CODEWITHSUNDEEP
c#.net
Miguel
Miguel

Reputation: 2079

Force function to return value and make compile error C#

I have a class and a method within that class. However this class method returns a string. When I call the class method I don't get an error even though I'm not catching the string value return. Is there a way that I can make C# and .net force me to capture the value when returning a value. Here is an example of what I mean.

1- create a class test.

class test
    {

        public string mystring() {

            return "BLAH";

        }
    }

2- call the class method from program or another class

test mystring = new test();
mystring.mystring();

My compiler while working in Visual Studio does not complain that I'm not capturing the return value. Is this normal or I'm missing something. Can I force the compiler to notify me that the function returns a value but I'm not catching it?

Thanks in advance for any suggestions you may have.

Upvotes: 8

Views: 2325

Answers (5)

AstroBeef
AstroBeef

Reputation: 1

For some future person who comes across this issue, you can use an 'out'. This will force you to always assign the variable.

public void mystring(out returnString) {

    returnString = "BLAH";

}

...

string OutString;
test mystring = new test();
mystring.mystring(out OutString);

Upvotes: 0

Evgeniy Mironov
Evgeniy Mironov

Reputation: 787

If your function has side effects then your should create unused variable and catch value. Compiler on release options delete this variable.

But if you don't have side effects in function: you may use visual studio tools such as "Watch window" and "Immediate window"

Upvotes: 0

MikeH
MikeH

Reputation: 4395

You could convert this to a property instead of a method:

  public string myString
  {
    get
    {
      return "Blah";
    }
  }

Then you can't compile if you simply call the property:

myString.myString; //Results in "Only assignment, call, increment, decrement, await, and new object expressions can be used as a statement" Error

Upvotes: 9

Steve Lillis
Steve Lillis

Reputation: 3256

You can try turning on warnings as errors by right-clicking the project in solution explorer, clicking Properties, going to the Build tab and setting Treat warnings as errors to all. This will force you to resolve all warnings before you can build and will capture some of the you-didn't-assign-this scenarios.

The compiler can't know that the only purpose of your method is to return the string or if it does some work that affects state, and so it can't complain when you don't assign the result to anything.

You can, however, set it up as a get only property per MikeH's answer. This will complain when you don't assign it to anything.

Upvotes: 1

Stewart_R
Stewart_R

Reputation: 14485

In a word, no. Not by force as such.

It's commonplace to not capture return values. Examples in the core libs abound (adding elements to a Hashset<T> for example, the function actually returns a bool to flag whether it was actually added or if it already existed - depending on individual implementation I may or may not care about that).

Of course, you can always just do something like string str = MyFunction() each time then never use str but I guess you probably already knew that.

Upvotes: 1

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