulpes · Answer

If you're writing a library, then John's approach is arguably better even if you're using C# 4.0. This is because: 1. Optional parameters are not CLS compliant - there may be other .NET languages that don't support them even though the main ones (VB.Net, C++/CLI) do. 2. Using optional parameters bakes the default value into the method's signature and so, if you change it later, clients need to be recompiled. This isn't the case with John's method because, of course, the default value doesn't appear in the method's signature. The second of these is thought to be the reason why optional parameters were omitted from C# until version 4.0 but this objection was then overcome by the need to make Office interop easier. Previously it had been a PITA with the need to use Type.Missing for each optional argument in an Office interop method which you were not supplying explicitly. A related topic to optional parameters is named parameters for which there's also an article in the sidebar.

Is there optional parameters in c# & how to use dat

Answers (7)