Partial Methods in C# and parameters

Question

Ref and out can change the behavior of function parameters. Sometimes we want the actual value of a variable to be copied as the parameter. Other times we want a reference. These modifiers affect definite assignment analysis.

My question is: can partial methods in C# have ref, out, optional input parameters?

https://learn.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/partial-classes-and-methods#partial-methods — user6144226, Aug 03 '17 at 16:39
From the above linked docs: *Partial methods can have ref but not out parameters.* — marc_s, Aug 03 '17 at 16:40

Felipe · Answer 1 · 2017-08-03T16:48:18.450

1

By experimentation with the code in this example it seems like you can find that it is possible to use ref, params, and default argument values, but not out

partial class A
{
    partial void OnSomethingHappened(string s);
    partial void useRef(ref string s);
    partial void useOpt(string s1, string s2 = null);
    partial void useArgs(params string [] s);
}

// This part can be in a separate file.
partial class A
{
    // Comment out this method and the program
    // will still compile.
    partial void OnSomethingHappened(String s)
    {
        Console.WriteLine("Something happened: {0}", s);
    }
}

Also, as explained by the docs linked by @user6144226 and pointed out by @marc_s:

Partial methods can have ref but not out parameters.

edited Aug 03 '17 at 16:48

answered Aug 03 '17 at 16:43

Felipe

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The tooltip for downvotes says "This question does not show any research effort; it is unclear or not useful." Well, there you have it. – EJoshuaS - Stand with Ukraine Aug 03 '17 at 16:45
That's fair enough. – Felipe Aug 03 '17 at 16:48
Is there any specific reason why Partial methods does not supports OUT parameters ? – Tony Aug 03 '17 at 17:53

Partial Methods in C# and parameters

1 Answers1